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200 TROUBLESHOOTING
Page 9-3
ENGINE MISFIRES
200768a
ENGINE STALLS AT LOW SPEEDS
200769a
Possible Cause
Correction
1. Poor quality fuel, or water or dirt in the
fuel.
1. Drain fuel from tanks. Replace fuel filters and fill tank with MACK-
specified diesel fuel.
2. Air in fuel system.
2. Check fuel system for air leaks. Repair as necessary. (Air generally
gets into the fuel system on the suction side of the fuel pump.)
3. Broken or leaking high-pressure fuel
lines.
3. Check for fuel leaks. Repair as necessary.
4. Restricted fuel lines or drain lines.
4. Check for proper fuel flow. If no flow, replace lines.
5. Low fuel-supply pressure.
5. Check to be sure there is fuel in the fuel tank. Check for sharp bends or
kinks in the fuel line between the fuel tank and the fuel transfer pump.
Also check for clogged suction pipe (in the fuel tank) or a plugged fuel
suction hose. Check for air in the fuel system, and check the fuel
pressure. If the pressure is lower than specified, replace the fuel filters.
If still low, replace the transfer pump.
6. Improper valve lash adjustment.
6. Check adjustment. Correct as necessary.
7. Defective fuel injection nozzles or fuel
pump.
7. Run engine at speed which gives maximum misfiring or rough running.
Cut the fuel flow to each cylinder, one at a time, by loosening the fuel
line nut on the injection pump. If engine rpm does not change when the
fuel is cut to a cylinder, it indicates that the cylinder is not firing. Remove
the injection nozzle and check. Repair or replace as necessary. If nozzle
is OK, check cylinder for low compression. If no fuel is present when line
is loosened, pump may be defective. Repair or replace as required.
8. Improper timing.
8. Check fuel injection pump to engine timing.
9. Cylinder head gasket leakage.
9. Check for visible signs of leakage, coolant in the oil, or traces of oil in
the coolant. Use a compression tester to check each cylinder. Replace
cylinder head gasket if necessary.
10. Worn camshaft lobe.
10. With valve lash properly adjusted, check rocker arm movement. If not
within specifications, replace worn parts.
Possible Cause
Correction
1. Idle speed set too low.
1. Check idle setting. Adjust as necessary.
2. Fuel tank vent clogged or partially clogged.
2. Check fuel tank vents. Repair as necessary.
3. Low fuel supply.
3. Check for sufficient fuel in the fuel tank. Check for fuel leaks. Check
for kinks or sharp bends in the fuel lines. Check fuel pressure; it
must be within specifications. If not, replace fuel filters. If still low,
repair or replace transfer pump.
4. Injection pump overflow valve leaking, or stuck
open or closed.
4. Repair or replace valve.
5. Defective fuel injection nozzle.
5. Isolate defective nozzle and replace. Refer to item 7 in preceding
ENGINE MISFIRES section.
6. Defective fuel injection pump.
6. Remove, repair, and reinstall pump.
7. High parasitic load.
7. Check for excessive loading due to engaged auxiliary attachments.
5-101.bk Page 3 Friday, March 17, 2006 11:05 AM
Summary of Contents for E7
Page 1: ...E7 ENGINE OVERHAUL AUGUST 1997 ENGINE 5 101...
Page 2: ...Page 0 front fr5 Page 0 Friday March 17 2006 11 04 AM...
Page 5: ...E7ENGINE OVERHAUL MARCH 2006 2 5M REP AUGUST 1997 10M MACK TRUCKS INC 1997 ENGINE 5 101...
Page 13: ...ABOUT THIS MANUAL Page ix ABOUT THIS MANUAL front fr5 Page ix Friday March 17 2006 11 04 AM...
Page 15: ...TABLE OF CONTENTS Page xi TABLE OF CONTENTS front fr5 Page xi Friday March 17 2006 11 04 AM...
Page 24: ...Page xx NOTES front fr5 Page xx Friday March 17 2006 11 04 AM...
Page 31: ...200 SPECIFICATIONS Page 2 1 SPECIFICATIONS 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 55: ...200 ENGINE REMOVAL Page 3 1 ENGINE REMOVAL 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 58: ...Page 3 4 NOTES 5 101 bk Page 4 Friday March 17 2006 11 05 AM...
Page 90: ...Page 4 32 NOTES 5 101 bk Page 32 Friday March 17 2006 11 05 AM...
Page 91: ...200 BENCH PROCEDURES Page 5 1 BENCH PROCEDURES 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 158: ...Page 5 68 NOTES 5 101 bk Page 68 Friday March 17 2006 11 05 AM...
Page 159: ...200 ENGINE ASSEMBLY Page 6 1 ENGINE ASSEMBLY 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 240: ...Page 6 82 NOTES 5 101 bk Page 82 Friday March 17 2006 11 05 AM...
Page 272: ...Page 8 10 NOTES 5 101 bk Page 10 Friday March 17 2006 11 05 AM...
Page 273: ...200 TROUBLESHOOTING Page 9 1 TROUBLESHOOTING 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 292: ...Page 9 20 NOTES 5 101 bk Page 20 Friday March 17 2006 11 05 AM...
Page 293: ...200 APPENDIX Page 10 1 APPENDIX 5 101 bk Page 1 Friday March 17 2006 11 05 AM...
Page 295: ...200 APPENDIX Page 10 3 E7 LUBRICATION SYSTEM 5 101 bk Page 3 Friday March 17 2006 11 05 AM...
Page 296: ...Page 10 4 200 APPENDIX E7 COOLING SYSTEM 5 101 bk Page 4 Friday March 17 2006 11 05 AM...
Page 297: ...INDEX Page 11 1 INDEX INDEX FR5 Page 1 Friday March 17 2006 11 04 AM...
Page 302: ...Page 11 6 NOTES INDEX FR5 Page 6 Friday March 17 2006 11 04 AM...
Page 303: ...E7 ENGINE OVERHAUL PRINTED IN U S A ENGINE 5 101 MACK TRUCKS INC 1997...