ecm I think ?
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Joined: Sep 2004
Posts: 58
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From: Lisbon maine
ecm I think ?
I think my ecm is bad. I'll be driving the car for a few minutes, and then it dies.Then I have a hard time starting it again.When it does run the car will only idle at around 5... If I wait a little while it will start, but not for long. The ecm will not talk back to my scan tool.... and I have changed the maf and relays. Also has fresh plugs/wires. How did your car act when the ecm Sh** the bed?
Drifting
Joined: Sep 2005
Posts: 1,867
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From: Pasadena Maryland
I just replaced mine. The car drove and ran fine, no problems. The SERVICE ASR light was on and I got a flashing SYS light. The error codes were for LOSS OF SERIAL DATA. While I had a scanner on it sitting in the garage with a cold engine I would get intermittent errors for UNABLE TO COMMUNICATE TO CCM. The ALDL connector goes into the ECM. They are hard to find, GM Parts Direct canceled my order because there are none in the system right now.
Safety Car
Joined: May 2005
Posts: 3,682
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From: Scappoose Oregon
St. Jude Donor '11,'14
Mine had a tough time idling and you could smell fuel from the exhaust from running so rich. Mine did not have any codes. I took it to the Chevy dealer and the dealer replaced the ECM and then it worked like a champ.
Kevin
Kevin
Le Mans Master
Joined: Dec 2002
Posts: 6,715
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From: Santa Teresa New Mexico
In cases like these we usta keep several used good ecm's around the shop. They rarely fail but when theres a problem its hard to figgure it out without throwing money at it. Good used parts make the job a lot simpler.
Thread Starter
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Joined: Sep 2004
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From: Lisbon maine
Should I look for a used ecm first? If so, does it have to be from an 88' vette, or is there other years/gm cars that I could get one from?
Le Mans Master
Joined: May 2004
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From: Hellinois
Finalist 2020 C4 of the Year - Modified
ECM's can be heat sensitive so before you throw money at it try this. Get an ice pack, one of the small ones in a plastic bag. Freeze it and place it against the ECM to keep it cool. Go out and drive the car, if it doesn't act up then you can be fairly sure it really is the ECM. My '85 acted much like yours is and I had tried everything until I found out about this tip. I changed the ECM and it has been fine ever since.
Advanced
Joined: Aug 2005
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From: Little River SC
Another test is to tap on it with the handle of a screwdriver with the car running then when the car won't start try tapping on it to see if it will start. Bad or broken solder joints are common with them.
I got one at Auto Zone. About $100 with core.
I got one at Auto Zone. About $100 with core.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
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From: Louisiana
You can use a 86-89 ECM (89 being the best). The ice pack on the ECM "trick" works best with the 90-96 where the ECM/PCM is under the hood. It's very tight under the dash of the 84-89, and an ice pack would be very difficult. I haven't tried it, so it might be doable.
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