94 850: injectors don't pulse after warm up
1994 850
180,000 miles
non turbo / 2.4 liter CA emissions
It starts and runs normally when cold. It will not start after it has been running for at least 15 minutes and then shut off. If the engine is warm, the injectors do not pulse (I hooked up a noid light on an injector connector to discover this). After it cools down for a half hour or so, the injectors pulse during cranking, and it starts. Any ideas? I'm thinking maybe the wiring to the injector relay (above radiator) has too much resistance when hot... I'll check this tomorrow. Any ideas would be appreciated, Thanks!
Fuel Pressure normal (43 psi)
Crank / cam sensor OK
Fuel relays (by fuse panel and above radiator) OK
Spark at plugs
Compression Good
FUEL INJECTORS NOT PULSING DURING CRANKING WHEN ENGINE IS HOT ARGGHH!
180,000 miles
non turbo / 2.4 liter CA emissions
It starts and runs normally when cold. It will not start after it has been running for at least 15 minutes and then shut off. If the engine is warm, the injectors do not pulse (I hooked up a noid light on an injector connector to discover this). After it cools down for a half hour or so, the injectors pulse during cranking, and it starts. Any ideas? I'm thinking maybe the wiring to the injector relay (above radiator) has too much resistance when hot... I'll check this tomorrow. Any ideas would be appreciated, Thanks!
Fuel Pressure normal (43 psi)
Crank / cam sensor OK
Fuel relays (by fuse panel and above radiator) OK
Spark at plugs
Compression Good
FUEL INJECTORS NOT PULSING DURING CRANKING WHEN ENGINE IS HOT ARGGHH!
Last edited by saabvolvotech; Jan 1, 2014 at 02:35 PM.
1994 850
180,000 miles
non turbo / 2.4 liter CA emissions
It starts and runs normally when cold. It will not start after it has been running for at least 15 minutes and then shut off. If the engine is warm, the injectors do not pulse (I hooked up a noid light on an injector connector to discover this). After it cools down for a half hour or so, the injectors pulse during cranking, and it starts. Any ideas? I'm thinking maybe the wiring to the injector relay (above radiator) has too much resistance when hot... I'll check this tomorrow. Any ideas would be appreciated, Thanks!
Fuel Pressure normal (43 psi)
Crank / cam sensor OK
Fuel relays (by fuse panel and above radiator) OK
Spark at plugs
Compression Good
FUEL INJECTORS NOT PULSING DURING CRANKING WHEN ENGINE IS HOT ARGGHH!
180,000 miles
non turbo / 2.4 liter CA emissions
It starts and runs normally when cold. It will not start after it has been running for at least 15 minutes and then shut off. If the engine is warm, the injectors do not pulse (I hooked up a noid light on an injector connector to discover this). After it cools down for a half hour or so, the injectors pulse during cranking, and it starts. Any ideas? I'm thinking maybe the wiring to the injector relay (above radiator) has too much resistance when hot... I'll check this tomorrow. Any ideas would be appreciated, Thanks!
Fuel Pressure normal (43 psi)
Crank / cam sensor OK
Fuel relays (by fuse panel and above radiator) OK
Spark at plugs
Compression Good
FUEL INJECTORS NOT PULSING DURING CRANKING WHEN ENGINE IS HOT ARGGHH!
Do you lose pwr to the injectors, or does the low side just stop being pulled down to ground? On the N/A all the injectors are wired (and fired) together so you only need to ck one of them.
Normally the ECU will stop firing the injectors and stop energizing the fuel pump relay if it fails to see spark pulses. Do you have schematics?
Gdog- Thanks so much for pointing me in the right direction, it was the fuel injector relay (above the radiator), I had a voltmeter hooked up to an injector connector and noticed it jump to 12v when i tapped the relay, I thought the relay was good, but while doing what you suggested (checking to see if the injectors had 12v or if they weren't grounding), i figured it out... It had normal fuel pressure when it died of course to answer your question... THANKS
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