GMC 4000 Series Service Manual page 316

POSSIBLE CAUSES
3. Injection pump not properly timed to engine.
4. Incorrect engine valve timing.
5. Injection nozzles leaking (worn), or improper
opening pressure.
6. Wrong grade or type of fuel.
7. Engine overheating.
8. Poor cylinder com pression.
9. Damaged or worn pistons, and/or piston rings.
10. Cylinder overfueled.
SYMPTOM B - EXCESSIVE WHITE OR BLUE SMOKE
POSSIBLE CAUSES
1. Oil level in air cleaner too high.
2. Injection pump not properly timed to engine.
3. Engine crankcase oil level too high.
4. Engine running too cool.
5. Poor cylinder com pression.
6. Damaged or worn pistons and/or piston rings.
7. Wrong grade or type of fuel.
POSSIBLE CAUSES
1. Oil lines or connections leaking.
2. Leaking gaskets.
3. Crankcase oil level too high.
4. Pistons and/or rings worn, or pistons damaged.
(When checked with engine at normal operating temperature)
POSSIBLE CAUSES
1. Defective oil gauge or sending unit.
2. Oil viscosity too low.
3. Oil diluted with fuel oil.
4. Suction lo ss.
5. Weak or broken relief valve spring in oil pump.
G M C S E R V I C E M A N U A L ______________
EXHAUST ANALYSIS (CONT'D)
HIGH LUBRICATING OIL CONSUM PTION
LOW ENGINE OIL PRESSURE
TORO-FLOW DIESEL ENGINE
REMEDY
3. Correct injection timing.
4. Check and correct as necessary.
5. Remove nozzle assem blies, test, replace or r e ­
pair as necessary.
6. Fill tank with correct fuel. (Refer to current
GMC D iesel Fuel Oil Bulletin.)
7. Correct cooling system malfunction.
8. Check and correct as required.
9. Overhaul engine.
10. Have injection pump recalibrated. Check for
excess fuel device sticking.
REMEDY
1. Service air cleaner.
2. Retime correctly.
3. Drain crankcase and refill to correct level.
4. Correct cooling system malfunction.
5. Check and correct as required.
6. Overhaul engine.
7. Fill tank with correct fuel. (Refer to current
GMC D iesel Fuel Oil Bulletin.)
REMEDY
l. Tighten or replace defective parts.
2. Replace gaskets as necessary.
3. Drain crankcase and refill to correct level.
4. Overhaul engine.
REMEDY
1. Check pressure with master gauge. Replace
oil gauge or sending unit if defective.
2. F ill crankcase with correct oil.
3. Check for indications of fuel oil entering crank­
case and make necessary correction.
4. Check for loose intake pipe and screen in oil
pan. Also checkf or partially clogged inlet screen.
5. Inspect spring and replace if necessary.
Sec. 6B
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