4.3 tbi dying when hot

[TheAutumnWind]

Not really you'll feel a surge or jerk. What it does is create an electrical impulse that the ECM sees as high RPM so it loads more fuel momentarily. I also got code 45 - O2 running rich sometimes.



TunerPro RT v5 you can data log, monitor real time, see malf codes, and modify bin files.
http://www.tunerpro.net/downloadApp.htm

ALDL cable (12 pin for 88 - most 94s, 16 pin for 95s)
http://aldlcable.com/aldl.asp

And a laptop, you'll need definition files for your ECM/PCM
http://www.gearhead-efi.com/gearhead-efi/def/

And some research learning how to
http://www.gearhead-efi.com/Fuel-Injection/forumdisplay.php?27-TunerPro-Tuning-Talk

Thanks! Very helpful.

It was killing me I couldn't use my blue driver obd2 scanner on this truck.

 

[TheAutumnWind]

Not really you'll feel a surge or jerk. What it does is create an electrical impulse that the ECM sees as high RPM so it loads more fuel momentarily. I also got code 45 - O2 running rich sometimes.



TunerPro RT v5 you can data log, monitor real time, see malf codes, and modify bin files.
http://www.tunerpro.net/downloadApp.htm

ALDL cable (12 pin for 88 - most 94s, 16 pin for 95s)
http://aldlcable.com/aldl.asp

And a laptop, you'll need definition files for your ECM/PCM
http://www.gearhead-efi.com/gearhead-efi/def/

And some research learning how to
http://www.gearhead-efi.com/Fuel-Injection/forumdisplay.php?27-TunerPro-Tuning-Talk

The rpms aren't actually jumping that high the computer just thinks that they are which causes it to dump fuel.

 

[PlayingWithTBI]

The rpms aren't actually jumping that high the computer just thinks that they are which causes it to dump fuel.

That's right, the locked TC won't allow the engine to spin that fast, you'd be spinning the wheels at 60MPH, LOL

 

[TheAutumnWind]

Swapped to a United brand ICM. seems to have solved the problem. It has sat in stop and go traffic in 95+ F. No issues since.

 

[DerekTheGreat]

Swapped to a United brand ICM. seems to have solved the problem. It has sat in stop and go traffic in 95+ F. No issues since.

You still notice that tach fluctuation?
My truck does this when first started no matter what. It twitches about 2-400 rpm on and off for about two minutes and then doesn't do it again until the truck is shut off and restarted. I've been suspecting the ICM but since it runs just dandy I'm too lazy to start testin'. It ain't broke so I ain't gonna fix it yet.

 

[PlayingWithTBI]

Swapped to a United brand ICM. seems to have solved the problem. It has sat in stop and go traffic in 95+ F. No issues since.

Good to hear you got it. More and more times I'm reading about the ICM being the root cause. They don't seem to hold up very long and cheap ones way less. Did you use the thermal compound too? If not IMO you should remove the ICM, clean under where it goes and spread a layer of the stuff on the bottom of it. Keep clear of the mounting holes and don't over-tighten the bolts.

 

[TheAutumnWind]

You still notice that tach fluctuation?
My truck does this when first started no matter what. It twitches about 2-400 rpm on and off for about two minutes and then doesn't do it again until the truck is shut off and restarted. I've been suspecting the ICM but since it runs just dandy I'm too lazy to start testin'. It ain't broke so I ain't gonna fix it yet.

Yeah the tach flutters occasionally still. Im guessing that is tach or sensor related.

 

[TheAutumnWind]

Good to hear you got it. More and more times I'm reading about the ICM being the root cause. They don't seem to hold up very long and cheap ones way less. Did you use the thermal compound too? If not IMO you should remove the ICM, clean under where it goes and spread a layer of the stuff on the bottom of it. Keep clear of the mounting holes and don't over-tighten the bolts.

Thermal compound was applied, and the area was cleaned. I've installed some cpu coolers in my day so thermal compound application wasn't a problem. Dried up compound was likely the cause of the failure I think.

I do intend to replace cap and rotor sometime in the near future so I'll probably apply some better compound when that happens.

 

[sixteenacrewood]

My bet is spark control module inside distributor.
Be careful applying the grease to the back of it, follow directions.

 

[PlayingWithTBI]

More and more times I'm reading about the ICM being the root cause. They don't seem to hold up very long and cheap ones way less. Did you use the thermal compound too? If not IMO you should remove the ICM, clean under where it goes and spread a layer of the stuff on the bottom of it. Keep clear of the mounting holes and don't over-tighten the bolts.

My bet is spark control module inside distributor.
Be careful applying the grease to the back of it, follow directions.

???