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Vanguard 25E300 Repair Manual

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REPAIR MANUAL
Vanguard
EFI Diagnostics
®
and Repair
25E300

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Summary of Contents for Vanguard 25E300

  • Page 1 REPAIR MANUAL Vanguard EFI Diagnostics ® and Repair 25E300...
  • Page 2 This manual was written to assist engine technicians and service personnel with the troubleshooting and repair procedures for Briggs & Stratton® and Vanguard® engines equipped with Electronic Fuel Injection (EFI). It assumes that persons using this manual have been properly trained and are familiar with the service procedures for these products, including the proper use of required tools and the application of appropriate safety practices.
  • Page 3 Engine Models Covered This engine repair manual includes the following engine models: • MODEL 25E300 NOTE: Some models have limited service parts. Review the Illustrated Parts List for part availability before conducting any service work. NOTE: Many of the images in this document are representative of the Standard Chore engine. While other engines models may appear somewhat different, unless indicated otherwise, the procedures are the same.
  • Page 4 How To Use This Manual This manual is designed to assist in the diagnostic and troubleshooting process. Troubleshooting of any system follows a similar methodology, in general there are seven steps in the troubleshooting process: Identify the problem. Observe the issue or the symptoms of the issue. Identify the system in which the problem occurs. Create a theory of the probable cause of the problem. Sometimes a problem may have multiple probable causes, in this case, it is necessary to create a plan to test all possibilities to determine the root cause of the problem.
  • Page 5 SECTION 1 - SAFETY AND GENERAL INFORMATION SECTION 2 - DIAGNOSTIC INTRODUCTION SECTION 3 - TROUBLESHOOTING DTCs SECTION 4 - WIRE HARNESS SCHEMATICS AND PIN-OUTS SECTION 5 - SYMPTOMS AND TROUBLESHOOTING GUIDE SECTION 6 - REMOVAL AND INSTALLATION SECTION 7 - SPECIFICATIONS vanguardpower.com...
  • Page 6 SECTION 1 - SAFETY AND GENERAL INFORMATION GENERAL SAFETY MESSAGES ------------------------------------------------------------------------------------------------------------------------ 8...
  • Page 7 • If there is natural or LP gas leakage in the area, do not General Safety Messages start the engine. • Because vapors are flammable, do not use pressurized Prior to work, read and understand the section(s) of this manual that pertain to the job. Follow all safety warnings. starter fluids.
  • Page 8 WARNING  WARNING  Fuel vapors are flammable and explosive. Fire or POISONOUS GAS HAZARD. Engine exhaust contains explosion could result in burns or death. Always observe carbon monoxide, a poisonous gas that could kill you in the following safety precautions before removing any minutes.
  • Page 9 WARNING  WARNING  Rotating parts can entangle hands, feet, hair, clothing, Fuel and its vapors are flammable and explosive. Fire or or accessories and result in traumatic amputation or explosion could result in burns or death. laceration. Fuel Storage • Operate equipment with the guards correctly installed. •...
  • Page 10 SECTION 2 - DIAGNOSTIC INTRODUCTION DIAGNOSTIC INTRODUCTION ------------------------------------------------------------------------------------------------------------------------ 12 Preliminary Instructions ------------------------------------------------------------------------------------------------------------------------------ 12 On-Board Diagnostic (OBD) System Check ----------------------------------------------------------------------------------------------------12 Diagnostic Trouble Codes (DTCs) ---------------------------------------------------------------------------------------------------------------- 12 Malfunction Indicator Lamp (MIL) ----------------------------------------------------------------------------------------------------------------- 12 Data Link Connector (DLC) -------------------------------------------------------------------------------------------------------------------------12 Using the Diagnostic Tool and Software to Read/Clear DTCs ---------------------------------------------------------------------------- 13 Back Probe Connector Terminals -----------------------------------------------------------------------------------------------------------------14 Avoid ECM Damage ---------------------------------------------------------------------------------------------------------------------------------- 14...
  • Page 11 A helpful analogy is to view the SPN as a zip code which Diagnostic Introduction brings you to the problem area, while the FMI is the street address. For example, SPN 105 indicates that an issue exists with the Manifold Air Temperature (MAT) Sensor, while FMI 3 Preliminary Instructions indicates that the sensor signal voltage is high/open.
  • Page 12 Remove the DLC from the wire harness clip (A, Figure Remove the DLC protective cap. Pull out the locking tab (A, Figure 3) and press the connector tab while pulling the protective cap (B) away from the DLC.  NOTE: Make sure to reinstall the DLC protective cap when diagnostic procedures are concluded.
  • Page 13 Turn Ignition ON, Engine OFF. Back Probe Connector Terminals The Diagnostic Tool can take up to 30 seconds to Do not insert probes into terminals on the mating side of connect to the engine. Once established, the connection any connector. The diameter of the test probes can damage indicator light (A, Figure 4) becomes solid green and terminals.

  • Page 14: Table Of Contents

    SECTION 3 - TROUBLESHOOTING DTCs DIAGNOSTIC TROUBLE CODES (DTCS) ---------------------------------------------------------------------------------------------------------- 18 MODEL 25E300 EFI COMPONENT LOCATIONS -------------------------------------------------------------------------------------------------19 PRELIMINARY INSTRUCTIONS ----------------------------------------------------------------------------------------------------------------------- 20 CAN BUS TROUBLESHOOTING ---------------------------------------------------------------------------------------------------------------------- 20 Check Voltages ---------------------------------------------------------------------------------------------------------------------------------------- 20 Check Waveforms ------------------------------------------------------------------------------------------------------------------------------------- 21 TEST PROCEDURES ------------------------------------------------------------------------------------------------------------------------------------- 22 VERIFY ENGINE CONTROL MODULE (ECM) POWERS UP --------------------------------------------------------------------------------- 23...
  • Page 15 Possible FMIs - SPN 110 --------------------------------------------------------------------------------------------------------------------------- 35 SPN 110, FMI 3: Voltage High/Open ------------------------------------------------------------------------------------------------------------ 36 SPN 110, FMI 4: Voltage Low --------------------------------------------------------------------------------------------------------------------- 36 SPN 158 IGNITION KEY VOLTAGE ------------------------------------------------------------------------------------------------------------------ 37 Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 37 Possible FMIs - SPN 158 --------------------------------------------------------------------------------------------------------------------------- 37 SPN 158, FMI 3: Voltage High -------------------------------------------------------------------------------------------------------------------- 37 SPN 158, FMI 4: Voltage Low --------------------------------------------------------------------------------------------------------------------- 38 SPN 168 BATTERY VOLTAGE -------------------------------------------------------------------------------------------------------------------------39...
  • Page 16 SPN 818, FMI 4: Short 5V Supply Low --------------------------------------------------------------------------------------------------------- 50 SPN 1110 ENGINE OVER TEMPERATURE FOR MAXIMUM ALLOWED TIME --------------------------------------------------------- 51 Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 51 Possible FMIs - SPN 1110 ------------------------------------------------------------------------------------------------------------------------- 51 SPN 1110, FMI 0: Head Over Temperature --------------------------------------------------------------------------------------------------- 51 SPN 1268 CYLINDER 1 IGNITION COIL ------------------------------------------------------------------------------------------------------------52 Circuit Description ------------------------------------------------------------------------------------------------------------------------------------- 52 Possible FMIs - SPN 1268 ------------------------------------------------------------------------------------------------------------------------- 52...

  • Page 17: Diagnostic Trouble Codes (Dtcs)

    Diagnostic Trouble Codes (DTCs) Component Description Throttle Position Sensor (TPS) Intermittent Fail Signal Voltage High Signal Voltage Low/Open Analog Speed Lever Signal Voltage High Signal Voltage Low/Open Low Oil Level Sensor Low Oil Level Error Manifold Absolute Pressure (MAP) Sensor Signal Voltage High Signal Voltage Low/Open Intake Air Temperature (IAT) Sensor...

  • Page 18: Model 25E300 Efi Component Locations

    Model 25E300 EFI Component Locations...

  • Page 19: Preliminary Instructions

    SAFETY AND GENERAL INFORMATION - General Safety Preliminary Instructions Messages. Prior to starting any diagnostic, repair or maintenance ALWAYS wear safety glasses and gloves while performing operation. Make sure you are familiar with ALL safety any diagnostic, maintenance or repair operation. warnings and procedures as outlined in SECTION 1 - CAN BUS Troubleshooting Troubleshooting DTCs may not always get to the real source of the problem, as there can be instances where the problem...

  • Page 20: Check Waveforms

    Check Waveforms It is generally recommended that an overall bus check be performed using an oscilloscope. An inexpensive oscilloscope, and a simple multi-meter using the ohmmeter option can give valuable information on the health of the CAN bus. The CAN electrical signals can be viewed by connecting the oscilloscope to terminal C (CAN Hi) and terminal D (CAN Lo) on the DLC.

  • Page 21: Test Procedures

    Test Procedures The Diagnostic Tool can be used to perform a series of actuator tests to check the functionality of specific engine components. These can only be done with the engine not running. These actuator tests confirm the functionality of the specific component actuators.

  • Page 22: Verify Engine Control Module (Ecm) Powers Up

    and ground. Remove and clean battery terminals. While Verify Engine Control Module (ECM) Powers Up terminals may appear clean, corrosion on the inner surfaces can cause a poor connection to ground. Circuit Description - ECM Power Since all EFI components are dependent on proper operation of the ECM, any diagnosis must include checking ECM power Check ECM Power and Ground Step...

  • Page 23: Ecm Connector Loom Cover Removal

    Lightly push loom cover towards terminal end of ECM Connector Loom Cover Removal connector. While maintaining light pressure on the loom cover, Cut and remove cable strap (A, Figure 7). use a small flat blade screwdriver to push latch (B) on each side of terminal end of connector outward away from connector body.

  • Page 24: Spn 51 Throttle Position Sensor (Tps)

    SPN 51 Throttle Position Sensor (TPS) Circuit Description Possible FMIs - SPN 51 The TPS is used for engine control and governing. The TPS The possible FMIs for SPN 51 are as follows: monitors and controls the throttle position under all operating Description conditions.

  • Page 25: Spn 91 Speed Lever

    SPN 91 Speed Lever  NOTE: The engine will default to minimum target engine Circuit Description speed if SPN 91 fault is active. The ECM provides 5 volts power to the throttle on the equipment, vehicle or to the speed control lever on the engine Possible FMIs - SPN 91 operator panel.

  • Page 26: Speed Vs Voltage Table

    Speed vs Voltage Table...

  • Page 27: Spn 91, Fmi 3: Signal Voltage High

    SPN 91, FMI 3: Signal Voltage High Step Action 1. Turn Ignition OFF. Look for throttle control No problem problems on the operator currently exists. 2. Back probe terminal 4 (White/Brown wire) on engine side of the operator panel and/or equipment side. panel connector.

  • Page 28: Spn 91, Fmi 4: Signal Voltage Low/Open

    SPN 91, FMI 4: Signal Voltage Low/Open Step Action 1. Turn Ignition OFF. Go to step 2. No problem currently exists. 2. Back probe terminal 4 (White/Brown wire) on engine side of the operator panel connector. Clear codes. While monitoring voltage, try 3.

  • Page 29: Spn 98 Low Oil Level

    SPN 98 Low Oil Level Circuit Description Possible FMIs The low oil level sensor is mounted within the engine at the The possible FMIs for SPN 98 are as follows: base of the crankcase. The low oil level sensor uses run- sense technology to only detect low oil level after the engine Description is started.

  • Page 30: Spn 102 Manifold Absolute Pressure Sensor (Map)

    SPN 102 Manifold Absolute Pressure Sensor (MAP) Circuit Description Possible FMIs - SPN 102 The MAP sensor continuously monitors intake manifold The possible FMIs for SPN 102 are as follows: pressure to interpret engine work load to provide accurate Description fuel and spark delivery for optimal engine performance.

  • Page 31: Spn 102, Fmi 3: Signal Voltage High

    SPN 102, FMI 3: Signal Voltage High Step Action 1. Turn Ignition OFF. Problem does not exist Reading is above 4.6 volts DC. 2. Back probe terminal D2 (White/Red wire) of ECM Precede to step 2. connector. 3. Connect terminal D2 back probe to red meter test lead on DVOM.

  • Page 32: Spn 105 Intake Air Temperature Sensor (Iat)

    SPN 105 Intake Air Temperature Sensor (IAT)  NOTE: The IAT sensor is part of the TMAP sensor Circuit Description assembly. The sensor assembly is composed of sensing The IAT sensor is used to monitor incoming air temperature elements for the manifold air pressure (MAP) and intake to make dynamic changes to fuel and spark based on air temperature (IAT).

  • Page 33: Spn 105, Fmi 3: Signal Voltage High/Open

    SPN 105, FMI 3: Signal Voltage High/Open Step Action 1. Turn Ignition OFF. Problem does not exist Reading is above 4.6 volts DC. 2. Back probe terminal E4 (Tan/Black wire) of ECM Precede to step 2. connector. 3. Connect terminal E4 back probe to red meter test lead on DVOM.

  • Page 34: Spn 110 Engine Head Temperature Sensor (Eht)

    SPN 110 Engine Head Temperature Sensor (EHT) Circuit Description Possible FMIs - SPN 110 The possible FMIs for SPN 110 are as follows: The EHT sensor uses a thermistor to control signal voltage Description to the ECM. The ECM applies 5 volts on the sensor circuit. Sensor resistance changes as ambient temperature changes, Intermittent Fail which in turn affects the voltage return to the ECM.

  • Page 35: Spn 110, Fmi 3: Voltage High/Open

    SPN 110, FMI 3: Voltage High/Open Step Action 1. Turn Ignition OFF. EHT sensor OK. Reading is above 4.5 volts DC. EHT 2. Back probe terminal E2 (Tan wire) of ECM sensor is bad. connector.   Replace EFI 3. Connect terminal E2 back probe to red meter test wire ...

  • Page 36: Spn 158 Ignition Key Voltage

    SPN 158 Ignition Key Voltage posts with a DVOM, determine the fault associated with the Circuit Description ignition circuit or charging circuit. The EFI system operates with a battery voltage of 9-16 volts. During normal operation, the MIL is illuminated if the voltage Possible FMIs - SPN 158 is above 16 volts (setting FMI 3) or below 9 volts (setting FMI The possible FMIs for SPN 158 are as follows:...

  • Page 37: Spn 158, Fmi 4: Voltage Low

    SPN 158, FMI 4: Voltage Low Step Action 1. Turn Ignition OFF. Go to step 2. Charge or replace battery. 2. Set DVOM to read volts DC. 3. Connect red meter test lead on DVOM to battery positive (+) post. 4. Connect black meter test lead on DVOM to ground. 5.

  • Page 38: Spn 168 Battery Voltage

    SPN 168 Battery Voltage posts with a DVOM, determine the fault associated with the Circuit Description ignition circuit or charging circuit. The EFI system operates with a battery voltage of 9-16 volts. During normal operation, the MIL is illuminated if the voltage Possible FMIs - SPN 168 is above 16 volts (setting FMI 3) or below 9 volts (setting FMI The possible FMIs for SPN 168 are as follows:...

  • Page 39: Spn 168, Fmi 4: Voltage Low

    SPN 168, FMI 4: Voltage Low Step Action 1. Turn Ignition OFF. Go to step 2. Charge or replace battery. 2. Set DVOM to read volts DC. 3. Connect red meter test lead on DVOM to battery positive (+) post. 4.

  • Page 40: Spn 190 Engine Overspeed Detection

    Possible FMIs - SPN 190 SPN 190 Engine Overspeed Detection The possible FMIs for SPN 190 are as follows: Description Circuit Description The ECM monitors engine speed for overspeed detection. If Over Speed Detected an engine overspeed event is detected, and actively engaging FMI 15: Verify that top no load engine speed is operating at the rev limiter, a fault will be triggered and the MIL will flash.

  • Page 41: Spn 633 Vapor Detection In Fdi

    SPN 633 Vapor Detection in FDI Circuit Description Possible FMIs - SPN 633 The ECM monitors the fuel injector pulse width (the amount of The possible FMIs for SPN 633 are as follows: time the fuel injector is energized or open) to detect vapor in Description the injector.

  • Page 42: Spn 636 Crankshaft Wrong Tooth Number

    SPN 636 Crankshaft Wrong Tooth Number Circuit Description Possible FMIs - SPN 636 The CKP sensor works in conjunction with the 23X reluctor The possible FMIs for SPN 636 are as follows: target wheel on the flywheel. Each tooth on the reluctor wheel is equally spaced with 1 tooth missing for the reference Description sync pulse.

  • Page 43: Spn 637 Missing Crank Sensor (Ckp)

    SPN 637 Missing Crank Sensor (CKP) With the spark under control of the ECM, the engine will not Circuit Description run if the CKP sensor signal is lost. The ECM will not be able The CKP sensor works in conjunction with the 23X reluctor to determine which stroke the pistons are on.

  • Page 44: Spn 639 Can Bus Offline

    Possible FMIs - SPN 639 SPN 639 CAN BUS Offline The possible FMIs for SPN 639 are as follows: Description Circuit Description Data Error The ECM monitors the CAN bus for communication between devices. If expected CAN bus communication is lost, SPN 639 will be stored in the ECM.

  • Page 45: Spn 651 Fuel Injector

    SPN 651 Fuel Injector NOTE: If an ignition coil fault code is active, the fuel injector is Circuit Description turned off. The ECM controls the fuel injector by pulse width modulating the voltage to the injector. If the ECM detects the fuel injector Possible FMIs - SPN 651 voltage signal is not within the expected range, a fuel injector The possible FMIs for SPN 651 are as follows:...

  • Page 46: Spn 651, Fmi 3: Voltage High/Open

    SPN 651, FMI 3: Voltage High/Open Step Action 1. Perform the Injector Cylinder 1 Firing Test. See TEST PROCEDURES in this Problem does not currently exist. Go to step 2. section. 2. Did the test Pass? 1. Turn Ignition OFF. Replace fuel injector.

  • Page 47: Spn 651, Fmi 4: Voltage Low

    SPN 651, FMI 4: Voltage Low Step Action 1. Perform the Injector 1 Firing Test. See TEST PROCEDURES in this section. Problem does not currently exist. Go to step 2. 2. Did the test Pass? 1. Turn Ignition OFF. No problem. Go to step 3.

  • Page 48: Spn 818 Voltage Protection

    event. However, the system temperature may increase SPN 818 Voltage Protection causing FMI 16 to set. Possible FMIs - SPN 818 Circuit Description The possible FMIs for SPN 818 are as follows: The ECM uses a 5 volt reference system for various sensor reference voltages.

  • Page 49: Spn 818, Fmi 4: Short 5V Supply Low

    SPN 818, FMI 4: Short 5V Supply Low Step Action 1. Turn Ignition OFF. No current issue. Go to step 2. 2. Back probe terminal 5 (Red/White wire) at the operator panel connector. 3. Connect terminal 5 back probe to red meter test lead on DVOM. 4.

  • Page 50: Spn 1110 Engine Over Temperature For Maximum Allowed Time

    The engine temperature monitoring function needs to SPN 1110 Engine Over Temperature For be thought of as a two-step system: Maximum Allowed Time Engine begins to overheat, SPN 1569 and SPN 6805 are triggered and engine torque is reduced by limiting the Circuit Description throttle and engine speed.

  • Page 51: Spn 1268 Cylinder 1 Ignition Coil

    SPN 1268 Cylinder 1 Ignition Coil Circuit Description Possible FMIs - SPN 1268 The ignition coil has an ignition (B+ voltage) and a ground The possible FMIs for SPN 1268 are as follows: circuit. The ECM controls the ignition coil by completing the Description ground circuit as needed.

  • Page 52: Spn 1268, Fmi 3: Short To High/Open

    SPN 1268, FMI 3: Short to High/Open Step Action 1. Perform the Ignition Coil Spark Test. See TEST PROCEDURES in this section. Problem does not Go to step 2. currently exist. 2. Did the test Pass? 1. Turn Ignition OFF. No current problem.

  • Page 53: Spn 1268, Fmi 4: Short Low

    SPN 1268, FMI 4: Short Low Step Action 1. Perform the Ignition Coil Spark Test. See TEST PROCEDURES in this Problem does not currently exist. Go to step 2. section. 2. Did the test Pass? 1. Turn Ignition OFF. No problem. Go to step 3.

  • Page 54: Spn 1569 Engine Over Temperature While Running

    The engine temperature monitoring function needs to SPN 1569 Engine Over Temperature While be thought of as a two-step system: Running Engine begins to overheat, SPN 1569 and SPN 6805 are triggered and engine torque is reduced by limiting the Circuit Description throttle and engine speed.

  • Page 55: Spn 5419 Electronic Throttle Control (Etc)

    SPN 5419 Electronic Throttle Control (ETC) Circuit Description Possible FMIs - SPN 5419 The ETC controls engine speed with a DC motor built into The possible FMIs for SPN 5419 are as follows: the throttle body. The DC motor movement is very precise Description and computer controlled from the feedback from the TPS and ETC Driver Pin 1 and/or Pin 2 Shorted High...

  • Page 56: Spn 6805 Diagnostic

    The engine temperature monitoring function needs to SPN 6805 Diagnostic be thought of as a two-step system: Engine begins to overheat, SPN 1569 and SPN 6805 are Circuit Description triggered and engine torque is reduced by limiting the The ECM monitors the EHT for high engine temperature. throttle and engine speed.

  • Page 57: Spn 7753 Starter Motor Input Signal

    SPN 7753 Starter Motor Input Signal high (FMI 3). The ECM then disables the output voltage Circuit Description commanded to the starter motor solenoid. The ECM monitors the starter input command signal from the key switch to the ECM. When the key switch is in the START Possible FMIs - SPN 7753 position, start voltage is sent from the key switch to the ECM.

  • Page 58: Spn 7753, Fmi 3: Input Signal Shorted High

    SPN 7753, FMI 3: Input Signal Shorted High Step Action 1. Turn ignition OFF. Proceed to Step 2. Make sure the battery is 2. Back probe terminal 1 (Yellow/Red wire) of the key switch electrical connector. connected and fully charged. 3.
  • Page 59 SECTION 4 - WIRE HARNESS SCHEMATICS AND PIN-OUTS ECM CONNECTOR PIN-OUT ---------------------------------------------------------------------------------------------------------------------------61 25E300 WIRING HARNESS DIAGRAM -------------------------------------------------------------------------------------------------------------- 62 vanguardpower.com...
  • Page 60 ECM Connector Pin-Out Connector Pin Number Wire Color Function Green CAN LO Yellow CAN HI Violet/Black Ignition Coil Black/Red Tachometer Output Orange/Black Yellow/Red Start Signal White/Red Manifold Air Pressure Brown Sensor Ground Red/White 5V Sensor Power Cylinder Head Temperature Sensor Green Oil Level Sensor Tan/Black...
  • Page 61 25E300 Wiring Harness Diagram vanguardpower.com...
  • Page 63 SECTION 5 - SYMPTOMS AND TROUBLESHOOTING GUIDE INTRODUCTION -------------------------------------------------------------------------------------------------------------------------------------------- 65 PRELIMINARY INSTRUCTIONS ----------------------------------------------------------------------------------------------------------------------- 65 ENGINE DOES NOT CRANK --------------------------------------------------------------------------------------------------------------------------- 66 ENGINE CRANKS BUT DOES NOT START ------------------------------------------------------------------------------------------------------- 67 ENGINE IS HARD TO START -------------------------------------------------------------------------------------------------------------------------- 68 ENGINE POWER OUTPUT LOW ---------------------------------------------------------------------------------------------------------------------- 69 ENGINE HUNTS AND SURGES ----------------------------------------------------------------------------------------------------------------------- 71 vanguardpower.com...

  • Page 64: Introduction

    • Inspect the spark plug condition and service if Introduction necessary. See SECTION 6 - REMOVAL AND INSTALLATION - Spark Plug. Verify Customer Complaint • Inspect the fuel filter condition and service if necessary. Verify customer complaint and then move to the Diagnostic See SECTION 6 - REMOVAL AND INSTALLATION - Table that best describes the problem.

  • Page 65: Engine Does Not Crank

    Engine Does Not Crank Step Action Perform OBD System Check. Go to applicable DTC Table. Go to step 2. Are any DTCs found? Perform a careful visual check. Repair Go to step 3. Is a problem found? Check battery as follows: Repair Go to step 4.

  • Page 66: Engine Cranks But Does Not Start

    Engine Cranks But Does Not Start Step Action Perform OBD System Check. Go to applicable DTC Table. Go to step 2. Are any DTCs found? Perform a careful visual check. Repair Go to step 3. Is a problem found? Verify fuel in tank(s). Go to step 4.

  • Page 67: Engine Is Hard To Start

    Engine Is Hard To Start Definition: Engine cranks OK, but does not start for a long time. Engine does run, or may start but immediately die. Step Action Perform OBD System Check. Go to applicable DTC Table. Go to step 2. Are any DTCs found? Perform a careful visual check.

  • Page 68: Engine Power Output Low

    Engine Power Output Low Step Action Perform OBD System Check. Go to applicable DTC Table. Go to step 2. Are any DTCs found? Perform a careful visual check. Repair Go to step 3. Is a problem found? Check the following fuel system components for dirt, water, or other Repair Go to step 4.
  • Page 69 Review diagnostic procedures in this table. If all steps have been Repair Contact engine completed and no problems have been found, proceed as follows: manufacturer. • Repeat visual check. • Review Diagnostic Tool/Code Reader data. • Check all electrical connections within the suspect circuit and/ or system.

  • Page 70: Engine Hunts And Surges

    Engine Hunts and Surges Step Action Perform OBD System Check. Go to applicable DTC Table. Go to step 2. Are any DTCs found? Perform a careful visual check. Repair Go to step 3. Is a problem found? Check the following fuel system components for dirt, water, or other Repair Go to step 4.
  • Page 71 Fuel Vent Hose - Removal ------------------------------------------------------------------------------------------------------------------------- 86 Fuel Vent Hose - Installation ----------------------------------------------------------------------------------------------------------------------- 87 Model 25E300 Fuel Hose Location and Routing - With Tank ----------------------------------------------------------------------------- 88 Model 25E300 Fuel Hose Location and Routing - Tankless ------------------------------------------------------------------------------- 89 MECHANICAL FUEL PUMP ----------------------------------------------------------------------------------------------------------------------------- 90...
  • Page 72 Mechanical Fuel Pump - Removal ----------------------------------------------------------------------------------------------------------------90 Mechanical Fuel Pump - Installation ------------------------------------------------------------------------------------------------------------- 90 FUEL FILTER ------------------------------------------------------------------------------------------------------------------------------------------------ 90 Fuel Filter - Removal --------------------------------------------------------------------------------------------------------------------------------- 90 Fuel Filter - Installation -------------------------------------------------------------------------------------------------------------------------------91 FUEL INJECTOR ------------------------------------------------------------------------------------------------------------------------------------------- 91 Fuel Injector - Removal ------------------------------------------------------------------------------------------------------------------------------ 91 Fuel Injector - Installation --------------------------------------------------------------------------------------------------------------------------- 92 Update Fuel Injector Calibration -------------------------------------------------------------------------------------------------------------------93 ELECTRONIC THROTTLE CONTROL (ETC) ------------------------------------------------------------------------------------------------------ 94 Electronic Throttle Control (ETC) - Removal ---------------------------------------------------------------------------------------------------94...

  • Page 73: Preliminary Instructions

    If equipped with an operator's panel, remove the two Preliminary Instructions fasteners (A, Figure 11) that secure the front panel to the operator's panel. Prior to starting any diagnostic, repair or maintenance operation. Make sure you are familiar with ALL safety warnings and procedures as outlined in SECTION 1 - SAFETY AND GENERAL INFORMATION - General Safety Messages.

  • Page 74: Air Cleaner Assembly

    Remove the valve cover breather hose from the air Air Cleaner Assembly cleaner base port (A, Figure 13). Depending on your engine's trim, the air cleaner assembly may be high-mount, low-mount or remote. If equipped with the high-mount air cleaner, proceed to Air Cleaner Assembly - High Mount - Removal and Installation.

  • Page 75: Air Cleaner Assembly - High Mount - Installation

    Remove the valve cover breather hose from the air Air Cleaner Assembly - High Mount - Installation cleaner base port (A, Figure 15). Prior to assembly and installation, make sure that all mating and gasket surfaces are clean, dry and free from contamination.

  • Page 76: Air Cleaner Assembly - Low Mount - Installation

    Remove the rear air cleaner mounting fastener (A, Figure Start by hand the lower support bracket fastener (A, 17). Figure 16). Tighten to 95 lb-in (10.7 Nm). Start by hand the rear air cleaner mounting fastener (A, Figure 17). Tighten to 50 lb-in (5.6 Nm). Install the valve cover breather hose onto the air cleaner port (A, Figure 15).

  • Page 77: Rewind Starter

    Remove electronic throttle control (ETC), see Electronic Rewind Starter Throttle Control (ETC) - Removal. Depending on your engine's trim, the rewind handle position Remove rewind starter, see Rewind Starter - Removal. may be located at the 8, 10, 12 or 2 O'clock position. Prior Remove the five blower housing to engine block to disassembly, note the position on your engine.

  • Page 78: Side Cover

    Remove the upper operator panel to side cover fastener Side Cover (A, Figure 23). Side Cover - Removal Remove the connector cover from the side cover. Lift the tab of the snap latch (A, Figure 21) and rotate the cover away from the engine to remove. Remove the two side cover to mounting bracket fasteners (C-D, Figure 22).

  • Page 79: Operator Panel

    Disconnect the key switch electrical connector from the Operator Panel rear of the operator panel (A, Figure 25). Operator Panel - Removal Remove the four operator panel fasteners (A-D, Figure 24). If equipped, disconnect the speed control electrical Pull the operator panel away from the engine to access connector from the rear of the operator panel (B).

  • Page 80: Fuel Tank

    At the rear of the engine (PTO side), remove the rear fuel Fuel Tank tank fastener (A, Figure 27). Depending on your engine's trim, the fuel tank may be remotely mounted on the equipment. Consult your equipment repair manual for proper procedures. If your engine is equipped with a fuel tank mounted atop the engine, proceed as follows.

  • Page 81: Fuel Tank - Installation

    Disconnect the fuel return hose (A, Figure 29) at the fuel Squeeze the tangs on the fuel hose clamp and slide the tank. Squeeze the tangs of the fuel line clamp and slide clamp along the hose until it is positioned above the tank the clamp along the fuel hose away from the tank.

  • Page 82: Fuel Hoses

    Disconnect the fuel supply hose from the fuel pump (A, Fuel Hoses Figure 31). Squeeze the tangs of the hose clamp and slide the clamp along the hose away from the pump. Using the fuel line removal tool, remove the fuel line from Fuel Supply Hoses - Removal the fuel pump port.

  • Page 83: Fuel Supply Hoses - Installation

    Disconnect the fuel supply hose from the bottom fuel Squeeze the tangs of the fuel hose clamp and slide hose filter port (D, Figure 31). Squeeze the tangs of the hose clamp over the injector port until it is 1/8 inch (3 mm) clamp and slide the clamp along the hose away from the from end of hose.

  • Page 84: Fuel Return Hose - Removal

    Feed the fuel hose underneath the wire harness to Fuel Return Hose - Removal remove from engine. The fuel return hose takes unused fuel from the fuel injector and returns it to the fuel tank for reuse. On engines equipped  NOTE: On some engines with a remote fuel tank, the fuel with an engine mounted fuel tank, the fuel return line return hose can be routed underneath the cylinder head air connects between the fuel injector return port and the...

  • Page 85: Fuel Pump Pulse Hose - Removal

    Fuel Pump Pulse Hose - Removal Fuel Pump Pulse Hose - Installation The fuel pump pulse hose runs between the crankcase port. Feed the pulse hose underneath the fuel pump bracket and the fuel tank from the fuel pump side of the engine. Remove engine side cover.

  • Page 86: Fuel Vent Hose - Installation

    Continue feeding the vent line out from the engine until Press the vent hose onto the ETC port until the end of free. the hose contacts the port flange (A, Figure 36). Connect the vent hose to the remote fuel tank. See equipment repair manual for proper procedure.

  • Page 87: Model 25E300 Fuel Hose Location And Routing - With Tank

    Model 25E300 Fuel Hose Location and Routing - With Tank vanguardpower.com...

  • Page 88: Model 25E300 Fuel Hose Location And Routing - Tankless

    Model 25E300 Fuel Hose Location and Routing - Tankless...

  • Page 89: Mechanical Fuel Pump

    Remove the fuel inlet, fuel outlet and pulse hose from the Mechanical Fuel Pump fuel pump. Depending on your engine's trim, a Mikuni or Nikki fuel pump  NOTE: Some residual fuel may be present in the fuel lines may be installed. The Mikuni fuel pump is characterized by and pump.

  • Page 90: Fuel Filter - Installation

    Using a fuel line removal tool, remove fuel inlet and outlet Squeeze the clamp tangs (A, Figure 39) and move each hoses from fuel filter fittings. hose clamp until positioned above the fuel filter port and 1/8 inch (3 mm) from end of each hose.  NOTE: Depending on your engine's trim, a remote fuel tank may be equipped.

  • Page 91: Fuel Injector - Installation

    Using a pliers, squeeze the fuel line clamp tabs (D) Install fuel injector O-ring, if not already installed (A, together and slide the clamps along the fuel line to allow Figure 43). for removal of the fuel lines. Repeat this step for both the supply and return fuel line.

  • Page 92: Update Fuel Injector Calibration

    Remove the two fuel line clamps from the fuel feed and Click "Ok" (E) in the prompt box. return lines.  NOTE: If replacing the fuel injector with new, you MUST update the fuel injector calibration. Proceed to Update Fuel Injector Calibration in this section. Update Fuel Injector Calibration See SECTION 2 - DIAGNOSTIC INTRODUCTION - Using the Diagnostic Tool and Software.

  • Page 93: Electronic Throttle Control (Etc)

    After the fuel injector data has been successfully flashed, Disconnect the ETC electrical connector from the bottom a prompt will appear (G, Figure 47). Click "OK." of the throttle body housing (A, Figure 48). If the fuel injector data did NOT successfully update, repeat steps 2 through 7.

  • Page 94: Tmap Sensor - Removal

    Sub-assemble the throttle body as follows: Insert the two throttle body mounting studs through the throttle assembly bores. From the air cleaner side of the throttle body, the SHORT stud mounts in the LEFT bore and the LONG stud mounts in the RIGHT bore.

  • Page 95: Ignition Coil

    Remove the ignition coil (D) from the spark plug by Ignition Coil pulling the ignition coil and boot up and away from the spark plug. Set aside. Ignition Coil - Removal Ignition Coil - Installation Disconnect the ignition coil electrical connector (A, Install the ignition coil (D, Figure 51) onto the spark plug Figure 51) by first pulling up on the locking tab and by pressing firmly until the boot is seated.

  • Page 96: Crankshaft Position Sensor (Ckp)

    Using a 5/8 inch spark plug socket, tighten to 170 lb-in Start by hand the two crankshaft position sensor (19.2 Nm). fasteners. Tighten until the fastener head makes contact with the sensor. DO NOT overtighten as the sensor air gap needs to be adjusted prior to final torqueing. Crankshaft Position Sensor (CKP) Using a feeler gauge, adjust the sensor air gap to 0.010-0.015 in (0.25-0.38 mm).

  • Page 97: Wire Harness

    11. Remove the fastener securing the battery ground ring Wire Harness terminal to the side cover lower mounting bracket (A, Figure 58). Remove ground ring terminal from fastener. Wire Harness - Removal Starting on the starter motor side of the engine, remove the starter motor solenoid terminal nut, washer and lock washer (A, Figure 57).

  • Page 98: Wire Harness - Installation

    20. Remove the fir tree style cable clip (D) from the cylinder Wire Harness - Installation head air guide. 21. Disconnect the fuel injector electrical connector (E) by Starting at the cylinder head side of the engine, install the pulling out the red lock tab and then depressing the EHT sensor and fastener.

  • Page 99: Engine Control Module (Ecm)

    22. Connect the oil level sensor harness terminal to the Disconnect the ECM harness connector by depressing sensor terminal. Press both terminal together until fully the tab and then pivoting the latch down (A, Figure 62) to seated. release the connector. 23.
  • Page 100 Install the fir tree style harness clip (A) into the ECM  NOTE: If replacing the ECM with new, you MUST connect shield hole by pressing the clip into place until the flange to the diagnostic tool software and update the ECM and fuel is flush with the shield.
  • Page 101 SECTION 7 - SPECIFICATIONS ENGINE SPECIFICATIONS ---------------------------------------------------------------------------------------------------------------------------- 103 TORQUE SPECIFICATIONS ---------------------------------------------------------------------------------------------------------------------------104 vanguardpower.com...
  • Page 102 Engine Specifications ENGINE - 25E300 Bore 3.465 in (88 mm) Stroke 2.638 in (67 mm) Displacement 24.898 ci (408 cc) Compression Ratio 8.4:1 Crankshaft End Play 0.010-0.019 in (0.25-0.48 mm) Crankshaft End Play (Pump Applications) 0.005-0.120 in (0.12-0.3 mm) Oil Capacity...
  • Page 103 Torque Specifications Fastener Torque Air Cleaner to Throttle Body 40 lb-in (4.5 Nm) Air Cleaner Upper Fastener/Ignition Coil Heat Shield 95 lb-in (10.7 Nm) Air Cleaner Lower Support Bracket to Engine Block - Low Mount 95 lb-in (10.7 Nm) Air Cleaner Lower Rear Support - Low-Mount 50 lb-in (5.6 Nm) Blower Housing to Engine Block 96 lb-in (10.7 Nm)
  • Page 104 BRIGGS & STRATTON CUSTOMER EDUCATION Milwaukee, WI 53201 USA Copyright ©2023. All rights reserved. VANGUARDPOWER.COM 80126188 Rev A...

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