1990 Pontiac Trouble

[my85olds442]

1990 pontiac bonneville 3.8 75,621 miles. This is my Daughters car that she got two weeks ago and it would not start the other day. I went over and it started after I pumped the gas a few times but it ran rough. The first thing I did was change the fuel filter (and a bunch of fuel line) and the air filter. I also installed new plugs (gapped at 60, the ones I took out where anywhere from 28-37?) and new wires. It did start and run fine - for a day or so.. then the same non-starting issue again... the next thing I did was check the ICM and coil pack. The ICM was completely melted with green goo running all over so I replaced it and guess what? she ran like a charm again - for a day or so... Next I checked the fuel pressure and it seemed a bit weak so I changed the fuel pump and almost the rest of the remaining lines and it ran great, for a day or so... So today I stared thinking that if the ICM is bad the coil pack may be bad also.. I had it tested and it was bad and the car startd and ran fine for about 20 min and now it is running rough again. when it runs rough it is running VERY rich so I though low spark but I guess that is not the issue..
Vac lines are all OK and tested with starting fluid.. good fuel pressure.. good spark..
I will check the firing order just to make sure the previous owner did not mix 'em up but I think it is OK as it runs fine at times....
So any thoughts on what I should look at next? Any ideas why the ICM would be melted?
I am startin' to get sick of throwing parts at it with no improvement lol..
Thanks folks!
Stefan

[Malachias]

Look for the Lambda plug ; if bad make the engine run rich.
It´s cheap and you can trade it youself.
Good luck.
Malachias (brazil)

[my85olds442]

Lambda plug?

[Jrs3800]

You are in a tricky place my friend... The problem you have could be a number of different things..

Has the SES light come on and stayed on at all?

The issues you are having could range from the ICM to the ECM itself, O2 sensor, MAF sensor... On and on... Its really hard to say..

For the ICM, generally when we have an older 3800( 88-91 ) that has a melted or a need to be replaced ICM we just upgrade to the Delco Type 2 System which has a hotter spark..The melted unit you are describing is the Magnavox System...

It sounds like the car runs good until it warms up... This would be a car I would love to throw a Scan Tool at, and thats so that we can see what the inputs are from the sensors, as well as the ECM controlled actuators... Do you know of anyone with a Scan Tool that can read your car?

[my85olds442]

"Has the SES light come on and stayed on at all?"
no, no SES light at all

"It sounds like the car runs good until it warms up..."
well it did seem that way but now it runs rough as soon as you start it..

MAF sensor "looks" new and did pass the "tap" test..

"Do you know of anyone with a Scan Tool that can read your car?"
No, but I am thinking of buying one soon if I can't think this thing out...

thanks folks!

[Malachias]

Lambda plug = O2 sensor

Malachias

[my85olds442]

Ahhh, I have never heard it called that before. lol, I guess ya learn somethin' new everyday 'round here...THANKS!
Well I guess I might as well change the old Lambada (o2 sensor). It's worth a try anyway.. I am also thinking temp,crank or cam sensors? how about the EGR? The one thing that I did NOT change is the PCV yet (I will change it tonight) but I don't think it could make it run that bad but who knows...

[maxwedge]

All guess work, Jrs3800 is giving you the correct advice here.

[my85olds442]

Yes, and a big THANKS to all of you who have helped me with this issue! I am going to replace the MAF next.. I cleaned it and it did seem to run a bit better so I hope I am on the right track here!! I will let you folks know how I make out.
Thanks again folks,
Stefan

[my85olds442]

Oh, BTW I did change the 02 sensor & PCV with no improvment.. at the very least this car will have a bunch of new parts the we should not have to worry about any time soon lol..
Thanks again folks!

[jdq]

Did you try cleaning the IAC valve at least it dont cost anything.I would try and get a cheap ECM from junkyard.

[my85olds442]

The ECM is brand new. (it was melted)
I will try to clean the Idle Control valve and replace the MAF tonight and let you folks know.
THANKS!

[my85olds442]

success! I replaced the MAF last night and she is now running 100%! Thanks again to ALL that helped! you guys ROCK!!
(I MUST buy a scanner before I work on any more "new" cars..
-I know this is a bit off topic here but do any of you have a suggestion for one to get?
feel free to drop me email if you do...)
Stefan
([email protected])