1990 3.1L Lumina - My Problems

[mattsdominion]

Well, for starters... i'm new to the forums. This is my first post.

I have a 1990 3.1L with 118k miles on it. I got it with 90kmiles, from my grandmother for like 500.00 dollars.

I've since done the following to it:
Rebuilt tranny, new catalytic converter, new rear calipers.

three weeks ago, i started having serious trouble with it. The engine would jerk, and it was running real rough. Finally, it stalled out on me.... and wouldnt start.

I've since changed out the following parts:

O2 sensor, MAP, IAC, TPS, PCV valve, PCV hose, all three ignition coils, ignition module, all 6 spark plugs, all spark plug wires, a new system computer, replaced all the wire loom, which was dry rotted, replaced the ECM ground lead, throughout the entire car... which had a short in it.

And then i made the car re-learn idle. The car is stalling when you give it gas... which leads me to believe that the timing chain, which was original is now worn... and has slipped a few teeth. I'm in NY, and i had a local auto shop order it overnight for me. I'll be changing it out tomorrow night.

I absolutely love my lumina, and next major repair is going to be the struts, and shocks. As well as the rear leaf spring. I have some minor body damage, which is going to be fixed after i get new tires on the car, and fix the suspension.

I plan on keeping a running log in this thread.

Anyone with a 3.1L V6, can ask me whatever questions they want... I have full wiring diagrams, and repair manuals. I personally diagnosed and fixed my problems as they occured with a Snap-On OBD scanner.

I will eventually provide a full error-code list, as well as some wiring diagrams. Other stuff upon request.

[jeffcoslacker]

I seriously doubt you've slipped a timing chain this early. I've seen these run to 175,000 and more without the gears rounding. But let us know what you see in there.

They were more prone to rolling idle when the chain stretched or slipped.

I'd bet on a fuel delivery glitch, since you've covered the rest.

[mattsdominion]

For whatever reason, my dad and his mechanic think that the problem doesn't lie in the timing chain either.

I just recalled, that smoke came out of my steering column about a month ago. I don't know why i'd dis-regarded that... I have narrowed it down to not being the horn, the hazard lights, the windshield wipers, or the turn signals. The cruise control works too... What else is in the steering column that might have caught fire, or cooked and smoked?

[mattsdominion]

Originally Posted by jeffcoslacker

I seriously doubt you've slipped a timing chain this early. I've seen these run to 175,000 and more without the gears rounding. But let us know what you see in there.

They were more prone to rolling idle when the chain stretched or slipped.

I'd bet on a fuel delivery glitch, since you've covered the rest.

The fuel pump has solid voltage going to it.. it isnt cutting out.
and i have consistent fuel pressure on the fuel rail, and down the entire line.

Could i possibly have cooked the actual ignition? And what effect would that have had on way the car runs?

After resetting idle, the car runs relatively smoothly... still slightly rough, with some vibration. As soon as you give it gas, it dies. The TPS is reading correctly. I had a system scanner plugged into the diagnostic port. Everything seems to be reading within the acceptable range...

I'm not getting ANY engine codes. I'm wracking my brain here.

[tblake]

Jeff, didn't you say something about a bad coolant temp sensor causing the 3.1's to run bad? Maybe try there. Otherwise if i were you matt, I'd look into the fuel injectors. Do a balence test on them. You are probably familiar with this, so I'm not gonna go into detail. Replace any that seem out of range of the others. Or maybe just replace them all. Also I'd replace the fuel filter too. That may be part of your problem. Good luck. Welcome to AF!

[jeffcoslacker]

Originally Posted by tblake

Jeff, didn't you say something about a bad coolant temp sensor causing the 3.1's to run bad? Maybe try there. Otherwise if i were you matt, I'd look into the fuel injectors. Do a balence test on them. You are probably familiar with this, so I'm not gonna go into detail. Replace any that seem out of range of the others. Or maybe just replace them all. Also I'd replace the fuel filter too. That may be part of your problem. Good luck. Welcome to AF!

Yeah, I've seen CTS for the ECM go bad and make it command some really weird fuel mix ratios.

It seems when this happens, the problem is not bad until the motor warms up, or bad when cold and better with temp, as the incorrect ratio starts to be closer or farther from what the motor actually needs for the temp at the time.

[mattsdominion]

Originally Posted by jeffcoslacker

Yeah, I've seen CTS for the ECM go bad and make it command some really weird fuel mix ratios.

It seems when this happens, the problem is not bad until the motor warms up, or bad when cold and better with temp, as the incorrect ratio starts to be closer or farther from what the motor actually needs for the temp at the time.

hmm, well i'm going to check some more of the wiring in the interior of the car... i had a problem with my dimmer and light switches. I might have more interior wiring problems too... and there might be a major ground short possibly in there.

I'm noticing that my injectors are being shut off when i give the car gas, for whatever reason... i have a test light plugged into the harness where the first injector is. I think something is shorting out still... i'm almost at a loss of where to look.

I'm going on nearly day 10 of not being able to drive the damn thing. I absolutely love the car, and i can't wait to have it back on the road... It's always treated me well... and is comfortable as hell to drive and ride in.

I'll post more tonight, when i am done playing around with some more wiring. and btw? The snap-on scanner is reading acceptable temperature ranges... I guess i can do a printout of how it's all running... but all the sensors seem to be functioning correctly, now that the idle was reset. I'm not getting any error codes, which is making me nuts. It's hard to diagnose it, without any codes coming up... its just that the car dies when you step on the pedal. I still think it's electrical... but it could be a failed sensor that i didnt change yet... that is failing when i give it gas... but not when the car is at idle. I'm stumped. I'll check out just about anything to get this damn thing working.... I have the tools. I can do it, i just need to know what to look for.

[mattsdominion]

on a whim i pulled off my serpentine belt....

guess what? The car ran beautifully... and didnt stall when i gave it gas. Harmonic Dampener... i have to drop my engine down a bit, and put the car on jack stands. Then use a puller to pull the crankshaft pulley wheel.

I'll keep you guys posted on my progress with the crankshaft dampener.

[jeffcoslacker]

I'm confused. The balancer wouldn't make it die, and turns whether the belt is on or not.

[mattsdominion]

Originally Posted by jeffcoslacker

I'm confused. The balancer wouldn't make it die, and turns whether the belt is on or not.

the housing behind it, the plate. It might have slipped... causing it to rub, and catch when there is tension on it from the pulley... it moves nice without a load on it, but once there is tension on it... it messes with the crankshaft sensor readings and crap like that...

I'm waiting for a three jaw puller, i'll keep ya posted.

[jeffcoslacker]

Originally Posted by mattsdominion

the housing behind it, the plate. It might have slipped... causing it to rub, and catch when there is tension on it from the pulley... it moves nice without a load on it, but once there is tension on it... it messes with the crankshaft sensor readings and crap like that...

I'm waiting for a three jaw puller, i'll keep ya posted.

Ahhh....that makes sense. Weird. Never seen that one.

Kinda reminds me of the old Mopars with the dual belt A/C compressors. If you were pretty strong, and put a hell of a lotta tension on those belts, the crank mains would knock from all the sideload.

[mattsdominion]

pulled it off... everything seems pretty normal...

I'm at a complete loss here...

What else could be causing the car to stall out, when the belt is on... but not when the belt is off...

[paulfischer]

Have you replaced the fuel filter?? Have you checked the fuel pressure regualtor?
Maybe you have an injector or 2 going bad.
Maybe a faulty IAC? Did you get a GM one or one from Autozone? I got one from Autozone, and it came apart in the throttle body..........

Keep us posted.

[mattsdominion]

Originally Posted by paulfischer

Have you replaced the fuel filter?? Have you checked the fuel pressure regualtor?
Maybe you have an injector or 2 going bad.
Maybe a faulty IAC? Did you get a GM one or one from Autozone? I got one from Autozone, and it came apart in the throttle body..........

Keep us posted.

fuel pressure is a go...
fuel filter is less than 2 weeks old.

The IAC came from NAPA, and i've never had a problem with NAPA parts, ever.

I went over the ECM ground wiring again... and determined that the one going to the A/c sensor was also bad... so i've finally replaced EVERY ECM groundwire. My car isn't giving off any engine codes....

I am noticing a problem with my throttle though... it seems to be catching, or binding or something.

When you start the car, it idles nicely... put it into drive, or reverse, and it runs somewhat rough.... you can give it gas up to about 1600rpm, if you accelerate slowly... and then the car seems like it wants to die if you give it any more gas than that... if you floor it, the engine stumbles and tries to die... but doesn't stall out. seems like it's running really rough when you do that.


I was told by a GM mechanic friend of mine, to check the timing chain and the crankshaft position sensor.

seeing as how the car has 120k on it, i'm going to do the timing chain either way. The crankshaft position sensor, can go bad in stages i've heard, and from what i've read about it as well.

Trying to fix this, is like looking for a needle in a haystack.

[jhouston77]

I had my CPS go out in January. It just stopped and wouldn't go at all. I also have 1990 lumina 3.1 liter and your problem sounds exactly like mine. My car will start and idle just fine. you give it gas though and it just will stall out. I have replaced the fuel pump, fuel filter, fuel screen, tried a new computer, tried a new ECM. all this and the problem remains. I hop0e you solve your problem. Maybe it will solve my problem.