I have a '92 firebird with a 305. I diagnosed a problem with my ecm over the summer where it did not give an injector pulse. Now it works. However, every time the vehicle has been running for a period of time or the vehicle has been sitting in the sun the check engine light comes on but when i parked the car after driving it the light is not one. It only comes on if it is warm. I took a jumper wire to the DLC to get a code. When the light is not on the light flashes like it is suppose to. But if the vehicle is warm and the light is on the light does not flash. This is telling me I am not getting communication back from the computer even tho i know there is. It is very wierd and getting me frustrated cause im sick of knowing the light is going to come back on right after i shut the car off. I am thinking i have a short inside the computer causing it to come on. the vehicle runs rough when the light is on and i have to keep my foot on the gas. Any one ever have this problem?

anyone know of where i can get a new good quality ECM

 

ANYONE have ANY ideas?!?!?!?!? How about where i can get a good ECM?

 

go to napa or some other parts store and get a reman unit. cost about 100 bucks give or take. Before you do that i would take it to someone who has a scanner of some type and take it for a road test just to make sure that it is the computer.

 

Thats the problem you can hook a scanner up to it and pull codes when the light is on. It does not have any communication with the computer. If the light is not on it works fine. The computer in it is new from NAPA. The car did not have this problem prior to putting this new computer in the car. I think i got a garbage computer. I paid 80 bucks for it. I would rather buy a computer from someone else that is a well known company that i would be able to get a trusted good quality computer.
----------
Sorry, ment to say cant pull the codes when the light is on. You can only do it if the light is not on. I am able to get a hold of scan tools since i am an automotive student and work on cars all the time and work at a garage. like i said when you hook the scan tool up it says no communication with the ECM when the check engine light is on. IF the light is off than it is fine.

 

Remember the operative word is remanufactured.You can also substitute the word repaired for that.Maybe they fixed it,maybe they didn't.The fact that it works for awhile likely means they gave it a quick test and it seemed fine and they sent it out.I work with stuff that uses alot of remanufactured circuit boards and we go through runs where we have 30-50 percent of new board failures.I would bet almost anything that you simply have a bad new part.I had a ecm problem with mine not too long ago where it wouldn't flash anything back at me at all and sure enough it was a bad ecm.If there is power to the ecm and the communication lines are there to the diagnostic port it should flash something at you.If it doesn't change out that ecm again.

 

Thats what i figured. But since its a part that is non returnable no matter what it really sucks. Now im looking for a good place that makes quality ecm so that i dont have to worry about reman parts from napa. Dont feel like giving them another 100 bucks for a part that could be bad. I also did a continuity check from the dlc to the ecm, so it is definetly not a problem with the wiring. So now i need to get a good ECM. Anyone know where to find one and not NAPA?

 

When i got the ECM the first time they offer 2 differnt ECM's for my car. I know you have to look at the number on the ECM. But what is the difference between them and will either one work? Any other ECM's from prior years that would work? Any ideas how i can find this out?

 

I think napa has a fairly good warranty at least from what I remember when I changed mine.Don't try to return it to get your money back,return it as a new defective.That way at least you can con them into getting you another computer.Hopefully one that works this time.

p.s. I was working on a fairly expensive piece of electronics hardware the other day and I had to go through 3 supposedly rebuilt boards to get one that actually worked.