Diesel Fuel Injection Trouble Shooting

CONDITION	POSSIBLE CAUSE	CORRECTION
Engine Won't Start	No voltage to fuel solenoid	Check electrical connections
	Faulty glow plugs or glow plug controls	Check and/or replace glow plugs or controller
	Plugged fuel return system	Remove restrictions
	No fuel to nozzles	Inspect fuel delivery system
	No fuel to injecton pump	Inspect fuel delivery system
	Clogged fuel tank filter	Replace filter, see FUEL
	Incorrect or contaminated fuel	Remove and replace fuel
	Incorrect pump timing	Reset pump timing, see FUEL
Engine Stalls at Idle	Incorrect slow idle adjustment	Reset idle adjustment, see TUNE-UP
	Faulty fast idle solenoid	Replace solenoid, see FUEL
	Plugged fuel return system	Remove restrictions
	Glow plugs turn off too soon	Check glow plug system, see FUEL
	Incorrect pump timing	Check and reset timing, see FUEL
	Limited fuel to injection pump	Check fuel delivery system
	Air in injection lines to nozzles	Check line fittings
	Incorrect or contaminated fuel	Remove and replace fuel
	Faulty injection pump	Remove and replace pump, see FUEL
	Fuel solenoid closes in RUN position	Check solenoid operation, see FUEL
Engine Starts, Idles Rough WITHOUT Unusual Noise or Smoke	Incorrect slow idle adjustment	Reset slow idle adjustment, see TUNE-UP
	Leaking injection line	Check fittings and/or replace line
	Plugged fuel return line	Remove restrictions
	Air in lines to nozzles	Check line fittings
	Air in injection pump	Check pump fittings and pump operation
	Faulty nozzle	Replace nozzle, see FUEL
	Improper or contaminated fuel	Remove and replace fuel
	Uneven fuel distribution	Check fuel delivery system
Engine Starts and Idles WITH Excessive Noise and/or Smoke	Incorrect pump timing	Reset injection pump timing, see FUEL
	Air in injection lines to nozzles	Check fittings on lines
	Faulty nozzle	Replace nozzle, see FUEL
	Improperly installed high pressure lines	Remove and reinstall properly
Engine Idles Okay but Misfires Above Idle	Plugged fuel filter	Remove restrictions and/or replace filter
	Incorrect pump timing	Reset injection pump timing, see FUEL
	Incorrect or contaminated fuel	Remove and replace fuel
Engine Will Not Idle	Linkage binding or misadjusted	Remove binding and readjust linkage
	Defective injection pump	Replace injection pump, see FUEL
Fuel Leaks With No Other Engine Malfunction	Loose or broken fuel line or connection	Check all fuel line fittings and correct
	Internal seal leak in injection pump	Remove and replace injection pump
Low Engine Power	Restricted air intake	Remove restrictions
	Plugged fuel filter	Remove restriction and/or replace filter
	Restricted fuel return system	Remove restrictions
	Restricted tank-to-pump fuel supply	Check fuel delivery system
	Incorrect or contaminated fuel	Remove and replace fuel
	Restricted fuel tank filter	Replace filter
	Nozzle or glow plug compression leaks	Check fittings and replace as required
	Plugged nozzle	Remove restriction and/or replace nozzle
"Rapping" Noise From One or More Cylinders	Air in fuel system	Check fuel delivery system for leaks
	Air in high pressure lines	Check fittings for leaks
	Nozzle sticking in open position	Inspect nozzle and/or replace
	Low nozzle opening pressure	Check nozzle operation, see FUEL
	Filter in nozzle broken or loose	Remove and replace filter, see FUEL
Excessive Combustion Noise With Black Smoke	Incorrect pump timing	Reset injection pump timing, see FUEL
	Incorrect pump housing pressure	Check pump for internal leaks, FUEL
	Defective injection pump	Replace injection pump, see FUEL
Engine Will Not Shut Off With Key	Injection pump fuel solenoid does not return to off position	Check solenoid operation, see FUEL

NOTE: For GASOLINE FUEL INJECTION TROUBLE SHOOTING, see the appropriate article under the individual manufacturer in this section. Also see the appropriate article in COMPUTERIZED ENGINE CONTROLS Section.