Gasoline Fuel Injection Trouble Shooting

CONDITION	POSSIBLE CAUSE	CORRECTION
COLD START SYMPTOM
Engine cranks, will not start	1) Fuel pump not working	1) Check fuel pump and double fuse relay, replace as necessary
	2) "Cold" control pressure incorrect (CIS)	2) Replace warm-up regulator if pressure not to specification
	3) Auxiliary air valve does not open	3) Replace valve
	4) Cold start valve does not operate	4) Check electrical power to valve, replace valve if necessary
	5) Cold start valve leaking	5) Replace valve
	6) Sensor plate stop set incorrectly (CIS)	6) Adjust to specifications
	7) Sensor plate and/or plunger sticking	7) Free up or replace as needed
	8) Vacuum leak	8) Repair vacuum leaks
	9) Fuel system leak	9) Repair fuel leaks
	10) Faulty Thermo Time switch	10) Replace switch
	11) Distributor triggering contacts (AFC & EFI)	11) Repair or replace as needed
	12) Temperature sensors 1 & 2 (AFC & EFI)	12) Replace as necessary
Engine hard starting	1) "Cold" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Auxiliary air valve does not open	2) Replace valve
	3) Cold start valve does not open	3) Check for electrical power to valve, replace valve if necessary
	4) Cold start valve leaking	4) Replace cold start valve
	5) Sensor plate stop set incorrectly (CIS)	5) Adjust sensor plate stop to specifications
	6) Sensor plate and/or plunger stuck (CIS)	6) Free up or replace as necessary
	7) Vacuum leak(s)	7) Repair vacuum leak(s)
	8) Fuel leak(s)	8) Repair fuel leak(s)
	9) Thermo Time switch does not close	9) Replace Thermo Time switch
HOT STARTING SYMPTOM
Engine cranks, will not start	1) Electric fuel pump not operating	1) Check fuel pump and relay fuse, replace as needed
	2) "Warm" control pressure incorrect (CIS)	2) Replace warm-up regulator
	3) Sensor plate stop adjustment incorrect (CIS)	3) Adjust sensor plate stop
	4) Sensor plate and/or plunger stuck (CIS)	4) Free up or replace
	5) Vacuum leak(s)	5) Repair vacuum leak(s)
	6) Fuel system leak(s)	6) Repair fuel leak(s)
	7) Injectors leaking	7) Clean or replace as necessary
	8) Idle mixture out of adjustment	8) Adjust mixture to specifications
Engine Hard Starting (Long Cranking Time)	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Auxiliary air valve does not close	2) Replace valve
	3) Sensor plate stop adjustment incorrect (CIS)	3) Adjust to specification
	4) Sensor plate and/or plunger stuck (CIS)	4) Free up or replace as necessary
	5) Vacuum leak(s)	5) Repair vacuum leak(s)
	6) Fuel system leaks	6) Repair fuel leak(s)
	7) Injectors leaking	7) Clean or replace as necessary
	8) Idle mixture out of adjustment	8) Adjust mixture to specifications
COLD ENGINE DRIVEABILITY SYMPTOM
Rough Idle During Warm-Up	1) "Cold" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Auxiliary air valve does not close	2) Replace valve
	3) Auxiliary air valve does not open	3) Replace valve
	4) Cold start valve leaking	4) Clean or replace valve
	5) Vacuum leak	5) Repair vacuum leaks
	6) Fuel system leak(s)	6) Repair fuel leaks
	7) Injectors leaking	7) Clean or replace as necessary
HOT ENGINE DRIVEABILITY SYMPTOM
Rough idle with warm engine	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Auxiliary air valve does not close	2) Replace air valve
	3) Faulty cold start valve	3) Clean or replace as necessary
	4) Sensor plate and/or plunger stuck (CIS)	4) Free up or replace as necessary
	5) Vacuum leak(s)	5) Repair vacuum leak(s)
	6) Fuel system leak(s)	6) Repair fuel leak(s)
	7) Injectors leaking	7) Clean or replace injectors
	8) Idle mixture out of adjustment	8) Adjust mixture to specifications
CO level too high at idle	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Cold start valve leaking	2) Replace valve
	3) Sensor plate and/or plunger stuck (CIS)	3) Free up or replace as necessary
	4) Fuel system leaking	4) Repair fuel leak(s)
	5) Idle mixture out of adjustment	5) Adjust mixture to specifications
CO level too low at idle	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Vacuum leak	2) Repair vacuum leak(s)
	3) Idle mixture out of adjustment	3) Adjust mixture to specifications
Poor engine performance	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Cold start valve leaking	2) Clean or replace valve
	3) Sensor plate and/or plunger stuck (CIS)	3) Free up or replace as necessary
	4) Idle mixture out of adjustment	4) Adjust mixture to specifications
	5) Throttle valve does not open completely	5) Check and adjust as necessary
Excessive fuel consumption	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Cold start valve leaks	2) Clean or replace as necessary
	3) Fuel system leaking	3) Repair fuel leak(s)
	4) Idle mixture out of adjustment	4) Adjust mixture to specifications
Engine misfire at high speed	1) Loose electrical contact at fuel pump	1) Check and repair as necessary
	2) Primary pressure too low or too high	2) Check pressure and adjust if not within specifications
	3) Fuel system leaking	3) Repair fuel leak(s)
Engine "Diesels"	1) Sensor plate and/or plunger stuck (CIS)	1) Free up or replace as necessary
	2) Injectors leaking	2) Clean or replace as necessary
	3) Faulty cold start valve	3) Clean or replace as necessary
Idle Speed Too High and Cannot Be Adjusted Lower	1) Auxiliary air valve does not close	1) Replace valve
Engine Backfires into Intake Manifold	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Vacuum leak(s)	2) Repair vacuum leaks
	3) Idle mixture out of adjustment	3) Adjust mixture to specifications
Engine Backfires into Exhaust Manifold	1) "Warm" control pressure incorrect (CIS)	1) Replace warm-up regulator
	2) Cold start valve leaks	2) Clean or replace as necessary
	3) Fuel system leaking	3) Repair fuel leaks
	4) Idle mixture out of adjustment	4) Adjust mixture to specifications