Car is driving me up a wall!

[Redfallon]

I'm not normally one to go this far off topic and ask a question about my vehicle here on the mech, but this one is driving me up the wall. Hoping someone out there has dealt with something similar or knows a little more about cars than I (I don't know everything, but I get around 'em pretty well!) Anyway, friend has a 1994 Pontiac Grand AM SE, 2.3L SOHC quad-4, 75,000/engine 125,000/remainder (long story there, ehh?) The vehicle will randomly stall. Sometimes at a red light, sometimes under acceleration, sometimes coasting downhill. Sometimes will start back up right after stalling, sometimes cranks and cranks but has to "take five" before she'll fire up. Putting the car into neutral and/or revving the engine doesn't seem to help, if it wants to stall it's going to stall. Check engine light stays on, engine oil light flicks on/off intermittently when running. 1994 so should be OBDI however I can't get any code(s) to display. Taken it to a shop a friend of mine owns and no code on their machine. Got a OBDII scanner coming sat from another friend as someone told me it *may* work being a 1994, as I thought OBDII was 1995+ I've driven the wheels off this thing the last week and there seems to be no rhyme or reason to the stalling, but it's progressively getting worse. Occassionally the throttle almost seems to "stick" for a couple seconds after letting off the pedal, doesnt appear to be mechanical sticking.

I've checked the following: injectors, checked for spark, checked for trouble codes, reset computer

I have also replaced the following: Fuel filter, fuel pump, O2 sensor, air filter.

Now for the twist ;) I *believe* this car has been underwater. A Carfax report comes up clean, but 1)there is *alot* of evidence of gritty, sandy dirt in places it should *not* be IMHO, and 2)the person who bought the vehicle gave it to my friend who was "sans wheels" due to an accident, said he "got it cheap, but had the engine replaced because it looked "rusty". There is also rust/sediment in the cig outlet. :(

I am currently considering the following, awaiting my OBDII scanner Saturday morning: EGR valve, ignition coils/housing (~$110, have heard/read these can be faulty on this engine), ignition module ($150.00), or engine control computer ($85~95, considering the general consensus that the thing's been under water, and won't seem to give a fault code)

All of these items are increasingly expensive, the person who's vehicle it is doesnt have a ton of cash laying around, so a new car is out right now, and guessing and replacing part by part is difficult. I've got the cash to start replacing parts, but 1)would prefer what can remain in my pocket does and 2)don't want to replace stuff that's a-ok! :( And as yet I have been unable to run down with any certainly the cause of the problems. If anyone has any ideas I would really really be grateful, if not, hey at least I got a chance to vent as this one is seriously driving me nuts...and it's not even my car!

[Propain]

my reply was gonna be the Oxigen sensor but I see youve already replaced it. my dad had the same model and it did that till he changed it eh

[Redfallon]

quick question there propain, did it take a little while after replacing the O2 sensor for the engine to recalibrate itself and work itself out? or was it like, boom, fixed? Although I've put ~100 miles on the thing since replacing that and it seems to be getting worse, got better for a day and then slipped back downhill

[Propain]

it was the problem . went away BOOM fixed.

[HAL9000]

Check for the recall notice.. there was some connector that allowed moisture in that would cause rough idling and stalling.

[Redfallon]

Thanx Hal, unfortunately the only recall information I've been able to find relates to possible ignition circuit overvoltage and inadequate welds at the fuel tank causing leaks in rear end coll's. Maybe a Canadian recall on that? ::shrug:: keep em coming guys :) I recently found out it could be the TCC solenoid (torque converter control) but this usually only causes stalling when slowing down after driving above 30~50MPH, and is similar to "slowing/stopping a manual tranny and not depressing the clutch" which isn't really close to what mine is doing. Easy check on that one, disconnect the cable to the TCCS and see if problem goes away. Did I mention I hate electrical problems! thanx again!

[Spartan]

I would think it would be the computer. Is it mounted under the drivers seat? With all of the evidence of water I would at least try to open the case and look at it (if it can be opened on that model). It is the randomness that makes me think that. If it only stalled at light or when idling in gear I would say look for heat issues. If it only stalled under accel/decel I would say check ignition electronics/hardware. But with most of the totally random problems I have seen like this it was computer related.

If you really really really think it has been under water then I would advise him to get rid of it sooner rather than later. The problems will only get worse as time goes on as all of those connections start corroding.

-Spartan

[FLG]

Make sure the computer is good. It could be the sending unit for the fuel pump, could be the fuel pump relay. The "check Engine" light could be computer related or faulty/loose wiring or connectors.

[Spartan]

Speaking of fuel, check the fuel filter. It is an often overlooked service item. Also you can run it by Auto Zone and they will read codes for free.

-Spartan

[Redfallon]

Thanx for the things to look for guys! Today's the day I really get to get dirty, going to leave work at noon and dig in ;)

Spartan: I agree with you on the computer, I think we're going to try that and an ignition module first....If she could afford a different car I know she would :( The computer is passenger side kick panel on GM's, so I am figuring it's flood damage also. Going to try to disconnect the Torque converter control solenoid first, as it can cause stalling, but that's only on slowdown after cruising, and I don't think it'll help, but hey to unplug a connector and take it for a quick drive, I figure it's worth it to check. Also I've tried two different code reader's and am getting nothing, no code...got a third one on the way this morning from a shop...Normally this would make me think for sure it's computer, but I wonder also if whatever moron replaced the engine hooked everything up right :(

Nothing like cleaning up someone else's mess! Well thanx again guys, hoping we can get this straight today!

Shop she took it to already replaced fuel pump and filter to the tune of $300, which kind of p***es me off because a) it was running rich and b) they didn't check the fuel pressure before replacing them....I didn't think it was either of those parts....

[glc]

I think FLG may have touched upon the problem - my suggestion is replace the oil pressure sender. GM cars will shut the fuel pump down when the oil pressure drops below a certain value - or the computer THINKS it has. The oil light flicking on and off was my clue here.

[Redfallon]

Well time for a little bit of an update/vent here :) Tore the thing apart, computer had two bent pins on the middle cable, hence the cable was slightly loose, re-hooked it, then thanx to my friends $2500 snap-on scanner, found the problem to be the IAC (idle air control) valve. Replaced, ran good after a couple minutes of "reset time". Then began running hot. 230F stop/go traffic driving for around 30min. Thought "maybe t-stat just stuck closed" even though I've *never* had one stick closed. Little housing on side of block, two bolts, no problems ehh? Removed housing, no t-stat...turns out 1994 and up they moved it to the water pump housing. Spend next three to four hours trying to get to the t-stat by removing/loosening various brackets, parts, etc. Little metal "down tube" that holds t-stat is wedged between engine pan, tranny pan. Decided, Fri night around midnight, maybe tomorrow morning would reveal more. Sat still couldn't get the pipe completely out, got it down enough to find it has *no* t-stat in it. Realizing water pump has 75,000 on it, figured a water pump/t-stat would be in order for her closer to winter. Couldn't bring myself to drop tranny slightly to removed the wedged pipe, I've never torn a car apart and had to tuck my tail in shame and put it back together without fixing why I took it apart in the first place. But I figured with no t-stat, and still overheating, my time was better spend tracking down the real problem for now. Got the thing buttoned up, but housing where I thought t-stat was leaked. . . Removed again, cleaned up, put back on and then it was time for the Fireman's festival sat night. Sunday morning, puddle of antifreeze still on drive, decided Sunday was a day of rest so I let it go till yesterday. Last night replaced housing again (no leaks this time!!) and determined overheat caused by fan control relay. Easy fix there, got a new one, all ready to drop the car off last night when, *BAM* flat tire. After waiting 45 minutes for someone to come get me to take me to get my car (as this POS didn't have a tire iron or jack in it!) I finally get the donut inflated (0 psi out of the trunk) and get it on, limping the car back to my place. Sigh. . . Oil pressure light still flicking on hit and miss while idling. I am thinking bearings in pump are going. If that's the case, next week or two I am thinking drop the pan, replace pump and/or sender, t-stat (as that should free the pipe) and probably a water pump and since ya have to take the exhaust manifold off to get to the water pump, might replace cat-back exhaust! Gotta love it! Thanx for all your help above guys :)

[glc]

Sounds like it's time to find a replacement car. The Quad 4 was not one of GM's better efforts - it had a lot of issues even when it wasn't messed up. My sister has been driving Pontiacs for over 20 years now and her 92 Grand Am with a Quad 4 was the worst of the bunch. She traded it in right after her extended warranty expired - it was just about to eat its third timing chain, it sounded like a diesel when it was idling. She's been sticking with V6's since and they have been a lot more reliable. Even her two Iron Duke (old pushrod 2.5 liter 4 banger) Fieros were more reliable.

[Redfallon]

Yeah the farther I go the more I realize that. Got a buddy with an old 89 GA with the same quad4, he's never had a problem. This thing, though, just one headache after another.

[Spartan]

Unfortunatly alot of modern cars are like that. I used to (semi) joke with my buddy that when it was time to tune up his 94 Trans Am he would be better off selling it. Those things are murder to work on. It sounds like you are on track though, I didn't even think of the IAC motor but it is a common problem.

-Spartan

[Redfallon]

ARGH! I think G and spartan are right. The tire had a busted valve stem (christ, some luck to have a busted valve stem!) anyway, got the tire put on, started the car up, stalled (maybe just cold, who knows) backed up, took off down the road, clatter clatter clatter at low-mid RPM. I am thinking a cam bearing or even worse, getting ready to throw a rod. I think it's time i cut bait and walk away from this one! Thanks again for all the input fellas!

[glc]

Clatter clatter clatter on a Quad 4 is very likely the cam chain. Time to bail out.

[Redfallon]

Wow G you know everything about anything :) I did a compression test, 1-2-3 all 170psi, number 4, 155psi, so that's not looking to good for the head gasket. The clatter sound seems to be coming from the number 4 cylinder also, with my trusty auto stethoscope I can tell it's worse on that side of the engine (drivers) but can't tell if it's in the pan (rod?) or somewhere else, the sound is unfortunately quite noticable. Hopefully she's getting a new car soon enough, now this thing has become my mission. Without sinking TOO much more dough into it (the car was given to this person free, so far we've got about $500 in it), I'd like to get it running as the thing is still giving me fits. The head gasket I can tackle, having a shop nearby to check/machine the head if needed. You referring to the timing chain g? I assume, the chain is kinda noisy, but no more so than the one on my friends 89 grandam, listening with the steth that is. I always thought if a chain goes your not in as much danger of a valve crashing or what have you as with a belt. Am I incorrect on that? And if I am, and I end up putting a head gasket in, I can do the chain at the same time. Thanks again for your time G.

[Spartan]

If the the timing chain has slipped a few teeth then you probably would be having some backfiring problems. My wife had a Grand Am (pre Quad 4 days) that had the timing chain slip and resulted in a bent valve. If you are going in to do a head gasket you might want to at least eyeball those. Chain or belt is equal danger in my book and yeah if you have it that far apart you might as well do the chain. The danger is when a chain or belt breaks the cam stops turning and you may have a valve open as the piston comes up to TDC. Most times the spring pressure on the valve will reseat it, but it may not be fast enough and the odds are that one lifter will still be on a cam lobe. OHC engines may be a little different and I don't know what the piston to valve clearance is on those. Sounds like a lot of dirty work though......I wish you well.

-Spartan