1988 - 1998 (GMT400) Section for all discussion related to the 1987-1998 Chevrolet and GMC trucks.

350 tbi runs great cold, dies when warm - help

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Old Nov 29, 2020 | 8:11 AM
  #21  
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Originally Posted by Rednucleus
After it dies, when you cycle the key to restart do you hear the fuel pump prime again?
yes and I even jumped the fuel pump to bypass the relay so that it runs continuously. It does, but truck starts and then dies after a few seconds or minutes (varies).
Always has spark, but injectors spray sometimes but not enough to keep it running. I have yet to test injectors as I'm waiting to get noid lights.
I just can't believe there is a fault with the tbi as it will run normal for a few minutes then dies because the tbi shuts down.
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Old Nov 30, 2020 | 11:02 PM
  #22  
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Originally Posted by Joe Winsor
yes and I even jumped the fuel pump to bypass the relay so that it runs continuously. It does, but truck starts and then dies after a few seconds or minutes (varies).
Always has spark, but injectors spray sometimes but not enough to keep it running. I have yet to test injectors as I'm waiting to get noid lights.
I just can't believe there is a fault with the tbi as it will run normal for a few minutes then dies because the tbi shuts down.
Did some research and this is what I found:

1. Defective water temperature sensor.

2. Possible O2 sensor problem.

3. A defect somewhere in your evaporative control unit or system.

I hope this will help you. Also you should be getting 6 to 12 PSI plus or minus to your injectors.
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Old Dec 4, 2020 | 6:29 PM
  #23  
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Still trying to solve this problem.
Always has spark.
tested fuel pressure. Steady 13psi.
cleaned rusty ground at thermostat
used Noid light to monitor injector pulse. Flash when it wants to run, NO flash after dying (still has spark)
Again, has brand new AC Delco distributor. I'm thinking there has a ECM issue,or a problem with the connection between ECM and the distributor that is making the pulse to the injectors die after a minute of run time.

Thoughts anyone?
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Old Dec 5, 2020 | 3:10 AM
  #24  
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Originally Posted by Joe Winsor
Still trying to solve this problem.
Always has spark.
tested fuel pressure. Steady 13psi.
cleaned rusty ground at thermostat
used Noid light to monitor injector pulse. Flash when it wants to run, NO flash after dying (still has spark)
Again, has brand new AC Delco distributor. I'm thinking there has a ECM issue,or a problem with the connection between ECM and the distributor that is making the pulse to the injectors die after a minute of run time.

Thoughts anyone?
At 30 years of age, sure your ECM could be on the fritz. Nothing lasts forever, not even the ECM. It's been through all kinds of heat and cold conditions and operated fine, but the day comes for us all, and an ECM is no exception, same as everything else on this planet.
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Old Dec 13, 2020 | 1:35 AM
  #25  
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Originally Posted by oilcanhenry
At 30 years of age, sure your ECM could be on the fritz. Nothing lasts forever, not even the ECM. It's been through all kinds of heat and cold conditions and operated fine, but the day comes for us all, and an ECM is no exception, same as everything else on this planet.
As it turns out, it was the wire pigtails to the ICM that were bad.
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Old Sep 3, 2022 | 8:42 PM
  #26  
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Originally Posted by Joe Winsor
As it turns out, it was the wire pigtails to the ICM that were bad.
Im having a similar issue in my 93 Chevy G20, my problem is I'm limited in my engine and vehicle knowledge, my brother helps me when he can. What did you fix or replace? I think I found the ICM checked the wires on it, they didn't look bad, didn't follow one all the way as it goes under the vehicle.
Im just trying to get a grasp on what to do next and wiring/electrical throws me for a loop
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Old Mar 29, 2023 | 6:25 PM
  #27  
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I have the same problem. Dies when warmed up. Why would the heatsink or module temp be an issue when it runs fine at throttle. Just dies at anything lower than about 1500RPM? My IAC is new and the port cleaned, the TPS tests out on the money, no vacuum leaks. It still has all the air pump anti smog stuff on it. New cap, wires, rotor, plugs - still think it's module? What does the engine temp sensor control? It must be working because things change as the engine gets warmer. So what gizmos does that control? IAC? and ?
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Old Mar 29, 2023 | 6:27 PM
  #28  
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Noid light? Do you mean Neon?
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Old Aug 12, 2024 | 5:17 PM
  #29  
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Default Cold starts good hot no good

Originally Posted by Joe Winsor
Hello. I have a 1990 350 tbi that runs great cold. After warms up it either dies or will not restart after shut down. Checked both spark and injector spray and nothing from both. Let cool off a couple hours and starts back up and runs fine until it's hot again, then is dead until it cools off.
ICM was replaced and still happens.
Any Help?
hi , I have experienced this issue twice lately….One an 88 tbi. v6 , the latest a 95 5.7 tbi. ..the fix is , drop in a new good quality performance distributor. The reluctor is probably the issue, it’s not worth taking apart in my opinion. You can if money is that tight. I’ve done it before. But a new distributor is easy quick fix. It has always worked for me . Good luck to anyone looking to address this issue.
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