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Doosan G643E Service Manual

Lp engine for g35s-5, g40s-5, g45s-5, g50c-5, g55c-5, gc35s-5, gc40s-5, gc45s-5, gc50c-5, gc55c-5, g40sc-5, g45sc-5, g50sc-5, g55sc-5, g50s-5, g60s-5, g70s-5
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Service Manual
643
G
E LP Engine
643
G
LP Engine
G35S-5, G40S-5, G45S-5, G50C-5, G55C-5
GC35S-5, GC40S-5, GC45S-5, GC50C-5, GC55C-5
G40SC-5, G45SC-5, G50SC-5, G55SC-5
G50S-5, G60S-5, G70S-5
SB4263E01
Dec. 2008

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Summary of Contents for Doosan G643E

  • Page 1 SB4263E01 Dec. 2008 Service Manual E LP Engine LP Engine G35S-5, G40S-5, G45S-5, G50C-5, G55C-5 GC35S-5, GC40S-5, GC45S-5, GC50C-5, GC55C-5 G40SC-5, G45SC-5, G50SC-5, G55SC-5 G50S-5, G60S-5, G70S-5...

  • Page 3: Important Safety Information

    If a tool, procedure, work method or operating technique not specifically recommended by DOOSAN is used, you must satisfy yourself that it is safe for you and others. You should also ensure that the product will not be damaged or made unsafe by the operation, lubrication, maintenance or repair procedures you choose.
  • Page 5 Index Inspect for Intake Leaks........ 28 Chapter 1. GENERAL INFORMATION Inspect Throttle Assembly......28 Checking the TMAP Sensor(G643E only) ..28 Precautions before Service ......... 7 Tightening Torque ..........10 Exhaust System Maintenance......28 Recommended Lubricants and Capacities..12 Inspect Engine for Exhaust Leaks....28 Engine Model and Engine Serial Number ..
  • Page 6 Thermostat and Coolant Outlet ..... 90 General Description ........112 Torsional Damper ......... 90 Ignition System Control......113 Crankshaft Bearings........91 lgnition System Schematic for G643E ...114 Crankshaft Runout ........93 lgnition System Schematic for G643 ..114 Crankshaft End Play ........93 Ignition System Inspection ....115...
  • Page 7 EMS Inspection and Repair......181 Inspection of Spark Plug Wires .... 116 Engine Control Module[G643E]....181 Inspection of Spark Plug ...... 117 Crank Shaft Position Sensor [G643E] ..182 Inspection of EST Distributor....118 IAT (Intake Air Temperature) Sensor [G643E Inspection of Ignition Coil ..... 120 and G643] ...........184...
  • Page 8 Chapter 8. ADVANCED DIAGNOSTICS N2001 Regulator Disassembly Steps: .. 224 N2001 Disassembled Service ....226 Reading Diagnostic Fault Codes .....250 Displaying Fault Codes (DFC) from SECM Chapter 7. BASIC TROUBLESHOOTING Memory .............250 Clearing Fault (DFC) Codes ......250 Preliminary Checks.......... 227 Fault Action Descriptions ........251 Before Starting..........

  • Page 9: Precautions Before Service

    Chapter 1. GENERAL INFORMATION Precautions before Service Tightening Torque Removal and Disassembly Tighten the part properly to specified torque. Sealant For prevention of wrong installation or reassembly and for ease of operation, put mating marks to the parts where no function is adversely affected. Special Tool Use specified brand of sealant.
  • Page 10 Replacement Part Genuine Part When oil seal, O-ring, packing and gasket have When the part is to be replaced, be sure to use been removed, be sure to replace them with new genuine part. parts. For selection of appropriate parts, refer to the Parts However, rocker cover gasket may be reused if it is Catalog.
  • Page 11 Precautions for catalytic Converter CAUTION If a large amount of unburned gasoline flows into the converter, it may overheat and create a fire hazard. To prevent this, observe the following precautions and explain them to your customer. 1. Use only unleaded gasoline. 2.

  • Page 12: Tightening Torque

    Tightening Torque Tightening Torque Table of Standard Parts Torque (kg·m) Bolt nominal diameter Pitch (mm) (mm) Head mark 4 Head mark 7 0.3 ~ 0.4 0.5 ~ 0.6 0.5 ~ 0.6 0.9 ~ 1.1 1.25 1.2 ~ 1.5 2.0 ~ 2.5 1.25 2.5 ~ 3.0 4.0 ~ 5.0...
  • Page 13 General tightening torque for bolts, nuts and taperlock studs The following charts give the standard toque thread Standard torque values for bolts, nuts and taperlock studs of size SAE Grade 5 or better quality. Exceptions are given in other sections of the Service Manual where needed.

  • Page 14: Recommended Lubricants And Capacities

    Recommended Lubricants and Capacities Recommended Lubricants Lubricant Specification Remarks Engine Oil API Classification SJ or above SAE 10W30 or SAE 5W30 Automotive antifreeze Concentration level 50%(normal) Coolant (Antifreeze) suitable for gasoline engines Concentration level 40%(tropical) having aluminum alloy parts Lubricant Capacities Description G(C)35/40/45S-5,G50/60/70S-5 Oil Pan...

  • Page 15: Engine Model And Engine Serial Number

    • Comply with EPA 2007 Emission Regulation G643E/G643 30700001 to 39999999 • Electronic Control by ECM Features and Benefits of G643E/G643 Engine • Certified LP System available • Valve seat inserts – Closed loop LP Carburetion system – Valve seat system •...

  • Page 16: General Specification

    General Specification G643E Engine G643 Engine GENERAL DESCRIPTION ENGINE TYPE: 90°4-Cycle V6, Water Cooled COMBUSTION SYSTEM: Naturally Aspirated INTAKE MANIFOLD Cast Iron, Dry EXHAUST MANIFOLD Cast Iron, Dry Pushrod Actuated Overhead Valves - 2 Per Cylinder VALVE CONFIGURATION: Auto Lash adjustment by hydraulic valve lifter...
  • Page 17 G643E Engine G643 Engine LP FUEL SYSTEM Closed loop LP Carburetion Open loop LP Carburetion LP FUEL SYSTEM System System Diaphragm Type Air Valve Diaphragm Type Air Valve MIXER: Assembly inside, Downdraft Assembly inside, Downdraft (Model: CA-100) (Model: CA-100) Two-Stage Negative Pressure...
  • Page 18 G643/G643E Engine Power and Torque ENGINE MODEL unit G643E-LP G643-LP RATED POWER 69.4 69.4 93.0 93.0 94.3 94.3 2,450 2,450 MAX TORQUE lbf-ft kgf-m 29.0 30.0 1600 1600 GOVERNED SPEED 2500 2500 LOW IDLE G643(E) Service Manual Chapter 1. General Information...

  • Page 19: Chapter 2. Recommended Maintenance

    Chapter 2. RECOMMENDED MAINTENANCE Suggested maintenance requirements for an engine equipped with an MI-07 fuel system are contained in this section. The operator should, however, develop a customized maintenance schedule using the requirements listed in this section and any other requirements listed by the engine manufacturer. General Maintenance Inspect Engine for Fluid Leaks •...

  • Page 20: Engine Oil Classification

    Engine Oil Classification Recommended API classification: Above SJ Recommended SAE viscosity classification *1. 10W-30 engine oil is recommended If 10W-30 is not applicable, proper engine oil will be possible according to temperature ranges. The following lubricants should be selected for all engines to enhance excellent performance and maximum effect.

  • Page 21: Checking Engine Oil Level

    Checking Engine Oil Level Replacing Engine Oil and Filter CAUTION Prolonged and repeated contact with mineral oil will result in the removal of natural fats from the skin, leading to dryness, irritation and dermatitis. In addition, used engine oil contains potentially harmful contaminants which may cause skin cancer.

  • Page 22: Checking Compressed Pressure

    3. Refill with engine oil filter. CAUTION 1) Clean and install the oil drain plug with a new At this time, necessarily screen the spark plug gasket. hole with a rag. Because hot coolant, oil, fuel, and other foreign material, being penetrated in Torque 40~70 N•m the cylinder through cracks can come into the...

  • Page 23: Cooling System Maintenance

    DOOSAN prefers the use of distilled water or deionized water to reduce the potential and severity of chemical insolubility.

  • Page 24: Checking Coolant Leaks

    Checking coolant leaks 1. After the coolant temperature drops below 38°C loosen the radiator cap. 2. Check that the coolant level reaches filler neck. 3. Install the radiator cap tester to the radiator filler neck and apply a pressure of 1.4kg/cm2 . While maintaining it for 2 minutes, check the radiator, hose, and connecting part for leak.

  • Page 25: Checking And Adjusting Drive Belt

    Checking and Adjusting Drive Belt Checking Belt for Damage Check the following items and replace the belt if defective. 1. Check the belt surface for damage, wear and crack. 2. Check the belt surface for oil or grease contamination. 1. Checking tension 3.

  • Page 26: Ignition System Maintenance

    Because ignition timing is fixed by set data baking soda and water. value in ECU, it is impossible to control on purpose. (G643E Engine) • Inspect battery outer surfaces for damage and Fist, check that sensors send output properly to replace as necessary.

  • Page 27: Inspection Of Spark Plug

    Inspection of Spark Plug Inspection and clean 3. Check the spark plug as below. 1) Insulator broken 1) Ignition cable 2) Terminal worn 3) Carbon deposit 1. Disconnect the ignition cables from spark plugs. 4) Gasket damaged or broken 2. Remove all spark plugs from the cylinder head using a sparkplug wrench.
  • Page 28 park Plugs 5. Install the spark plug and tighten it to the specified torque. Take care not to over tighten it to prevent cylinder head threads from damage. Tightening torque 25~30 N•m SPARK PLUG ANALYSIS State Contact point is Contact point is black white Description...

  • Page 29: Fuel System Maintenance

    Fuel System Maintenance 8. Re-assemble the filter assembly aligning the scribe lines on the top and bottom covers. Replace LP Fuel Filter Element 9. Install the cover retaining screws, tightening the screws in an opposite sequence across the cover. Park the lift truck in an authorized refueling area with the forks lowered, parking brake applied and the 10.

  • Page 30: Pressure Regulator/Converter Inspection

    Pressure Regulator/Converter Checking the TMAP Sensor(G643E only) Inspection • Verify that the TMAP sensor (F) is mounted tightly into the manifold or manifold adapter (E), with no • Visually inspect the pressure regulator/converter leakage. (B) housing for coolant leaks. • If the TMAP is found to be loose, remove the •...

  • Page 31: Maintenance Schedule

    Maintenance Schedule NOTE: The MI-07 fuel system was designed for use with LPG fuel that complies with HD5 or HD10 LPG fuel standards. Use of non-compliant LPG fuel may require more frequent service intervals and will disqualify the user from warranty claims. INTERVAL HOURS Every Every...
  • Page 32 INTERVAL HOURS Every Every Every Every Every Every CHCK POINT 1000 1500 2500 3000 Daily Hours Hours Hours Hours Hours Hours 1 month 3 month 6 month 9 month 15 month 18 month Pressure Regulator/Converter Test regulator pressures. Inspect pressure regulator vapor hose for deposit build-up.

  • Page 33: Chapter 3. Engine Mechanical System

    Chapter 3. ENGINE MECHANICAL SYSTEM General Information Engine Outline G643 (E) Service Manual Chapter 3. Engine Mechanical System...
  • Page 34 Specification Crankshaft Crankshaft Journal General Diameter #1 Type ..........90 Degree V6 ....62.199-62.217 mm (2.4488-2.4495 in) Displacement ......... 4.3L (262 CID) Diameter 2, #3 RPO (VIN Code) ......L35 (W), LF6 (X) ....62.192-62.215 mm (2.4485-2.4494 in) Bore.........101.6 mm (4.00 in) Diameter #4 Stroke........

  • Page 35: Torque Specification

    ..High Limit Production + 0.0257 mm (.001 in) Intake Manifold Bolts Exhaust First Pass ........3 N·m (27 lb·ft) ..High Limit Production + 0.0508 mm (2.03 in) Second Pass ......12 N·m (106 lb·ft) Valve Spring Free Length....52 mm (2.03 in) Final Pass .......
  • Page 36 Oil Pan Oil Filter Tightning Specifications for Oil Pan Tightening Specifications for Oil Filter (1) ............Oil Pan (1) Wipe clean the filter adapter in the area that the new filter makes contact. Put clean engine oil on (2) Torque for Plug....... 45 N· m (33 lb· ft) the new filter gasket.
  • Page 37 Exhaust Manifolds Intake Manifolds Exhaust Manifold Left Side Tightening Specifications for Intake Manifolds Intake manifold bolt in three steps using sequence shown in IAGS023S First pass ........3 N·m (27 lb·ft) Second pass ......12 N·m (106 lb·ft) Third pass ........15 N·m (11 lb·ft) Exhaust Manifold Right Side Tightening Specifications for Exhaust Manifold.
  • Page 38 Flywheel Housing Flywheel (1) Flywheel housing bolts should be torqued to (1) Torque for the bolts that hold the flyweel to the ........40 to 45 N·m (30 to 35 lb·ft) crankshaft100 N·m (74 lb·ft) (2) Use a torch. Heat the ring around the entire Flywheel Face Runout circumference, then drive the gear off the flywheel using care not to damage the flywheel...
  • Page 39 Flywheel Runout Pressure Cap For checking procedure, see Flywheel And Flywheel Housing in the Testing And Adjusting section. Face Runout (Axial Eccentricity). For testing procedure, see Cooling System Tests in the Testing And Adjusting section. Pressure valve opening pressure ........85 to 110 kPa (12 to 16 psi) Maximum permissible face runout of the flywheel Vacuum valve opening pressure ..........0.19 mm (.0075 in)
  • Page 40 Camshaft Balance Shaft (1) Torque for camshaft sprocket bolts (1) Front Bearing Journal Diameter ..........20 N· m (15 lb· ft) ..55.985 to 55.001 mm (2.1648 to 2.1654 in) (2) Torque for retainer mounting bolts (2) Rear Bearing Journal Diameter ..........
  • Page 41 Front Gear Cover Height of camshaft lobes (A) Intake lobe ....... 7.018 mm (.2763 in) (B) Exhaust lobe ....7.252 mm (.2855 in) (1) The front gear cover (1) of the engine must be (C) Maximum permissible difference actual & replaced if it is removed for any reason.
  • Page 42 Cylinder Heads Valve Clearence Tools Needed Torque Angle Meter (1) The 4.3 liter engine has screw-in rocker arm studs with positive stop shoulders, NO valve adjustment is necessary. When the valve train requires service you simply tighten the rocker arm nuts to 25 N·m (18 lb·ft). NOTE : When installing the cylinder heads use a new head gasket.

  • Page 43: Engine Exploded View

    Engine Exploded View G643 (E) Service Manual Chapter 3. Engine Mechanical System...
  • Page 44 UPPER ENGINE PARTS ITEM # DESCRIPTION ITEM # DESCRIPTION COVER, VALVE ROCKER ARM (RH) MODULE, DIST. IGN. CONT. (PT OF 3) COVER, VALVE ROCKER ARM (LH) SHAFT, DISTRIBUTOR (PT OF 3) CAP, OIL FILL RETAINER, DIST. IGN P/U COIL DISTRIBUTOR BOLT, IGNITION COIL BOLT, DISTRIBUTOR CLAMP COIL, IGN.
  • Page 45 G643 (E) Service Manual Chapter 3. Engine Mechanical System...
  • Page 46 LOWER ENGINE PARTS ITEM # DESCRIPTION ITEM # DESCRIPTION RING KIT, PISTON (STD) FITTING, O IL FILTER KIT, PISTON (0.50 MM O.S.) FILTER, O IL PISTON KIT, ENGINE (STD) GEAR, FLYWHEEL RING PISTON KIT, ENGINE (0.50 MM O.S.) BALANCER, CRANKSHAFT ROD, CONN (INCL.

  • Page 47: Engine Construction

    Engine Construction the bearing uses a sleeve-type bearing. The 4.3L (262 CID) engine is a liquid-cooled 90 V6 Valve Train type with overhead valves, cast-iron block, cylinder heads, and cast-iron balance shaft. The valve train is a ball pivot type. Motion is transmitted from the camshaft through the valve Cylinder Block lifter and valve pushrod to the rocker arm.

  • Page 48: Use Of Rtv Sealer And Anaerobic Gasket Eliminator

    Use Of Rtv Sealer And Anaerobic Gasket Using Anaerobic Gasket Eliminator Eliminator 1. Clean surfaces to be resealed with a chlorinated Two types of sealer are commonly used in the solvent (GM P/N 1050454 or equivalent) to engines covered by this manual. These are RTV remove all oil, grease, and old material.

  • Page 49: Replacing Engine Gaskets

    Replacing Engine Gaskets 1. Determine size, pitch, and depth of damaged thread. If necessary, adjust stop collars on cutting tool and tap to required depth. CAUTION IMPORTANT: Refer to the kit manufacturer's Composite type gaskets are used in some areas instructions regarding the size of drill and tap to of the engine assembly.

  • Page 50: Special Tools

    Special Tools Tool # Description J 21882 Oil Pickup Tube and Screen Installer J 23738-A Valve Seal Leak Detector J 24086-B Piston Pin Remover and Installer Set J 24270 Ridge Reamer J 3049-A Valve Lifter Remover J 33049 Camshaft Bearing Remover and Installer J 34673 Straightedge J 35621...
  • Page 51 J 5590 J 3049-A Crankshaft Sprocket Valve Lifter Remover Installer J 6098-01 J 5715 or J 6036 Camshaft Bearing Rocker Stud Hole Reamer Remover/Installer J 5239 J 8062 Connecting Rod Bolt Guide Valve Spring Compressor J 8087 J 8089 Cylinder Bore Gauge Carbon Remover Brush J 7872 J 8001...
  • Page 52 J 9290-01 J 8 037 Valve Lifter Remover Piston Ring Compressor (Slide Hammer Type) J 24086-C J 24270 Piston Pin Remover/ Ridge Reamer Installer Set J 24420-C Universal J 21882 Crankshaft Pulley Oil Suction Pipe Installer Remover J 35621 Crankshaft Rear Oil Seal Installer G643 (E) Service Manual Chapter 3.

  • Page 53: Cooling System

    Cooling System General Description Cooling System Schematic (1) Cylinder head. (2) Thermostat. (3) Recovery tank. (5) Radiator top hose. (6) Radiator pressure cap. (7) Cylinder walls. (8) Radiator. (9) Radiator lower hose. (10) Water pump. Water pump (10) is installed on the front of the thermostat (2) is open the coolant will go through cylinder block.

  • Page 54: Testing & Adjusting

    Testing & Adjusting 5. Inspect the drive belts for the fan. Adhere to the following warnings when performing 6. Check for damage to the fan blades. any tests or adjustments while the engine is running: 7. Look for air or combustion gas in the cooling system.
  • Page 55 Pressure Cap Test Cooling System Leak Check To test the cooling system for leaks, use the following procedure: WARNING If the engine has been in operation and the coolant is hot, slowly loosen the pressure cap to the first stop and let the pressure out of the cooling system, then remove the pressure cap.

  • Page 56: Operation

    Thermostat Cooling System Heat Problems The thermostat is the wax pellet type. A jiggle valve To check if there is a good reason for heat problems (which improves air bleeding during water supply) is do the checks that follow: provided on the flange part. When the thermostat is closed, the circulation of coolant is stopped, thereby 1.

  • Page 57: Cooling System Recommendation

    In addition, if the concentration is above 60%, both the antifreeze and engine DOOSAN prefers the use of distilled water or cooling properties will decrease, adversely deionized water to reduce the potential and severity affecting the engine.
  • Page 58 Make proper antifreeze additions. Adding pure antifreeze as a makeup solution for cooling system top-up is an unacceptable practice. It increases the concentration of antifreeze in the cooling system which increases the concentration of dissolved solids and undissolved chemical inhibitors in the cooling system.

  • Page 59: Engine Lubrication

    Engine Lubrication Filtered oil flows into the main gallery and then to the camshaft, balance shaft, rear bearing, and crankshaft bearings. The valve lifter oil gallery General Description supplies oil to the valve lifters. Oil flows from the valve lifters through the hollow valve pushrods to the Full pressure lubrication, through a full-flow oil filter rocker arms.
  • Page 60 Testing and Adjusting Adhere to the following warnings when performing any tests or adjustments while the engine is running. WARNING Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury. WARNING Engine Oil Viscosity Recommendation Exhaust fumes contain carbon monoxide (CO)
  • Page 61 Too Much Oil Consumption Before starting the engine, the engine oil light(1) on the instrument panel will turn on when the key • Engine outside oil leakage switch is turned to the ON position. The light will turn off after the engine is started and while the engine is Check for leakage at the seals at each end of the running, lidicating normal oil pressure.

  • Page 62: Disassembly Of Engine

    Disassembly of Engine It is beyond the scope of this Section to cover in detail the many different accessory installations. Refer to the appropriate service manual section for English and Metric Fasteners this information. Diagrams of emissions and vacuum hose routings, CAUTION wiring harness routing, accessory drive belt layout, Late model engines use a combination of...

  • Page 63: Exhaust Manifold Removal

    Exhaust Manifold Removal Tighten • Coolant drain plug and/or knock sensor to Figure 12-4 14 N·m (124 lb. in.). • Drain plug to 25 N·m (18 lb·ft.). Engine Flywheel Removal Figure 12-3 Remove or Disconnect 1. Engine flywheel bolts. 2. Engine flywheel. Figure 12-4 Exhaust Manifold Remove or Disconnect 1.
  • Page 64 High Mounted Fan Bracket Removal Start By: a. Remove fan belt. b. Remove wires from alternator. 1. Remove bolts from pump pulley. 1. Remove (5) Bolts from bracket. 2. Remove the bracket assembly. 2. Remove pulley from pump. Note: For installation of the fan bracket, reverse the removal steps and torque mounting bolts to 50 N·m (37 lb·ft.).

  • Page 65: Valve Rocker Arm Cover Removal

    < Components > 4. Remove pump from engine. 5. Remove gasket and clean surface. 1. Gasket-Thermostat Housing 2. Thermostat Housing Spacer Valve Rocker Arm Cover Removal 3. Thermostat Assembly 4. Housing-Thermostat 5. Bolt 6. ECT Sensor-SECM 7. Plug 8. Fitting Figure 12-5 9.

  • Page 66: Intake Manifold Removal

    Intake Manifold Removal Remove or Disconnect Start By: IMPORTANT: Store all reusable components in an exact order so they can be reassembled in a. Remove fuel lines and linkage from carburetor. the same wear pattern location from which they were removed. Mark the front end of the retainer. b.

  • Page 67: Cylinder Head Removal

    1. Remove spark plugs from cylinder head assemblies. Figure 12-7 Removing Valve Lifter 2. Remove bolts from cylinder head. Figure 12-8 Removing Valve Lifter Cylinder Head Removal Remove or Disconnect 3. Remove cylinder heads from block. Start By: a. Removing high mounted fan bracket. b.

  • Page 68: Oil Pan Removal

    Oil Pan Removal Figures 12-10 and 12-11 Remove or Disconnect 1. Oil filter adapter bolts. 2. Oil filter adapter gasket. 3. Oil filter adapter O-ring seal, if equipped. 4. Oil filter adapter. 5. Oil pan nuts. 6. Oil pan bolts. 4.

  • Page 69: Oil Pump Removal

    Oil Pump Removal Figure 12-12 Remove or Disconnect 1. Bolt from oil pump to main bearing cap. 2. Oil pump assembly. 3. Driveshaft and retainer. 1. Remove bolts from cover. 2. Remove cover from engine. Figure 12-12 Oil Pump Timing Chain and Camshaft Sprocket Engine Front Cover Removal Removal IMPORTANT: Once the composite cover is...

  • Page 70: Camshaft Removal

    B. Pull the camshaft out from the block being careful to prevent damage to the camshaft bearings. Figure 12-13 Timing Chain and Sprockets Remove or Disconnect 1. Camshaft sprocket bolts. 2. Camshaft sprocket and camshaft timing chain together. Figure 12-14 Removing Camshaft IMPORTANT: The sprocket has a light inter- ference fit on the camshaft.

  • Page 71: Piston And Connecting Rod Removal

    IMPORTANT: The balance shaft with front bearing are serviced as an assembly. Use only the correct tools for bearing and shaft installation. Inspect the balance shaft driven gear and the drive gear for nicks and burrs. Piston and Connecting Rod Removal Figures 12-18 and 12-19 Tools Required: J 24270 Ridge Reamer...

  • Page 72: Crankshaft Rear Oil Seal Removal

    Crankshaft Rear Oil Seal Removal IMPORTANT: Marking them from the front to the rear, with the engine in an upright position and viewed from the front: Figure 12-20 • The right bank is numbered 1-3-5. Remove or Disconnect • The left bank is numbered 2-4-6. NOTICE: Take care when removing the rear crank- shaft oil seal so as not to damage the crankshaft 3.

  • Page 73: Crankshaft Removal

    Crankshaft Removal Inspect • Check the main bearing caps for location markings. Mark the caps if necessary. The caps must be returned to their original locations during assembly. Remove or Disconnect Notice Be sure to mark bearings, rod and piston 3.

  • Page 74: Cleaning, Inspection, And Repair

    Cleaning, Inspection, and Repair Cylinder Block A solvent tank large enough to hold the larger engine parts will be needed as well as various bristle Figures 12-22 through 12-25 brushes gasket scrapers. source compressed air will also be helpful in the cleaning Remove or Disconnect operations.

  • Page 75: Cylinder Bore

    Figure 12-24 Rear Cylinder Block Oil Gallery Plugs Figure 12-25 Measuring Cylinder Block Surface Flatness Clean - If the gap is greater than 0.05 mm (0.002 in.) within 152 mm (6 in.) at any sealing location, • Sealing material from mating surfaces. the block must be replaced.
  • Page 76 1. Refer to “Specifications” for tolerances. 2. Set the gage so the thrust pin must be forced in about 7 mm (0.250 in.) to enter the gage in the cylinder bore. 3. Center the gage in the cylinder and turn the dial to “0”.
  • Page 77 Boring 2. Occasionally, during the honing operation, the cylinder bore should be thoroughly cleaned and 1. Before the honing or reboring operation is the piston selected for the individual cylinder started, measure all new pistons with the checked for correct fit. micrometer contacting at points exactly 90°...

  • Page 78: Piston Disassembly

    11. Apply clean engine oil to each bore to prevent Remove or Disconnect rusting. 1. Piston rings. In most cases, the rings should be NOTICE: Refer to “Notice” on page 1. discarded and replaced with new ones at assembly. Install or Connect 2.
  • Page 79 Measure 1. Piston pin diameter. Check against “Specifications.” 2. Piston pin-to-piston clearance. A. Measure the piston pin hole diameter. B. Subtract the piston pin diameter from the piston pin hole diameter to obtain the clearance. Figure 12-30 Removing Piston Rings C.

  • Page 80: Piston Selection

    Piston Selection Piston Assembly Figures 12-34 and 12-35 Assembling the Piston and Connecting Rod 1. Check the used piston to cylinder bore clearance. Figure 12-36 Measure Tool Required: A. Cylinder bore diameter. Use a telescoping J 24086-B Piston Pin Remover and Installer Set bore gage, located 65 mm (2.5 in.) below the top of the cylinder bore (figure 12-34).
  • Page 81 C. Adjust the piston pin installer (J 24086-9) to Inspect the correct length, using the letter-number scale on the installer adjuster. This is 1. Ring fit as follows: necessary to ensure that the piston pin is pressed into the piston to the correct depth. A.

  • Page 82: Intake And Exhaust Manifolds

    Camshaft Measure • Ring clearance. Use a feeler gage and compare Figures 12-41 and 12-42 with “Specifications”. Tool Required: J 7872 Dial Indicator or Equivalent IMPORTANT: Do not attempt to repair the camshaft, replace it if damaged. Whenever the camshaft is replaced, a new set of lifters must also be installed.

  • Page 83: Camshaft Bearings

    Camshaft Bearings Cleaning and Inspection Camshaft Bearing Removal Clean Figure 12-43 • Camshaft bearing bores in the block. Tool Required: Inspect • J 33049 Camshaft Bearing Remover and • Camshaft bearings for scratches, pits, or loose fit Installer in their bores. Replace the camshaft bearings if necessary.

  • Page 84: Balance Shaft

    Crankshaft Sprocket Replacement A. Coat a new camshaft plug with sealer GM P/N 12345493 or equivalent. Figure 12-44 B. Install the plug. The plug must be installed deep enough in camshaft bore. Tools Required: J 5825-A Crankshaft Sprocket Puller J 5590 Crankshaft Sprocket Installer Balance Shaft Remove of Disconnect Inspect...

  • Page 85: Coolant Pump

    Coolant Pump Oil Pump Clean Figures 12-46 and 12-47 • Old gasket from the gasket surface. Remove or Disconnect NOTICE: Do not immerse the pump in solvent. The 1. Driveshaft and retainer. solvent enter pump's permanently lubricated bearings and cause premature bearing IMPORTANT: Do not remove pickup pipe and failure.
  • Page 86 2. Pressure regulator spring into the pump cover. 3. Retaining pin into the pump cover. 4. Drive gear and shaft into the pump body. 5. Idler gear into the pump body. IMPORTANT: Match together the index marks on the two gears made during disassembly. 6.

  • Page 87: Valve Train Components

    Figure 12-47 Installing Oil Pump Screen Valve Train Components Inspect • With the shaft extension installed on the pump, IMPORTANT: Store all reusable components in turn the drive shaft by hand to check for smooth an exact order, so they may be reassembled in operation.

  • Page 88: Valve Lifters

    Valve Lifters This engine uses hydraulic valve lifters. Valve lifters are serviced only as an assembly. No internal parts are available. Service is limited to disassembly and cleaning. Discard valve lifters that are excessively worn or damaged. IMPORTANT: Whenever the camshaft needs to be replaced, a new set of hydraulic lifters must also be installed.
  • Page 89 D. Move the stem of the valve from side to side using light pressure to obtain a clearance reading. If clearance exceeds specifications, ream the valve guide bores for oversize valves as outlined later. 2. Valve spring tension. Use J 8056 or equivalent. •...
  • Page 90 Figure 12-53 Measuring Valve Spring Tension Figure 12-55 Valve / Seat Grinding Figure 12-54 Measuring Valve Spring Length Repair Figure 12-56 Critical Valve Dimensions Figures 12-55 through 12-58 Valve Grinding Pitted valves must be refaced to the proper angle. Valve stems that show excessive wear, or valves that are warped excessively must be replaced.
  • Page 91 Valve Seat Grinding Reconditioning the valve seats is very important. The seating of the valves must be perfect for the engine to deliver the power and performance it was designed to produce. Another important factor is the cooling of the valve head.

  • Page 92: Torsional Damper

    Thermostat and Coolant Outlet Measure 1. Valve spring installed height of each spring as Remove or Disconnect follows: 1. Bolts. A. Use a narrow thin scale. A cutaway scale may be helpful. 2. Stud. B. Spring seat in the cylinder head to the top of 3.

  • Page 93: Crankshaft Bearings

    Crankshaft Bearings Micrometer Method Figures 12-61 through 12-63 Measure Cleaning and Inspection 1. The crankshaft journal diameter with a micrometer in several places, approximately 90° Clean apart. Average the measurements. • Crankshaft with solvent. 2. Compute taper and runout. Refer to “Specifi- - Do not scratch the bearing journals.
  • Page 94 Plastigage Method Install or Connect 1. Main bearing inserts and crankshaft. 2. Gauging plastic. A. Begin with the rear main bearing. B. Wipe the oil from the crankshaft journal and the lower main bearing insert. C. Place a piece of gauging plastic the full width of the lower bearing insert (parallel to the crankshaft) on the journal (figure 12-62).

  • Page 95: Crankshaft Runout

    Crankshaft Runout b. Tighten bolts to specification. Figure 12-64 c. Firmly thrust end of the crankshaft first rearward then forward. This will line up the Measure rear main bearing and crankshaft thrust surfaces. Tool Required: d. With the crankshaft wedged forward, measure J 7872 Magnetic Base Dial Indicator at the front end of the rear main bearing with a feeler gage (figure 12-65).

  • Page 96: Connecting Rod Side Clearance

    Connecting Rod Side Clearance Figure 12-66 Measure • Connecting rod side clearance as shown in figure 12-66. Refer to “Specifications”. Figure 12-66 Measuring Connecting Rod Side Play G643 (E) Service Manual Chapter 3. Engine Mechanical System...

  • Page 97: Prior To Assembly

    Assembly of Engine NOTICE English and Metric Fasteners If any undersized bearing are used, they must be fitted to the proper journals. CAUTION Late model engines use a combination of English and Metric threaded fasteners. The components effected are starter motor, engine mounts, and flywheel housing mounting.

  • Page 98: Crankshaft Rear Oil Seal Installation

    Crankshaft Rear Oil Seal Installation Figure 12-68 Tool Required: J 35621 Seal Installer Install or Connect 1. Crankshaft rear oil seal. A. Lubricate the inner and outer diameter of the seal with engine oil. 7. Install rear crankshaft bearing and bolts Torque B.
  • Page 99 IMPORTANT: Connecting rod bearings are of the C. Without disturbing the ring end gap location, precision insert type and do not use shims for install J 8037 over the piston. adjustment. DO NOT FILE RODS OR ROD CAPS. D. The piston must be installed so that the notch If clearances are excessive, install a new bearing.

  • Page 100: Balance Shaft Installation

    IMPORTANT: Each connecting rod and bearing Tighten cap should be marked, beginning at the front of the engine. Cylinders 1, 3, and 5 are the right • Balance shaft retainer bolts to 14 N•m (124 lb.in.). bank and 2, 4, and 6 are the left bank (when viewed from the front of the engine).

  • Page 101: Camshaft Installation

    Tighten • Balance shaft driven gear bolt to 20 N∙m (15 lb. ft.) plus an additional turn of 35° using J 36660. IMPORTANT: Rotate balance shaft by hand to make sure there is clearance between the balance shaft and retainer. If balance shaft does not rotate freely, check to be sure retaining ring on front bearing is seated on case.

  • Page 102: Engine Front Cover Installation

    Engine Front Cover Installation IMPORTANT: Once the composite front engine cover is removed, DO NOT reinstall it. Always install a new engine front cover. Install or Connect 1. Engine front cover to engine. 2. Front cover bolts. NOTICE: Refer to “Notice” on page 1. Figure 12-77 Installing Camshaft Tighten Timing Chain and Camshaft Sprocket...

  • Page 103: Torsional Damper Installation

    Torsional Damper Installation Oil Pump Installation Figure 12-79 Figure 12-80 Tool Required: Install or Connect J 39046 Torsional Damper Puller and Installer 1. Oil pump to the engine. Install or Connect • Align the slot in the oil pump shaft with the tang on the distributor shaft.

  • Page 104: Oil Pan Installation

    Oil Pan Installation Figures 12-81 through 12-85 Tool Required: J 34673 Straightedge or equivalent Install or Connect 1. Apply RTV sealant (GM P/N 12346141) or equivalent to the front cover to block joint and to the crankshaft rear retainer seal to block joint. Apply the sealant about 25 mm (1.00 in.) in both directions from each of the four corners (figures 12-81 and 12-82).
  • Page 105 Figure 12-84 Oil Pan Tightening Sequence Figure 12-85 Oil Filter Adapter Installation With Oil Cooler (Typical) G643 (E) Service Manual Chapter 3. Engine Mechanical System...

  • Page 106: Cylinder Head Installation

    Cylinder Head Installation Figure 12-86 Tool Reqired: J 36660 Torque Angle Meter Clean • Gasket surfaces on the block and cylinder head Install or Connect Figure 12-86 Cylinder Head Bolt Tightening Sequence 1. Head Gasket IMPORTANT: Do not use sealer on head gaskets. Place the gasket over the block dowel pins with the head up.

  • Page 107: Rocker Arm Cover Installation

    Install or Connect 4. Intake manifold bolts. 1. Valve lifters to the block. Tighten 2. Valve lifter guide and bolts. Note previously made mark on the valve lifter guide. Reference • Intake manifold bolts in three steps using mark should be pointing toward front of engine. sequence shown in figure 12-90.
  • Page 108 Figure 12-89 Intake Manifold Sealer Application Figure 12-90 Intake Manifold Tightening Sequence Figure 12-91 Valve Rocker Arm Cover Installation G643 (E) Service Manual Chapter 3. Engine Mechanical System...

  • Page 109: Exhaust Manifold Installation

    Exhaust Manifold Installation Figures 12-92 Install or Connect 1. Exhaust manifold gaskets. 2. Exhaust manifold. 3. Heat shield. 4. Exhaust manifold bolts and / or nuts. Tighten • Bolts in two steps, beginning with the two center bolts: A. Bolts to 15 N·m (11 lb· ft.). B.

  • Page 110: Engine Flywheel Installation

    Engine Flywheel Installation Figure 12-93 Install or Connect 1. Flywheel. 2. Flywheel bolts. Tighten • Bolts to 100 N•m (74 lb· ft.). 3. Check flywheel runout using a dial indicator. If runout is excessive, remove flywheel, check and clean mounting surfaces and install flywheel. Check runout again.

  • Page 111: Engine Accessory Installation

    Coolant Pump Installation 4. Crank the engine several times. Listen for anyunusual noises or evidence that parts are Install or Connect binding. 1. Install gasket to block 5. Refer to “Specifications” for ignition timing adjustment. 2. Install pump to location. 6.

  • Page 112: Specifications

    Chapter 4. ENGINE ELECTRICAL SYSTEM Specifications Ignition Coil Ignition Timing Rating............12 Volts Resistance between B+ and ground (coil mounting The correct timing is when the flywheel housing bracket) ............in finite pointer is in alignment with the correct mark on the flywheel or when the single digit mark on the Resistance between B+ and C-....
  • Page 113 Distributor Sensor Gap The Air gap (X) between the trigger wheel and the module is preset by General Motors. Therefore no adjustment can be made or is required. (1) Shaft end play ...197 to 198 mm (7.75 to 7.80 in) The distributor end play will be checked with the distributor in an inverted position from normal.

  • Page 114: Ignition System

    Ignition System General Description Ignition System Schematic (1) Battery. (2) Ignition switch. (3) Coil. (4) Distributor. (5) Spark plug. The ignition system has battery (1), ignition switch (2), coil (3), distributor (4) with inner electronics circuits and spark plugs (5). The battery and ignition switch have terminals and closed contacts to permit battery current flow through the ignition system.
  • Page 115 Ignition System Control rotor arm and spark plug wires. The SECM uses the signal from the GM (General Motors) Delco Ignition Spark-ignited engines require accurate control of Module to determine the engine position and RPM spark timing and spark energy for efficient at any time.
  • Page 116 System Schematic for G643E SECM48 CRANK lgnition System Schematic for G643 IGNITION COIL DISTRIBUTOR ECUP_AN1 EST1 (5V) CNK + SECM24 CONNECTION CLOSE TO THE MODULE SPARK PLUGS G643(E) Service Manual Chapter 4. Engine Electrical System...

  • Page 117: Ignition System Inspection

    Ignition System Inspection Adhere to the following warnings when performing any tests or adjustments while the engine is running. WARNING Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury. WARNING Inspection of Distributor Rotor (2) Distributor rotor.
  • Page 118 Resistance Testing 1. Disconnect both ends of ignition cable (rotate boot and pull at the boot only) being tested and clean terminals. 2. Set ohmmeter on high scale and connect ohmmeter to each end of cable being tested. Twist cable gently while observing ohmmeter. 3.
  • Page 119 Inspection of Spark Plug Inspection and clean 1. Disconnect the ignition wires from the ignition coil ass’y. 2. Remove all spark plugs from the cylinder head using a spark plug wrench. CAUTION Take care not to come foreign materials into 4.
  • Page 120 Delco Distributor Module Testing Inspection of EST Distributor Description NOTICE An approved module tester must be used in order to The Delco EST ignition system consists of the check the module. Use a Kent-Moore Module Tester distributor, ignition coil, wiring and spark plugs. The or equivalent.
  • Page 121 Pickup Coil Testing Test 1 Tester Connections 1. Remove The distributor cap and rotor. 2. Disconnect the pickup coil leads from the module. 3. Connect an ohmmeter between the pickup coil lead and housing (test 1, IAGS059S). Reding should be infinite (no continuity). 4.

  • Page 122: Disassembly And Assembly

    Disassembly and Assembly Inspection of Ignition Coil Ignition Coil Remove & Install Coil 1. Connect ohmmeter between "B+" or "C-" 1. Disconnect wire connectors (1) from the coil. terminals and ground (coil-mounting bracket). On high scale, reading should be infinite (test 1, IAGS004S).
  • Page 123 Install Distributor EST Distributor Remove Distributor 1. Install the distributor (1) in position in the intake manifold. Make sure that the rotor (2) is in alignment with the scribe mark and number one 1. Disconnect coil harness (1) from distributor. cylinder.
  • Page 124 Disassemble Distributor Start By: Removing the distributor. 6. Pry off spring washer and remove retainer (8). 1. Remove rotor (1) 7. Unplug and remove the pickup coil (9). 8. Remove two screws (10) and remove pickup module (11). 2. Remove gasket (2) from location. 3.
  • Page 125 Ignition Timing Adjustment for G643 Engine DISTRIBUTOR The ignition timing advance of G643 is controlled by the SECM. The initial ignition timing setting of the distributor is described in the following steps. It will IGNITION be necessary to mechanically adjust the distributor MODULE to an initial setting for startup, and then adjust the final timing using the Service Tool.
  • Page 126 Figure 42. Spark Control Lock Parameter Figure 38. Topside of Engine Showing Position “Unlocked” of Cylinders 2. The preferred reference timing to use for NOTE: This completes the initial ignition timing. The verification with a timing light is 10 degrees BTDC. final ignition adjustment can be made at engine In Figure 42 the Spark Advance with the engine start-up using the software Service Tool.
  • Page 127 - 1 degree of the distributor rotation would produce a 2 degree change in spark timing. G643E engine senses crank position from the crank position sensor and the target wheel. Rotating the distributor will not directly affect ignition timing, except in extreme conditions.

  • Page 128: Charging System

    Charging System Alternators The alternators used on these engines have three General Description phase, full-wave, rectified output. They are the brush type. Refer to the Alternator Coverage chart for The alternator is an electrical and mechanical detailed systems operation information components driven by a belt from engine rotation.

  • Page 129: Troubleshooting

    Troubleshooting Charging system defect is almost caused by lack of pan belt tension and faulty function of wiring, connector, and voltage regulator. One of most important thing during troubleshooting of charging system is determining the reason between overcharging and lack of charging. So, prior to inspection of alternator, check the battery for charging.
  • Page 130 Refer to the following troubleshooting table Symptom Possible cause Remedy Fuse cut off Replace With ignition switch ON, Bulb burnt out Replace charging warning lamp Loose wiring connection Retighten does not illuminate Bad connection of L terminal Inspect and replace wiring Loose or worn drive belt Correct or replace With the...

  • Page 131: Troubleshooting Procedure

    Troubleshooting Procedure Inspection before Starting 1. Alternator and drive belt tension inspection. G643(E) Service Manual Chapter 4. Engine Electrical System...
  • Page 132 2. Alternator and outer terminal connection inspection. G643(E) Service Manual Chapter 4. Engine Electrical System...
  • Page 133 3. Battery outer terminal inspection. Inspection after Starting 1. When starting, belt slip and noise inspection 13.2~15.4V 2. Inspection of battery voltage at idling (At this time charge battery only) G643(E) Service Manual Chapter 4. Engine Electrical System...
  • Page 134 Drop of Electric Pressure Test of Alternator Test Output Wire 1. Start the engine. This test is to check that wiring is correctly connected between the alternator “B“ terminal and 2. Repeating ON and OFF of headlight and small battery (+) terminal. light, adjust the engine speed until an ammeter reads 20A and at that time measure voltage.
  • Page 135 2. Turn the ignition switch OFF. 3. With the engine running at 2,500 rpm, turn ON the high beam headlights, place the heater blower 3. Disconnect the battery ground cable. switch at ”HIGH” measure the maximum output current using a ammeter. 4.
  • Page 136 STARTING SYSTEM General Description The starting motor is used to turn the engine flywheel lfast enough to make the engine run. The starting motor has a solenoid. When the ignition switch is activated, voltage from the electrical system will cause the solenoid to move the pinion toward the flywheel ring gear of the engine.

  • Page 137: Diagnosis Procedure

    Circuit Diagarm For Starting System Diagnosis Procedure The starting motor solenoid has two functions: 1. Engages the pinion with flywheel. The following simplified procedure is intended to help the serviceman determine if a starting motor 2. Is a high current switch rated about 1000 amps needs to be removed and replaced or repaired.
  • Page 138 The result of these switches and relays is to permit a 5 amp dash-mounted switch to turn on a 500 to NOTICE 1000amp motor used to crank an engine. Battery voltage (power) available during cranking varies Do not operate the starting motor for more than according to the temperature of the batteries.

  • Page 139: Start Relay Tests

    5. Is voltage equal to or greater than shown in Start Relay Tests Figure1? Relay • If the starting motor voltage is correct, the battery and starting motor cables down to the 1. Put the multimeter on the 200 ohm scale. motor are within specifications.
  • Page 140 Troubleshooting Starting system problem can be classified into “Start motor is not operating”, “Start motor is operating but engine is not starting” , and “There is a lot of time taken to start engine”. When the starting system has problems, before removing the start motor, find where the problem happens.

  • Page 141: Installation

    Starter Repair Removal Remove or disconnect WARNING Always disconnect the cable at the battery before you make repairs to the engine. Disconnect the cable at the negative terminal first. Install a tag on the battery terminals first. Install a tag on the battery terminals so that no one connects the cable on the terminal.

  • Page 142: Chapter 5. Engine Management System (Ems)

    Chapter 5. ENGINE MANAGEMENT SYSTEM (EMS) General Information Specifications SECM and Sensor/Switch Inputs Q’ty Components Items Specifications G643E G643 Environmental / Ambient Operating -20 °F to 221°F [-29 °C to 105 °C] Electrical Temperature None None Specifications 8-16 Vdc Operating Voltage...
  • Page 143 Electronic Throttle System Q’ty Components Items Specifications G643E G643 Electronic Throttle Minimum Electrical 1.5 ohms System Resistance of Throttle Actuator G643(E) Service Manual Chapter 5. Engine Management System (EMS)
  • Page 144 20~25 Ω LP Fuel Lock-off Electrical Resistance N-2007 LP Regulator Fuel Supply Pressure 10 psi to 250 psi (68.95 kPa to For G643E 1723.69 kPa) Fuel Inlet Fitting 1/4” NPT Fuel Outlet Fitting Two 3/4” NPT fittings with one plugged and one 1/8”...
  • Page 145 Q’ty Components Items Specifications G643E G643 N-2001 LP Regulator Fuel Supply Pressure 10 psi to 250 psi (69 kPa to 1724 kPa) For G643 Fuel Inlet Fitting 1/4” NPT Fuel Outlet Fitting One 3/4” NPT and one 1/8” NPT fitting...
  • Page 146 Q’ty Components Items Specifications G643E G643 CA100 Mixer Fuel For G643 Fuel Inlet Fitting 1/2” NPT Fuel inlet fitted with Delphi temperature sensor Air Intake Flange 2.25” (57.15mm) ID inlet, four #10- 24 screws in 1.94” (49.28mm) square pattern Mixer Mounting Flange 1.87”...

  • Page 147: Component Location

    Component Location LP Fuel Lock-off Engine Control Module (SECM48) TMAP Sensor Crankshaft Position Sensor Coolant Temperature Sensor LP Fuel Temperature Sensor G643(E) Service Manual Chapter 5. Engine Management System (EMS)
  • Page 148 Pre-Catalyst Oxygen Sensor Post-Catalyst Oxygen Sensor Pedal Angle Sensor Engine Oil Pressure Switch Ground Speed limit (option) – Sensor Ground speed limit (option) - Controller G643(E) Service Manual Chapter 5. Engine Management System (EMS)
  • Page 149 Electronic Throttle Body Fuel Trim Valve(FTV) Ignition Coil Distributor N-2007 LP Regulator CA100 Mixer G643(E) Service Manual Chapter 5. Engine Management System (EMS)

  • Page 150: General Description

    [Figure 1] MI-07 LP Fuel System for G643E Engine The SECM makes any necessary corrections to the connecting the accelerator pedal to the electronic air fuel ratio by controlling the inlet fuel pressure to throttle through the electrical harness; mechanical the air/fuel mixer by modulating the dual fuel trim cables are not used.
  • Page 151 LP Fuel System of G643E (certified engine system) INPUT OUTPUT Crank Sensor Throttle body TMAP sensor lgnition module (built in Distributor) Coolant Temp 2 Fuel trim valves EG oil pressure switch LP fuelock valve T/M Temp switch CAN communication SECM...
  • Page 152 G643 (E) engine operating on LP fuel. • Small engine control module (SECM), firmware and calibration † Q’ty DESCRIPTION G643E G643 • Fuel system sensors and actuators Engine Control Module (SECM) • Ignition system including spark plugs, cables, coils...

  • Page 153: Lpg Fuel System Operation

    • Fixed-speed isochronous governing with three Limp Home Mode switch-selectable speeds The system is capable of "limp-home" mode in the event of particular faults or failures in the system. In • Fuel enrichment and spark timing modifiers for limp-home mode the engine speed is approximately temperature and fuel type 1000 rpm at no load.
  • Page 154 Dual Dither Valve SECM The key to meeting emissions requirements when The Small Engine Control Module (SECM) controls operating in LPG is the dual dither valve hardware in the LPG lock-off solenoid valve and the FTVs. The the fuel system. Similar to the MI-04 system, the lock-off solenoid is energized when fueling with LPG dual dither system modulates the fuel pressure...
  • Page 155 the Run state, when the engine reaches pre-idle rpm. MI-07 Fuel Lock-Off (Electric) When an operator turns on the key switch the lock- off is opened, but if the operator fails to crank the The fuel lock-off is a safety shutoff valve, normally engine the SECM will close the lock-off after 5 held closed by spring pressure, which is operated by seconds.
  • Page 156 Liquid propane must be converted into a gaseous When the engine is cranking or running a negative form in order to be used as a fuel for the engine. pressure signal (vacuum) travels through the vapor When the regulator receives the desired vacuum fuel outlet connection of the regulator, which is the signal it allows propane to flow to the mixer.
  • Page 157 CA100 Mixer The mixer is installed above the throttle body and meters gaseous fuel into the airstream at a rate that is proportional to the volumetric flow rate of air. The ratio between volumetric airflow and volumetric fuel flow is controlled by the shaping of the mixer fuel cone and biased by the controllable fuel supply pressure delivered by the pressure regulator.
  • Page 158 A pressure/force imbalance begins to build across A main mixture adjustment valve on the fuel inlet of the air valve diaphragm between the air valve the CA100 is not used in the MI-07 system, however vacuum (AVV) chamber (above the diaphragm) and an idle mixture adjustment is incorporated into the atmospheric pressure...
  • Page 159 Fuel Trim Valve (FTV) The Fuel Trim Valve (FTV) is a two-way electric solenoid valve and is controlled by a pulse-width modulated (PWM) signal provided by the SECM. Two FTVs are used to bias the output fuel pressure on the LPG regulator/converter (N-2007), by metering valve vacuum...
  • Page 160 Branch-Tee Fitting secondary diaphragm, which lowers the reference A branch-tee fitting is installed in the atmospheric pressure, closing the N-2007 secondary valve and vent port of the N-2007 with one side of the branch- leaning the air/fuel mixture. The MI-07 system is tee connected to the intake side of the mixer forming calibrated to run rich without the FTV.

  • Page 161: Electronic Throttle System

    Electronic Throttle System MI-07 Electronic Throttle Conventional throttle systems rely on a mechanical linkage to control the throttle valve. To meet The electronic throttle system controls engine output fluctuating engine demands a conventional system (speed and torque) through electronic control of will typically include a throttle valve actuator mass airflow to the engine.
  • Page 162 There are multiple limp-home modes available with Ignition System Control electronic throttle control: Spark-ignited engines require accurate control of 1. If the throttle itself is suspected of being spark timing and spark energy for efficient inoperable, the SECM will remove the power to combustion.
  • Page 163 The MI-07 system is capable of operating with either Exhaust System a distributor based ignition system or a distributorless ignition system. The current Heated Exhaust Gas Oxygen Sensors (HEGO) application uses a distributor based ignition system. The MI-07 system utilizes two HEGO (O2) sensors. The distributor will have no internal advance One sensor is a pre-catalyst sensor that detects the mechanisms giving the SECM consistent authority...
  • Page 164 The HEGO stoichiometric air-fuel ratio voltage target over a platinum and palladium catalyst. Cerium is is approximately 500 mV and changes slightly as a also used to promote oxygen storage and improve function of speed and load. When the pre-catalyst oxidation efficiency.
  • Page 165 SECM position sensor (TPS), and the accelerator pedal position sensors (APP1 & APP2). General Description The SECM provides a transducer ground for all the The Small Engine Control Module (SECM) controller sensors, and a low side driver signal controlling the has full authority over spark, fuel and air.
  • Page 166 The SECM makes any necessary corrections to the air-fuel ratio by controlling the inlet fuel pressure to the air-fuel mixer Reducing the fuel pressure leans the air/fuel mixture and increasing the fuel pressure enriches the air-fuel mixture. Control is achieved by modulating the fuel trim valves.
  • Page 167 Drive-By-Wire Signal Flow Process Figure 21. Peak Torque and Power Available with MI-07 System Figure 22. Drive-By-Wire Signal Flow Process Figure 22 describes the signal flow process of the MI-07 DBW section. The foot pedal assembly uses two potentiometers to detect pedal position. These two signals, accelerator pedal position 1 (APP1) and accelerator pedal position 2 (APP2) are sent directly to the SECM.
  • Page 168 SECM Wiring Diagrams for G643E Ignition Management In the normal course of events, with the engine CAUTION—PROPER WIRING operating at the correct temperature in defined To prevent system faults be sure to follow good conditions, the SECM will use load and engine wiring practices.
  • Page 169 FUELPMP_LS 05_A13 B23_AN2_TPS1 COLOR B4_AN3_TPS2 COLOR A18_H1-_ETC_TB- BLACK COLOR A17_H1+_ETC_TB+ COLOR O2A+_AN11_B13 COLOR COLOR A20_LSO7_O2B_HTR COLOR COLOR BLACK O2B+_AN12_B19 COLOR COLOR CONNECTOR CONNECTOR Figure21. SECM Wiring Diagram for G643E LP Fuel G643(E) Service Manual Chapter 5. Engine Management System (EMS)

  • Page 170: System Overview

    G643 EMS (Engine Management System) Overview General Description MI-04 control system provides a complete, fully Engine speed is monitored by the SECM through a integrated engine management system for naturally variable reluctance (VR) sensor. Intake manifold air aspirated engines. temperature and absolute pressure are monitored with a TMAP sensor.
  • Page 171 LP System of G643 INPUT OUTPUT Speed pick-up in Throttle body Distributor lgnition Module TMAP sensor Coolant Temp EG oil pressure switch SECM LP fuelock valve Accel pedal angle sensor CAN communication Throttle position sensor Ground speed limit Device G643(E) Service Manual Chapter 5.
  • Page 172 • Min/max governing MI-07 System Components • All-speed isochronous governing The MI-07 control system provides electronic control to the following subsystems on mobile industrial • Fixed-speed isochronous governing with three engines: switch-selectable speeds • Spark-ignition control system • Spark timing modifiers for temperature and fuel type •...
  • Page 173 The LP fuel lock-off of G643 engine is the same as and are OEM customer specific. that of G643E engine. See, “G643E EMS overview” N-2001 Regulator/Converter Service Tool After passing through the electric fuel lock-off, liquid...
  • Page 174 the regulator. Heat provided by this coolant is transferred through to the fuel vaporization chamber. Figure 5 shows the heat chamber and the coolant passage in the N-2001 regulator. Figure 6. Parts View of N-2001 Regulator Since the fuel pressure has been reduced from tank pressure to 1.5 psi (10.342 kPa) the liquid propane vaporizes.
  • Page 175 CA100 Mixer The mixer is installed above the throttle body and meters gaseous fuel into the airstream at a rate that is proportional to the volumetric flow rate of air. The ratio between volumetric airflow and volumetric fuel flow is controlled by the shaping of the mixer fuel cone and biased by the controllable fuel supply pressure delivered by the pressure regulator.
  • Page 176 Electronic Throttle System Figure 10. Bottom View of Air Valve Assembly The electronic throttle system of G643 engine is the same as that of G643E engine. See, “Electro-nic throttle system of G643E EMS overview” Figure 11. CA100 Mixer Installed with Electronic...
  • Page 177 GM Delco EST Ignition System Ignition System The MI-07 system is capable of operating with either Spark-ignited engines require accurate control of a distributor based ignition system or a spark timing and spark energy for efficient distributorless ignition system. The current combustion.
  • Page 178 The SECM monitors system parameters and stores any out of range conditions or malfunctions as faults in SECM memory. Engine run hours are also stored in memory. Stored fault codes can be displayed on the Malfunction Indicator Light (MIL) as flash codes or read by the Service Tool software through a CAN (Controller Area Network) communication link.
  • Page 179 A Throttle Position Sensor (TPS), (Figure 18) which is integral to the Drive By Wire (DBW) throttle assembly, provides feedback for position control by monitoring the exact position of the throttle valve. NOTE: The DV-E5 is not a serviceable assembly. If the TPS sensor fails, the assembly should be replaced.

  • Page 180: Ignition Management

    Figure 21. Drive-By-Wire Signal Flow Process MI-07 Ignition Management (Figure 21) describes the signal flow process of the MI-07 DBW section. The foot pedal assembly uses two potentiometers to detect pedal position. These In the normal course of events, with the engine two signals, accelerator pedal position 1 (APP1) and operating at the correct temperature in defined accelerator pedal position 2 (APP2) are sent directly...
  • Page 181 SECM Wiring Diagrams for G643 LP Engine G643(E) Service Manual Chapter 5. Engine Management System (EMS)
  • Page 182 G643(E) Service Manual Chapter 5. Engine Management System (EMS)

  • Page 183: Ems Inspection And Repair

    EMS Inspection and Repair -40°F to 266°F (-40ºC to 130ºC) range, 48K ohm to 57 ohm sensor range Engine Control Module[G643E] • HEGO (3) 0 to 1 V The 48-pin Small Engine Control Module (SECM) • Auxiliary Analog Input (2) 0 to 5 V...
  • Page 184 Crank Shaft Position Sensor [G643E] Outputs • Saturated injector drivers (4) Component Location 10A peak, 45 V max, 1 injector per channel capable of continuous on-time Driver circuit designed for minimum turn-on/turn- off delay Minimum pulse width resolution of 1 usec •...
  • Page 185 MAP (Manifold Absolute Pressure) Schematic Diagram for G643E Sensor [G643E and G643] Sensor Inspection MAP sensor The manifold absolute pressure (MAP) sensor is a pressure sensitive variable resistor. It measures changes in the intake manifold pressure which result from engine load and speed changes, and converts this to a voltage output.

  • Page 186: Iat (Intake Air Temperature) Sensor

    Verify that the connector clicks/locks into place. 3. Connect the negative battery cable. IAT (Intake Air Temperature) Sensor [G643E and G643] Sensor Inspection 1. Measure the voltage between terminals 1 and 4 of MAP sensor the MAP sensor connectors.
  • Page 187 OxygenSensor (Pre-Catalyst) [G643E] Circuit Diagram (G643) Component Location Pre - Catalyst Oxygen Sensor Description The heated oxygen sensor is mounted on the front side of Catalytic Muffler, which detects the oxygen concentration in the exhaust gas. The heated Sensor Inspection oxygen sensor produces a voltage that varies between 0V and 1V.
  • Page 188 Schematic Diagram (G643E) Oxygen Sensor (Post-Catalyst) [G643E] Component Location [CIRCUIT DIAGRAM] HO2S (B1/S1) A23 - HO2S HEATER (B1/S1) B13 - HO2S SIGNAL B1 - HO2S GND After Main Relay [HARNESS CONNECTORS] Description The rear heated oxygen sensor is mounted on the rear side of the Catalytic Muffler, which detects the catalyst efficiency.

  • Page 189: Specification

    2. With the temperature sensing portion of the engine coolant temperature sensor immersed in hot water, check resistance. ECT (Engine Coolant Temperature) Sensor [G643E and G643] Temperature ℃ (℉) ECTS Resistance(kΩ) 20(68) 2.31~2.59 Component Location 3.
  • Page 190 Installation Schematic Diagram (G643E) 1. Install engine coolant temperature sensor and tighten it to specified torque. Tightning torque Engine coolant temperature sensor " 15~20Nm (150~200 kg· cm, 11~15 lb· ft) 2. Connect the harness connector securely. [HARNESS CONNECTORS] Schematic Diagram (G643) G643(E) Service Manual Chapter 5.
  • Page 191 LP Fuel Temperature Sensor [G643E] [Harness Connectors] Location Inspection Description 1. Remove the LP fuel temperature sensor from the The LP Fuel Temperature Sensor (FTS) is located in adapter connected to LP mixer. the LP fuel passage of the LP mixer for detecting the LP fuel temperature.
  • Page 192 Angle Sensor-Accelerator [G643E and G643] Circuit Diagram (G643) Location [Harness Connectors] Description Angle Sensor-Accelerator located accelerator pedal assembly. The engine speed management deals with a Drive-by-wire system. Drive-by-wire refers to the fact that the MI-07 control system has no throttle cable from the foot pedal to the throttle body.
  • Page 193 1. Remove the Transmission Oil Temperature Switch from the transmission. 2. Use an ohmmeter to check the continuity between Circuit Diagram [G643E] the 1 terminal and the 2 terminal. If there is continuity, replace the Transmission Oil Temperature Switch.
  • Page 194 Circuit Diagram [G643] Electronic Throttle Body [G643E and G643] Location [Harness Connectors] Description The MI-07 system uses electronic throttle control (ETC). The SECM controls the throttle valve based on engine RPM, engine load, and information received from the foot pedal. Two potentiometers on the foot pedal assembly monitor accelerator pedal travel.

  • Page 195: Chapter 6. Lpg Fuel Delivery System

    Chapter 6. LPG FUEL DELIVERY SYSTEM G643E LP System Inspection and Repair Removal and Installation WARNING - PROPER USE • LP gas is highly flammable. To prevent personal injury, keep fire and flammable mate- rials away from the lift truck when work is done on the fuel system.

  • Page 196: Hose Connections

    Hose Connections Proper operation of the closed loop control greatly depends on the correct vacuum hose routing and fuel line lengths. Refer to the connection diagrams below for proper routing and maximum hose lengths when reinstalling system components. NOTE: Preferred mounting of regulator is off engine. Hose Specifications Vacuum hose to comply to SAE 1403 Type I or SAE J30 R7 R8 / EPDM textile reinforced / -40°...
  • Page 197 DIAGRAM NOTES Trim valves must be positioned N-2007 Regulator Solenoid (AFS Lock Off Valve) vertically with flow arrows in position Plastic WYE Fitting (black color) Brass Tee Fitting. 1/4 Tube x 1/8 shown for 7/32” (5.56mm) ID Tube NPTF x 1/4 Tube Fuel outlet must be min 15°...

  • Page 198: Removal And Installation Of N-2007 Lp Regulator

    N-2007 Installation Steps Removal and Installation of N-2007 LP Regulator Refer to Figure 28. Follow the procedures below for removal and 1. Install the nipple extension (6) with the lock-off to reinstallation of the N-2007 regulator in certified the regulator. systems.
  • Page 199 3. Key switch in “OFF” position. Removal and Installation of CA100 Mixer for G643E 4. Remove the air cleaner hose (1). Follow the procedures below for removal and reinstallation of the CA100 mixer. 5. Mark the two vacuum lines (2) to the mixer for...
  • Page 200 NOTE: A plastic O-ring spacer and an O-ring are CA100 Certified Mixer Installation Steps inside the mixer/adapter assembly. Be careful not to lose these items when removing the assembly from Refer to Figure 30. the throttle (Figure 31). 1. Install the vacuum port barb onto the mixer (9). Wiring harress connection 2.

  • Page 201: Tests And Adjustments

    Tests and Adjustments N-2007 Regulator Service Testing For checking the N-2007 regulator/converter WARNING—PROPER USE operation, the following tests can be performed (See Chapter 5 for removal/installation of the N-2007 • LP gas is highly flammable. To prevent perso- regulator). To check the secondary regulation nal injury, keep fire and flammable materials (output) a simple vacuum hand pump can be used away from the lift truck when work is done on...
  • Page 202 3. Apply compressed air, wait for air to exit the hose barb in the test port, and then connect the Magnehelic gauge (Figure 36) to the hose barb using the vacuum hose or vinyl tubing. This prevents the gauge from reading maximum pressure due to the large velocity of compressed air entering the primary chamber.

  • Page 203: Avv (Air Valve Vacuum) Testing

    5. If the measured pressure drop is low, check for vacuum leaks in the manifold, throttle, mixer, CAUTION TMAP sensor and attached hoses. • LP gas is highly flammable. To prevent personal injury, keep fire and flammable mate- rials away from the lift truck when work is done on the fuel system.
  • Page 204 6. If present, set fuel select switch to LPG fuel. When operated at the factory, it is critical to simulate the airflow found on a forklift at idle as nearly as possible in order to achieve the proper air valve lift in the mixer.
  • Page 205 14. Use the accelerator pedal to increase RPM Field Adjustment Procedure: above idle momentarily (rev the engine) then release the pedal to return to idle RPM. The duty The idle mixture adjustment should only be cycle setting should remain within the adjustment necessary on a new mixer that does not have the range (50-55%).
  • Page 206 8. If the FTV duty cycle reading is above 55% adjust the idle adjustment screw outward and re-check the duty cycle reading. Continue to do this until the FTV duty cycle reading is within the optimum range (45-55%). DO NOT adjust the screw so far outward that the tamper proof cap cannot be installed.

  • Page 207: Parts Description

    Parts Description CA100 Mixer for G643E Engine Parts List of CA100 Mixer (Certified) REF NO DESCRIPTION Torx Screws (T-25) #10-24 x 5/8” Lockwashers (T-210) #10 SST Mixer Cover Mixer Spring Diaphragm Air Valve Assembly Gas Valve Cone (part of air valve assembly) Mixer Body Expansion Plug Cap Ø...
  • Page 208 Exploded View of CA100 Mixer (Certified) Figure 44. CA100 Certified Mixer Exploded View G643(E) Service Manual Chapter 6. LPG FUEL DELIVERY SYSTEM...
  • Page 209 N-2007 Regulator for G643E Engine Parts List of N-2007 Regulator (Certified) REF NO DESCRIPTION N-2007 Body Diaphragm, Primary Assembly Springs, Primary Assembly Cover, Primary Assembly Spring, Secondary Seat, Red Dowel Pin Ø 0.094” x 1” L (Ø 2.39mm x 25.4mm L) Hardened Steel...
  • Page 210 Exploded View of N-2007 Regulator (Certified) Figure 46. N-2007 Certified Regulator Exploded View G643(E) Service Manual Chapter 6. LPG FUEL DELIVERY SYSTEM...
  • Page 211 G643 LPG System Inspection and Repair Removal and Installation WARNING – PROPER USE • LP gas is highly flammable. To prevent perso- nal injury, keep fire and flammable materials away from the lift truck when work is done on the fuel system. •...
  • Page 212 Hose Connections Proper operation of the closed loop control greatly depends on the correct vacuum hose routing and fuel line lengths. Refer to the connection diagram below for proper routing and maximum hose lengths when reinstalling system components. NOTE: Preferred mounting of regulator is off engine. Hose Specifications Vacuum hose to comply to SAE 1403 Type I or SAE J30 R7 R8 / EPDM textile reinforced / -40˚...

  • Page 213: Removal And Installation Of N-2001 Lp Regulator/Converter

    Removal and Installation of N-2001 LP Regulator/Converter Follow the procedures below for removal and reinstallation of the N-2001 regulator. N-2001 Removal Steps Refer to Figure 29. 1. Close the liquid outlet valve in the forklift cylinder or fuel storage container. Figure 29.
  • Page 214 Removal and Installation of CA100 Mixer for G643 Follow the procedures below for removal and reinstallation of the CA100 mixer in non-certified systems. CA100 Mixer Removal Steps Figure 33. CA100 Mixer in Non-Certified System 12-01 1. Close the liquid outlet valve in the forklift cylinder or fuel storage container.
  • Page 215 CA100 Mixer Installation Steps NOTE : A plastic O-ring spacer and an O-ring are inside the mixer/adapter assembly. Be careful not to lose these items when removing the assembly from 1. Install the vapor fuel inlet fitting onto the mixer. the throttle (Figure 31).
  • Page 216 Tests and Adjustments Secondary Stage (Break-Off) Test 1. Connect the vacuum pump, the Magnehelic gauge and the regulator vapor outlet to the Union WARNING – PROPER USE Tee fitting (Figure 30). Make sure there is no leakage at any of the fittings. •...
  • Page 217 Pressure Test Primary Stage Pressure Test Primary Stage Test Hardware 1. Remove the primary test port plug from the side of the regulator and install the 1/16” NPT hose barb fitting (Figure 31). 1. Hand vacuum pump 2. Connect a compressed air line (shop air ~100 psi) 2.
  • Page 218 AVV (Air Valve Vacuum) Testing Idle Mixture Adjustment Purpose of Test NOTE : Be sure engine is fully warm (ECT>167°F [75°C]) before performing idle mixture adjustment. Check for excessive or inadequate pressure drop across CA100 mixer. G643 LP Fuel Systems with O2 Sensor AVV Test Hardware Idle Adjustment 1.
  • Page 219 Power Valve Adjustment Power Valve Adjustment 1. The power valve should only be adjusted after the 1. The power valve should only be adjusted after the idle screw has been adjusted properly. The idle screw has been adjusted properly. The engine and vehicle drive train and hydraulics engine and vehicle drive train and hydraulics should also be at normal operating temperatures.
  • Page 220 Parts Description CA100 Mixer for G643 Engine Refer to Figure 45 exploded view on facing page. REF NO. DESCRIPTION Screws 10-24 x 5/8” T-25 Button Head SEMS Mixer Cover Mixer Spring Diaphragm Gas Valve Cone (part of air valve assembly) Mixer Throttle Body Gasket Screws 12-24 x 5/8”...
  • Page 221 Exploded View CA100 Mixer Figure 44. CA100 Non-Certified Mixer Exploded View G643(E) Service Manual Chapter 6. LPG FUEL DELIVERY SYSTEM...

  • Page 222: Ca100 Disassembly And Service

    CA100 Disassembly and Service Figure M4 1. With the mixer/adapter assembly removed from the engine, and the throttle adapter removed from the mixer, remove the four cover retaining screws from the top of the mixer (Figure M4). Figure M5 2. Gently remove the diaphragm cover from the top of the mixer.

  • Page 223: Ca100 Disassembled Service

    CA100 Disassembled Service 1. Clean the air valve assembly with soap and warm water to remove heavy-end deposits. Inspect the fuel metering valve and sealing ring for wear. Replace worn components as necessary. Replace all gaskets before assembly. Clean the mixer body (casting) with a parts cleaning solvent.
  • Page 224 N-2001 Regulator for G643 Engine Refer to Figure 47 exploded view on facing page. Parts List N-2001-RSA Regulator REF NO. DESCRIPTION Cover Screws 8-32 x 5/8” SEMS Torx Screws (T-15) 8-32 x 5/8” Tamper Resistant Lockwasher #8 Internal Tooth Secondary Cover Secondary Diaphragm Assembly Pan Head Screw 10-24 x 1/4”...
  • Page 225 Exploded View N-2001-RSA Regulator Figure 47. N-2001 Regulator Exploded View G643(E) Service Manual Chapter 6. LPG FUEL DELIVERY SYSTEM...

  • Page 226: N2001 Regulator Disassembly Steps

    N2001 Regulator Disassembly Steps: Figure R5 Figure R3 Figure R5 Remove the six primary diaphragm cover screws (4) Figure R4 and the primary cover assembly (5). 1. Remove the six secondary cover screws (1), the secondary cover (2) and the secondary diaphragm (3).
  • Page 227 Figure R7 6. Remove the body gasket (10), body o-ring seal (11) and the fuel inlet plate, exposing the fuel inlet expansion chamber and the coolant passage. NOTE For re-assembly of the N2001 regulator/converter, reverse the steps for disassembly. Tighten all fasteners to recommended torque values and test the regulator before installing in the vehicle.

  • Page 228: N2001 Disassembled Service

    N2001 Disassembled Service 1. Clean the primary and secondary valves with soap and warm water to remove heavy-end deposits. Inspect the valve seats and o-rings for wear. Replace worn components as necessary. 2. Clean the primary and secondary diaphragms with soap and warm water. Inspect for wear, tears or pinholes and deformations that may cause leaks or poor performance of the regulator/converter.

  • Page 229: Chapter 7. Basic Troubleshooting

    Chapter 7. BASIC TROUBLESHOOTING Preliminary Checks Visual/Physical check Several of the procedures call for a “Careful MI-07 systems are equipped with built-in fault Visual/Physical Check” which should include: diagnostics. Detected system faults can be displayed by the Malfunction Indicator Lamp (MIL) •...

  • Page 230: Customer Problem Analysis Sheet

    Basic Troubleshooting Guide Customer Problem Analysis Sheet 1. Forklift Information (I) VIN: (II) Production Date: (III) Hour meter Reading: (hrs) 2. Symptoms □ Engine does not turn over □Incomplete combustion □ Unable to start □ Initial combustion does not occur □...

  • Page 231: Basic Inspection Procedure

    Basic Inspection Procedure 4. Repair or replace the component that has a problem. Measuring Condition Of Electronic Parts 5. Verify that the problem has disappeared with the Resistance road test. The measured resistance at high temperature after • SIMULATING VIBRATION vehicle running may be high or low.

  • Page 232: Connector Inspection Procedure

    Connector Inspection Procedure Handling of Connector 4. When a tester is used to check for continuity, or to measure voltage, always insert tester probe from wire harness side. 1. Never pull on the wiring harness when disconnecting connectors. 5. Check waterproof connector terminals from the connector side.
  • Page 233 Checking Point for Connector Wire Harness Inspection Procedure 1. Before removing the wire harness, check the wire harness position and crimping in order to restore it correctly. 2. Check whether the wire harness is twisted, pulled or loosened. 3. Check whether the temperature of the wire harness is abnormally high.
  • Page 234 Electrical Circuit Inspection Procedure normal). To find exact break point, check sub line of line 1as described in next step. • Check Open Circuit b. Disconnect connector (B), and measure for 1. Procedures for Open Circuit resis tance between connector (C) and (B1) and between (B2) and (A) as shown in [FIG.3].
  • Page 235 • Check Short Circuit b. Disconnect connector (B), and measure the resistance between connector (A) and chassis ground, and between (B1) and chassis ground 1. Test Method for Short to Ground Circuit as shown in [FIG.7]. • Continuity Check with Chassis Ground The measured resistance between connector (B1) If short to ground circuit occurs as shown in [FIG.5], and chassis groundis1Ω...
  • Page 236 Basic Troubleshooting An intermittent “Service Engine Soon” light with no stored diagnostic code may be caused by: Intermittents • Ignition coil shortage to ground and arcing at spark plug wires or plugs An intermittent fault is the most difficult to troubleshoot since the MIL flashes on at random, •...

  • Page 237: Surges And/Or Stumbles

    Surges and/or Stumbles Engine power varies under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the acceleration pedal. Preliminary Checks Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. Be sure driver understands vehicle operation as explained in the operator manual.

  • Page 238: Engine Cranking But Will Not Start / Difficult To Start

    Engine Cranking but Will Not Start / Difficult to Start Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies. Preliminary Checks Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. Be sure driver is using correct method to start engine as explained in operator’s manual.
  • Page 239 Engine Cranking but Will Not Start / Difficult to Start (cont’d.) PROBABLE CAUSE CORRECTIVE ACTION Check Coolant Temperature Sensor using the Service Tool; compare coolant temperature with ambient temperature on cold engine. If coolant temperature reading is 5° greater than or less than ambient air temperature on a cold engine, check resistance in coolant sensor circuit or sensor itself.
  • Page 240 Lack of Power, Slow to Respond / Poor High Speed Performance / Hesitation During Acceleration Engine delivers less than expected power. Little or no increase in speed when accelerator pedal is pushed down part way. Momentary lack of response as the accelerator is pushed down. Can occur at all vehicle speeds.
  • Page 241 Lack of Power, Slow to Respond / Poor High Speed Performance / Hesitation During Acceleration (cont’d.) PROBABLE CAUSE CORRECTIVE ACTION Check SECM grounds for cleanliness and secure connection. See SECM wiring diagrams. Check alternator output voltage. Repair if less than 9 volts or more than 16 volts.

  • Page 242: Detonation / Spark Knock

    Detonation / Spark Knock A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening (similar to the sound of hail striking a metal roof). PRELIMINARY CHECKS Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. PROBABLE CAUSE CORRECTIVE ACTION Check for proper fuel level:...
  • Page 243 Backfire Fuel ignites in intake manifold or in exhaust system, making loud popping noise. PRELIMINARY CHECKS Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. Simulate condition by reviewing operation procedure practiced by vehicle operator. PROBABLE CAUSE CORRECTIVE ACTION Perform fuel system diagnosis check: •...

  • Page 244: Rough, Unstable, Incorrect Idle, Or Stalling

    Rough, Unstable, Incorrect Idle, or Stalling Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies. PRELIMINARY CHECKS Perform the visual checks as described at start of “Basic Troubleshooting” chapter. Check for vacuum leaks.
  • Page 245 Rough, Unstable, Incorrect Idle, or Stalling (cont’d.) PROBABLE CAUSE CORRECTIVE ACTION Reset excess flow valve. Excess flow valve closed • Close liquid valve. • Wait for a “click” sound. Slowly open liquid valve. Repair/replace as required Clogged fuel filter See Chapter 2 Fuel Filter Replacement Remove obstruction from the fuel line.

  • Page 246: Cuts Out, Misses

    Cuts Out, Misses Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases, sometimes above 1500 rpm. The exhaust has a steady spitting sound at idle or low speed. PRELIMINARY CHECKS Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. PROBABLE CAUSE CORRECTIVE ACTION Check fuel system specifically for plugged fuel filter, low pressure.

  • Page 247: Poor Fuel Economy / Excessive Fuel Consumption / Lpg Exhaust Smell

    Poor Fuel Economy / Excessive Fuel Consumption / LPG Exhaust Smell Fuel economy, as measured during normal operation, is noticeably lower than expected. Also, economy is noticeably lower than what it has been in the past. Propane fuel smell near vehicle sets off carbon monoxide sensors.

  • Page 248: High Idle Speed

    High Idle Speed Engine idles above the range of 750-1100 rpm. PRELIMINARY CHECKS Perform the visual checks as described at start of “ Basic Troubleshooting” chapter. PROBABLE CAUSE CORRECTIVE ACTION Check all hoses and gaskets for cracking, kinks, or leaks. Verify that there are no vacuum leaks.

  • Page 249: Excessive Exhaust Emissions Or Odors

    Excessive Exhaust Emissions or Odors Vehicle has high CO emissions. NOTE: Excessive odors do not necessarily indicate excessive emissions. PRELIMINARY CHECKS Verify that no stored codes exist. If emission test shows excessive CO and HC, check items that cause vehicle to run rich. If emission test shows excessive NOx, check items that cause vehicle to run lean or too hot.

  • Page 250: Diagnostic Aids For Rich / Lean Operation

    Diagnostic Aids for Rich / Lean Operation SERVICE TOOL ITEM RICH LEAN Pre-catalyst O2 A/ D counts Consistently > 250 Consistently < 170 Pre-catalyst O2 sensor switching Always high ADC Always low ADC between high and low Trim valve duty cycle >...
  • Page 251 Chart T-1 Restricted Exhaust System Diagnosis: Check 1. With the engine idling at normal operating temperature, observe the exhaust system Proper diagnosis for a restricted exhaust system is backpressure reading on the gage. Reading essential before replacement of any components. should not exceed 1.25 psig (8.61 kPa).

  • Page 252: Chapter 8. Advanced Diagnostics

    Reading Diagnostic Fault Codes position you must cycle the foot pedal by depressing it to the floor and then fully releasing the pedal G643E Engines (pedal maneuver). You must fully cycle the foot pedal three (3) times within five (5) seconds to All fault codes are three-digit codes.

  • Page 253: Fault Action Descriptions

    Fault Action Descriptions Fault List Definitions Each fault detected by the SECM is stored in All the analog sensors in the MI-07 system have memory (FIFO) and has a specific action or result input sensor range faults. These are the coolant that takes place.

  • Page 254: Lpg And Lpg Fuel Tanks

    Appendix water to remain in liquid state at the engines operating temperature. LPG And LPG Fuel Tanks The same principle is applied to LPG in a container, commonly referred to as an LPG tank or cylinder. LPG Fuel Supply Typically an LPG tank is not filled over 80% capacity allowing for a 20% vapor expansion space.

  • Page 255: Installing Lpg Fuel Tanks

    LPG Fuel Tanks Installing LPG Fuel Tanks The two styles of LPG storage containers available When installing a tank on a lift truck, the tank must for industrial use and lift truck applications are be within the outline of the vehicle to prevent portable universal cylinders and permanently damage to the valves when maneuvering in tight mounted tanks.

  • Page 256: Fuel Gauge

    Fuel Gauge Service Valve In figure 5 a visual fuel gauge is used to show the The service valve is a manually operated valve fuel level in the tank. A mechanical float mechanism using a small hand wheel to open and close the fuel detects the liquid propane level.

  • Page 257: Quick Disconnect Coupling

    Filler Valve Most liquid service valves have an internal hydrostatic relief valve and are usually labeled “LIQUID WITH INTERNAL RELIEF”. The The liquid filler valve (Figure 9) has a male thread to hydrostatic relief valve protects the fuel service line receive a fuel nozzle and typically has a plastic or between the tank and the lock off from over brass screw on cap that is retained with a small...

  • Page 258: Regulatory Compliance

    Regulatory Compliance WARNING—EXPLOSION HAZARD EPA / CARB Emissions Certification Do not connect or disconnect while circuit is live unless area is known to be non-hazardous. When properly applied and calibrated, ’s MI-07 control system is capable of meeting EPA 2007 LSI Substitution of components may impair suitabil- emission standards (40 CFR Part 1048.101) when ity for Class I, Division 2, or Zone 2 applications.
  • Page 259 Abbreviations ACFM Actual cubic feet per minute at the specified suction conditions Air fuel ratio Brake horsepower Bi-Fuel Able to operate on either of two fuels Coolant temperature sensor Compressed natural gas Dual Fuel Able to run simultaneously on two fuels, e.g. diesel and natural gas. Often this term is incorrectly used to describe bi-fuel operation.

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