Killing ICM's?

[gmcyukondriver]

Hey guys. So lately, my truck has had a starting issue. I've had to crank it 2 or 3 times to get it to start. The starter and battery are both new and good. It cranks just fine, it will not fire. I replaced the ICM a few months ago, and I'm thinking it's gone bad again. Going to check it later.

Is there anything that could make it go bad so quickly? I've heard that old plug wires or a bad pick-up coil could wear them out. Is there anything else? Any other ideas what I should check?

Sometimes when I start it, I can tell it has fired, but it almost seems like it's going to die until I turn the key back from start to run, then the idle raises to where it should be. It's strange. Does this sound like ICM? And yes, I used dielectric grease when I installed the new one.

 

[96-1500]

Truck year/motor?

 

[great white]

Have someone turn the truck over and you watch the injectors.

If they're not firing, the ICM is suspect.

Not the only thing is could be, but one of them.

If the Injectors are firing, the ICM is at least performing it's duties.

Another possibility is one of the injectors is leaking down after shut off. This can cause a rich condition on the next start and needs a few cranks to clear it.

 

[gmcyukondriver]

1995 with TBI 350

Thanks BJ, I'll take a look at that. I never had a problem with it when it was stock. I'm thinking that it's possible that the Whipple killed the last one with heat buildup, and this one is either bad, or has had the same problem. Either way, I'll take a look at the injectors and report back.

 

[great white]

1995 with TBI 350

Thanks BJ, I'll take a look at that. I never had a problem with it when it was stock. I'm thinking that it's possible that the Whipple killed the last one with heat buildup, and this one is either bad, or has had the same problem. Either way, I'll take a look at the injectors and report back.

Heat will kill electronics sure as shootin'.

I would expect other that are whippled to have the same issues if that were the case though......

 

[thunderstruck]

What brand are you using? I would only use GM here, or AC Delco, which is still the actual GM part AFAIK.

Might be a good idea to check both your ignition coil and pickup coil with an ohmmeter. Sorry, IDK how to do that off the top of my head though.

 

[IOWNJUNK]

Did you put grease under the icm? It acts as a heat shield and helps it last longer, heat kills that $50 POS part.

 

[Ruger_556]

No experience at all with this but does the ICM control any relays? One thing that will kill a computer is if the spike suppression circuit (Diode is usually used) in a relay fails. I can't really help with your problem but as far as the computer dying in short order you may look at that. Heat is the other one that will do it.

 

[great white]

Did you put grease under the icm? It acts as a heat shield and helps it last longer, heat kills that $50 POS part.

<ahem>

check first post

 

[IOWNJUNK]

<ahem>

check first post

I even read this entire thread twice to see if anyone mentioned it...........





Might need to see my optometrist again.