Chrysler 1991 Service Manual Supplement page 70

5.9L (DIESEL) ENGINES 9 - 7
SERVICE DIAGNOSIS - PERFORMANCE (CONT.)
POSSIBLE CAUSES C01RECTION
ENGINE HARD TO
START, OR WILL
NOT START—SMOKE
FROM EXHAUST
(Cont'd)
Fuel pump inoperative.
Injection pump throttle linkage
loose or damaged.
Contaminated fuel.
Worn or inoperative injection
pump.
Injection pump out of time.
Valves incorrectly adjusted.
One or more injectors worn or
not operating properly.
Disconnect fuel line and verify fuel delivery. If needed replace
pump.
Visually check the linkage. Tighten/replace linkage.
Verify by operating the engine with clean fuel from a
temporary tank. Check for presence of gasoline. Drain and
flush fuel supply tanks. Replace fuel/water separator filter.
Visually check fuel delivery with an externally connected
injector to one of the pump outlets. Replace the pump if fuel is
not being delivered.
Check/time the pump (refer to Group 14, Fuel System).
Adjust valves.
Check/replace bad improperly operating injectors.
ENGINE STARTS,
BUT WILL NOT
KEEP RUNNING
Idle speed too low for the,
accessories.
Intake air or exhaust system
restricted.
Air in the fuel system or the
fuel supply is inadequate.
Fuel waxing due to extremely
cold weather.
Contaminated fuel.
Adjust the idle speed.
Visually check for exhaust restriction and inspect the air intake.
Repair/replace restricting parts.
Check the flow through the filter and bleed the system. Locate
and eliminate the air source.
Verify by inspecting the fuel filter. Clean the system and use
climatized fuel. Replace fuel/water separator filter. Check fuel
heater for proper operation.
Verify by operating the engine with clean fuel from a temporary
supply tank. Check for presence of gasoline. Replace fuel/water
separator filter.
SURGING (SPEED
CHANGE)
If the condition occurs at idle,
the idle speed is set too low for
the accessories.
High pressure fuel leak.
One or more injectors worn or
not operating properly.
Improperly operating injection
pump.
Adjust the idle.
Inspect/correct leaks in the high pressure lines. Fittings and
delivery valve sealing washers.
Check/replace the inoperative injectors.
Replace the injection pump.
ROUGH IDLE
(IRREGULARLY FIRING
OR ENGINE SHAKING)
Cold engine.
Idle speed too low for the
accessories.
Engine mounts damaged or
loose.
Refer to troubleshooting logic for intake manifold heater system
(see Group 11, Exhaust System & Intake Manifold)
Adjust idle speed.
Repair or replace mounts.
J9109-233