87' R10 TBI 350 shuts off when driving. HeLP

[Hunter_Michael]

Mine just Cut out and died completly while my son was driving it today...Again.... The LED light connected to the coil stayed on when it happened. Now when I crank the engine the injectors will not spray fuel. Have verified the fuel pump(s) are working and the fuel Pump soleniod is clicking as well. All fuses are good. Had to tow it home. I pulled the fuel filter line off to verify the pump was pumping fuel, which it was and also checked injectors with a 9v battery and both are clicking open. Also pulsed the wire harness with a test light. one side was pulsing the other side didnt however when you crank the engine I can feel air pulsing out both injetctors but no fuel? What should I check now?

 

[gmbellew]

Mine just Cut out and died completly while my son was driving it. The LED light connected to the coil stayed on when it happened. Now when I crank the engine the injectors will not spray fuel. Have verified the fuel pump(s) are working and the fuel Pump soleniod is clicking as well. All fuses are good. Had to tow it home. I pulled the fuel filter line off to verify the pump was pumping fuel, which it was and also checked injectors with a 9v battery and both are clicking open. Also pulsed the wire harness with a test light. one side was pulsing the other side didnt however when you crank the engine I can feel air pulsing out both injetctors but no fuel? What should I check now?

check for spark while cranking. if you have no spark, follow the ignition check. if you have spark, follow the injector check chart A4

this is starting to smell like an ICM going bad to me, a bad connection at the ICM, or maybe a ICM harness wire that has rubbed through somewhere.

 

[OllieJay87]

I had a similar issue after replacing almost everything. No codes no hesitation just dead on the road. After truck cooled it would start again. I figured out the oil pressure sensor was losing continuity after it heated up. It would open the circuit and cut out fuel and in turn spark. Replaced it and that issue was solved. Rigged up a test with compressor, meter, and heat gun to prove old ops was issue. Maybe this will help.

 

[Ricko1966]

I had a similar issue after replacing almost everything. No codes no hesitation just dead on the road. After truck cooled it would start again. I figured out the oil pressure sensor was losing continuity after it heated up. It would open the circuit and cut out fuel and in turn spark. Replaced it and that issue was solved. Rigged up a test with compressor, meter, and heat gun to prove old ops was issue. Maybe this will help.

If this fixed a TBI vehicle you had 2 problems.The oil pressure switch is a redundant circuit, in case your fuel pump relay quits functioning, the car will still run on the redundant circuit so you aren't stranded. Not saying it's not his problem just want to clarify to anyone,if the oil pressure switch makes the car run again, you still have the primary circuit to troubleshoot. It's like driving on the spare tire until it goes flat,you need a new spare but you also need the original tire replaced.

 

[OllieJay87]

Thanks. I hear you on this. Still slowly working out all my issues. When I got truck it hadn't run in years. Diagnosed a short in original ecm that was continually blowing fuses. Truck was a mess. Still kinda is.

 

[Hunter_Michael]

sorry dbl post

 

[Hunter_Michael]

Just pulled the distributor to replace the pickup trigger coil and noticed the ignition coil connector pig tail (black Connector) had a bad connection on the white wire. It was barely hanging on, I bent it and it came off.. So I think I may have found my issue or another issue that just happened when investigating wiring.
Would this stop injectors from firing?

 

[gmbellew]

Just pulled the distributor to replace the pickup trigger coil and noticed the ignition coil connector pig tail (black Connector) had a bad connection on the white wire. It was barely hanging on, I bent it and it came off.. So I think I may have found my issue or another issue that just happened when investigating wiring.
Would this stop injectors from firing?

I am guessing that's your problem....

 

[Hunter_Michael]

I am guessing that's your problem....

I sure hope so. I just installed the distributor back in with the new pickup coil and also noticed one of the (two) distributor cap bolts that hold it onto the distributor was stripped... re taped one size larger bolt and got it secured properly. That could of been amother issue as well... Only had the vehicle for a couple months and chasing all the issues down from the previous owner one at a time lol...

I put cylinder one at TDC when putting in the dizzy and lined up spark plug 1 one the cap with the rotor, is there any special things I need to do thats different then other vehicles? I know I have to disconnect the one wire when setting timing then reconnect.

The new ignition coil wire pigtail wont be here till Thursday so hopefully get to fire it up then, crossed fingers it fires...

 

[gmbellew]

Sounds like you are on the right track. I've had my 90 suburban for 6 years and just now feel like I have all those sorts of issues sorted out. There is a lot of things just getting to start going wrong when it's all 35yrs old, even if it has been well taken care of.

 

[F-64]

Actually, nevermind I hadn't read all the way through the posts..

 

[Hunter_Michael]

Ok, issue now. I took the old pigtail and got it spliced to temp work while waiting for the new one to come. Was seeing if I could get it to start. Now what I have is still no fuel thru the injectors. Got power to the red wire on both with key on on the injector harness plug, Test light confirms. If I ground the other terminal while its attched with key on it sprays fuel thru the Injectors. But wont spray unless I intentionally ground it?? What controls or triggers the injectors ground or? Stumped..

 

[gmbellew]

Ok, issue now. I took the old pigtail and got it spliced to temp work while waiting for the new one to come. Was seeing if I could get it to start. Now what I have is still no fuel thru the injectors. Got power to the red wire on both with key on on the injector harness plug, Test light confirms. If I ground the other terminal while its attched with key on it sprays fuel thru the Injectors. But wont spray unless I intentionally ground it?? What controls or triggers the injectors ground or? Stumped..

injectors ground through the ECM. follow the charts I posted earlier. check for spark. if you don't have spark, diagnose that. if you have spark, then diagnose the injectors not firing.

 

[squaredeal91]

Ok, issue now. I took the old pigtail and got it spliced to temp work while waiting for the new one to come. Was seeing if I could get it to start. Now what I have is still no fuel thru the injectors. Got power to the red wire on both with key on on the injector harness plug, Test light confirms. If I ground the other terminal while its attched with key on it sprays fuel thru the Injectors. But wont spray unless I intentionally ground it?? What controls or triggers the injectors ground or? Stumped..

Make sure there is some sort of electrical grease on the icm. I've found them installed dry by mistake before.
Don't ask what to put on it. I've seen it go for 30+ pages and I don't think it's worth the hassle lol.

 

[Hunter_Michael]

I got tired of following the troubleshooting guide after going about 3/4's the way thu it and finding nothing wrong... So I just replaced the distributor coil like was told earlier and also swapped the ICM just because I had the extra ones in a box. It Started... I wonder if the new (standard) ICM went bad?? But happy to say it is running again! Now have to do the timing and button it back up! Hoepfully what ever I did fixed the random cut out while driving! And will replace the pigtail to the coil when it arrives on Thursday!