Page 94
TROUBLESHOOTING
EXCESSIVE BLUE OR WHITE SMOKE
EXHAUST GAS SEEPING INTO CAB
EXCESSIVE FUEL CONSUMPTION
Possible Cause Correction
1. Code(s) present. 1. Correct cause of code(s).
2. No code(s) present, faulty cylinder. 2. Isolate faulty cylinder and repair as required.
3. EGR cooler leaking coolant into air/EGR inlet
tubes.
3. Pressure-test coolant side of EGR cooler by submersion using low
air pressure. Replace any coolers which produce bubbles through
EGR passages.
4. Low fuel pressure. 4. Check fuel lines and filters for blockage.
5. Engine lubricating oil level too high. 5. Drain excess lubricating oil. If the oil is contaminated with either fuel
or coolant, completely drain the oil pan. Change the oil filters.
Locate the source of the leak and correct. Fill with MACK-specified
engine oil. Check the oil level with the dipstick. DO NOT overfill.
6. Turbocharger passing oil. 6. Check for oil in the inlet manifold. Check for air inlet restriction
(clogged air filter). Repair or replace turbocharger as required.
7. Worn piston rings. 7. Determine and correct the root cause, and repair engine as
required.
8. Engine misfiring or running rough. 8. Check items as outlined in ENGINE MISFIRES — NO CODE(S)
chart.
Possible Cause Correction
1. Cracked EGR valve housing. 1. Replace EGR valve.
2. Cracked EGR valve-to-cooler pipe including
expansion joint (bellows).
2. Inspect EGR valve-to-cooler pipe and correct or replace leaking
component(s).
3. Exhaust leak at EGR poppet valve. 3. Exhaust leak past EGR valve poppet stem and support bushing.
Replace EGR valve.
4. Exhaust leak at turbocharger inlet or exhaust
pipe.
4. Inspect, locate and repair exhaust leak.
Possible Cause Correction
1. Code(s) present. 1. Correct cause of code(s).
2. Restrictions in the air induction system. 2. Inspect system. Remove restrictions and replace defective parts as
required.
3. External fuel system leakage. 3. Check external piping on fuel system for signs of fuel leakage.
Repair as required.
4. Defective injection nozzle assembly. 4. Isolate defective nozzle assembly. Repair and replace as required.
Refer to item 8 in ENGINE MISFIRES — NO CODE(S) chart.
5. Internal engine wear. 5. Determine and correct the root cause, and repair engine as
required.
6. Air conditioning system commanding the engine
cooling fan to be operating at all times.
6. If the engine fan is operating constantly, change the EECU
customer data to indicate that no A/C is installed. Check the
operation of the fan. If the fan disengages, restore the original
settings in the EECU and repair the A/C system.
5-111.bk Page 94 Monday, July 10, 2006 2:26 PM
To Next Page
Loading...
