89 Grand Am Quad 4 2.3

BLBUTZKE

MEMBER
1989 ALL OTHER MAKES ALL OTHER MODELS

I have an 89 grand am with the quad 4 2.3. It's running rough and have determined through local advice that just the 2 middle cylinders are running, so I'm running on 2 not 4. Checked all coils, housing, spark plugs, etc. Thinking it's now maybe the ECM or Wiring Harness? Anyone able to shed some light on this? Car has about 130k miles on it, but it gets from point A to B and was hoping to get another year out of it. Is it worth putting in a different ECM? Can you find them used and is that even worth the risk?

5 Replies

PEPPERMRJ

MECHANIC
1,158 POSTS

ECMs are pretty solid on these cars.
If you were running on two cylinders the complaint would be much more than running rough.

What maintenece has been done lately? Plugs, wires, filters, etc? Check for vacuum leaks and proper fuel pressure. Have you tried some fuel injector cleaner? Also a leaky EGR can make for rough running.

Good luck and let us know? :)

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Friday, March 16th, 2007 AT 11:13 AM

MMPRINCE3000

MECHANIC
133 POSTS

Is it an ignition problem or a head gasket? Pressure test the cooling system to eliminate the head gasket.
Quad 4's had a severe head gasket problem.
If ignition you would have to check the coil paks wires and crank sensor.
You are pouring a lot of raw fuel in the engine if you are only running on two cylinders, it could cause main bearing failure, then your done.

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Friday, March 16th, 2007 AT 11:13 AM

BLBUTZKE

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2 POSTS

Update - yes, I've tried fuel system cleaner, not helping as of yet. Head gasket is fine. I've checked everything with secondary ignition, so I'm assuming it's with the wiring harness or ECM. And I should have said, running rough, with very little power. It is in fact the wiring harness or ECM, any guesses on approximate fix price? Or how do I narrow it down between the two - any good ways to check a wiring harness other than tracing every wire?

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Friday, March 16th, 2007 AT 11:36 AM

CATFISH

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1 POST

? I have one that is doing about the same thing you say your car is doing.I have to hold the gas to the floor to get it to run. It like im not geting the gas I need, im thinging its my fuel pump. But please let me know what you do to get yours running. So I can get my car running right

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Sunday, March 25th, 2007 AT 11:40 PM

MCFERRANCE

MEMBER
100 POSTS

Make sure to check the EGR valve. It may be staying open. Also when checking any electrical, always be sure to check any areas that may have been previously repaired. These are usually where the problem lies. With electrical connectors, always make sure the terminals are clean and spread them to make better contact when possible.