1990 lumina, doesn't start/goes out, lights flickering, relay clicking

[jdiron]

Hello, I'm new to this forum and I'm searching for help with a problem with my lumina. It's a 1990 lumina euro sedan with a 3.1 engine, about 42000 miles.

The problem is kind of strange:
- When I turn the key to ON the "low coolant" and "service engine soon" lights turn on and off and I can hear a clicking of some relay near the intake manifold on the engine.

If I try to start, what happens depends:
- if the "low coolant" and "service engine soon" lights have stopped flickering and stay on, then the engine starts;
- if however they continue flickering or stay off, then the engine doesn't start.

If the engine does start and work, after about 1 to 5 minutes it just stalls and goes out. Then again, the "low coolant" and "service engine soon" lights flicker, the relay near the intake manifold clicks, and the motorfan also goes on and off.

I only just bought this car, but I have been driving it 160miles non-stop without any problems before this problem arose. I believe someone else one this forum also had this problem 3 years ago, but they never posted how or if they solved it.
Does anybody have any idea whats wrong with my car? Is it maybe the ECM? I'd greatly appreciate any help. Thank you in advance.

[jeffcoslacker]

I'd start by checking all engine and chassis grounds very carefully...

[jdiron]

Hi,
I checked the groundings and indeed found that the negative battery cable was slightly loose because the thread in the aluminium battery grip has pretty much dissolved, but I got all that fixed and exchanged the battery too.
However, my problem hasn't disappeared:
After connecting the battery, I start the engine and everything is fine. After four minutes, however, the engine runs more rough and the rpm goes slightly down, until after another minute the engine completely halts. Then, the IAC (I think thats what its called) opens and closes, the fans go on and off, and the service engine soon light goes on and off together with the low coolant light.
I turn the key to off and then back to on and the IAC, fans,and SES and coolant light continue going on and off. Starting the engine then is impossible. I have to wait a couple of minutes and then the engine can be started again and the problem continues from the start.

I have tried to check the codes, but all I get is code 12 (which means everything is fine). The funny thing is that sometimes, even when I am not trying to check the codes (I check by using a jumper wire between diagnostic terminals A and B), the service engine soon light still signals code 12.

Any ideas what's wrong? I had the battery disconnected for quite some time, so does the ECM maybe need to relearn to idle? Or is this a sign of a defective ECM?

Thank you.

[jeffcoslacker]

It almost sounds like the ECM is shorting and going into a diagnostic mode spontaneously...

I'd say the bad ECM is a good bet, or it's ungrounded and freaking out...just for grins try connecting a jumper cable from the neg battery post to the engine, and then connect the other cable from the engine to the body..then see what happens...sometimes this stabilizes the ground for the whole car and things start working right...then you gotta find the broken grounding strap or wiring that's causing the problem. It's a long shot, but quick enough to do...

Ask Richtazz if you have one of the problem ECMs...

[richtazz]

For others reading this thread with a similar problem.

jdiron PM'ed me with his ECM service number (1227727), and it is the problematic one. This ECM is known for water intrusion issues due to it being mounted under the hood in the right front fender area, that will cause random dying/no-starts and/or funky check engine light behavior (no codes, ghost codes, random flashing, etc...).