Ok here's the problem.. The car starts just fine, then it stalls after 5 seconds. Sometimes if I can get the car running after holding the gas down for like 5 minutes the car then stumbles and pops upon acceleration.. Its a reman 2.8. It ran fine for 6 months then it got steadily worse and now its undriveable. I actually got it to run after replacing the O2 sensor, but after unplugging the batteryto try and fix the volt light staying on (its reading 14 though) it started stalling again. I also am getting a code 44 lean exhaust.

I started threads on this already and searced and read hundreds of archives searching for an answer.

Here's what we can rule out without a doubt:

All of these are either brand new, or recent:

IAC (will try readjusting tomorrow by removing and setting to 1 1/8 th inch
TPS
Air Charge Sensor
Ignition Module (just finished swapping with another)
O2 Sensor
EGR valve and tube
Vacuum leak (checked multiple times)
Coolant temp sensor (gives good reading on winALDL)
MAP sensor (tried spare, problem persisted)
EGR solenoid (tried spare, problem persisted)
oil pump

Here is what has been replaced recently replaced but I would be willing to try:

MSD coil
MSD plug wires
AC delco plugs (replaced with new engine last thanksgiving)
All ignition components are recent
All sensors, switches, and sending units are recent, every single one has been replaced with new
Exhaust is new
Throttle body bored and polished
1.6 rockers
underdrive pulley
drive belt
battery
bat cables

These are original:
Fuel pump
fuel pressure regulator
injectors
cold start injector
alternator
wiring harness
ECM

I am trying to get a fuel pressure gauge right now, I should have it in a few days. Any ideas?

[This message has been edited by connecticutFIERO (edited 10-13-2004).]

Man this is crazy. Looks like you're at your wits end.

If it ran good for 6 months, something has obviously deteriorated. I see you plan on checking fuel pressure and that's what came to my mind. Sounds like a classic symptom of a pump on the way out the door. I had a car I drove for a couple months on a bad pump. It made just enough to keep it running (most of the time). It stumbled, backfired, and everything else you can think of. It basically ran like the computer was going crazy. All that due to low fuel pressure.

Next thing I would check after verifying the pump is supplying the proper pressure: check the injectors or the wiring harness to the injectors. The ground for the injectors may be bad (I don't know if they're grounded individually or use a common ground). If it's weak it could be causing them to fire intermittently. I had this happen on an 89 olds I used to have. The injector wiring harness ground was bad and it would run like crap. It took me forever to figure it out.

Also should note that on that above oldsmobile I had the computer go out. It came on all of a sudden and didn't make it 3 miles. It ran like total garbage for a few minutes and then stopped. I would put the possibility of the computer low on the list though. They don't burn too often.

I would also triple check all the major grounds like the battery to engine, engine to frame.

good luck,
Dave

[This message has been edited by ditch (edited 10-12-2004).]

quote Originally posted by ditch: Man this is crazy. Looks like you're at your wits end. If it ran good for 6 months, something has obviously deteriorated. I see you plan on checking fuel pressure and that's what came to my mind. Sounds like a classic symptom of a pump on the way out the door. I had a car I drove for a couple months on a bad pump. It made just enough to keep it running (most of the time). It stumbled, backfired, and everything else you can think of. It basically ran like the computer was going crazy. All that due to low fuel pressure. Next thing I would check after verifying the pump is supplying the proper pressure: check the injectors or the wiring harness to the injectors. The ground for the injectors may be bad (I don't know if they're grounded individually or use a common ground). If it's weak it could be causing them to fire intermittently. I had this happen on an 89 olds I used to have. The injector wiring harness ground was bad and it would run like crap. It took me forever to figure it out. Also should note that on that above oldsmobile I had the computer go out. It came on all of a sudden and didn't make it 3 miles. It ran like total garbage for a few minutes and then stopped. I would put the possibility of the computer low on the list though. They don't burn too often. I would also triple check all the major grounds like the battery to engine, engine to frame. good luck, Dave

Yeah I really am going crazy with this problem. This is the first time i haven't been able to fix my own Fiero. I should mention that I added two grounds so I know the engine has good ground. Where would the injector ground be?

The pump is certainly a possibility, but why does it start fine and then run, but won't idle? Its crazy.

usually the injectors are grounded by the computer.

the injectors are fed current, while the ground wire goes the computer and a transistor turns
them on and off.

quote Originally posted by CertifiedMechanic: usually the injectors are grounded by the computer. the injectors are fed current, while the ground wire goes the computer and a transistor turns them on and off.

Thanks, I don't think thats the problem then.

Oil pressure switch or relay?

I had what sounds like the same problem. I assumed I had good fuel pressure because I could see fuel coming out in a nice cone out of the TBI. First off, dont assume anything, TEST it. While cranking I had good fuel flow. I went ahead and replaced my fuel filter. While it was removed I jumped pin G on the ALCL to 12v. This makes the fuel pump run constant. I had good flow so I hooked up the filter and assumed my pump was working fine. After hours and hours of testing every thing in the book (except the check fuel pressure test, I had good flow right). I broke down and bought a fuel pressure tester. I had only about 1 PSI of fuel. I dropped the tank and found a split hose in the tank comming off the pump. I went ahead and replaced the whole thing after all it is 20 years old.

Bonzo

quote Originally posted by CertifiedMechanic: usually the injectors are grounded by the computer. the injectors are fed current, while the ground wire goes the computer and a transistor turns them on and off.

The problem I had was that the ground wires from the injector wire harness back to the computer had a short somewhere. The wiring was a bit deterioriated causing a poor connection.

quote Originally posted by connecticutFIERO: The pump is certainly a possibility, but why does it start fine and then run, but won't idle? Its crazy. .

When you first turn the key the fuel pump charges up the system building pressure. After you start the car pressure almost always drops a bit from the starting pressure because the pump is now running constantly and having to circulate the fuel. You might be making just enough pressure before startup, but when it starts that drop in pressure is all it takes to cause it to want to stall out.

[This message has been edited by ditch (edited 10-13-2004).]

I noticed that you said your throttle body was bored, is this a Darryl Morse one or did someone else do it for you? The reason I am asking is that if someone else made it for you, they might have not made a new matching butterfly for it, this would cause a big air leak. Here's another hint for you, don't connect the IAC to power when it is out or it can shoot the pintle out and your have a hard time finding it again. If you want to adjust it, just press the pintle in by hand, it will show some resistance but will go down eventually.

quote Originally posted by avengador1: I noticed that you said your throttle body was bored, is this a Darryl Morse one or did someone else do it for you? The reason I am asking is that if someone else made it for you, they might have not made a new matching butterfly for it, this would cause a big air leak. Here's another hint for you, don't connect the IAC to power when it is out or it can shoot the pintle out and your have a hard time finding it again. If you want to adjust it, just press the pintle in by hand, it will show some resistance but will go down eventually.

Yeah its Darrel TB. I'm going to wait for my fuel pressure gauge. I did replace fuel filter too, I didn't mention that.

i'm having a similar problem. car starts fine, runs 10-30 seconds, coughs, dies. if i let it sit for a bit it starts right up again, same pattern.

i noticed yesterday that my fuel filter is full of brown trash. i havent made it to the parts store yet, but i'm going to put in a new filter, and may drop the tank to replace the "sock" on the pump, too.

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'84 2m4 se, a work in progress http://www.mtsu.edu/~mkr2c/fiero.htm

[This message has been edited by lurker (edited 10-13-2004).]

quote Originally posted by lurker: i noticed yesterday that my fuel filter is full of brown trash. i havent made it to the parts store yet, but i'm going to put in a new filter, and may drop the tank to replace the "sock" on the pump, too.

brown trash is most likely rust particals. I have had many issues with a contaminated fuelsystem. The metal lines will rust inside, the fueltank appeared really clean inside though. You really need to change the fuelfilter every 1 - 2 years now or your injectors will will be clogged with the trash (mine were full of it and they needed cleaning and rebuild).

My "old" fuelpump quit after 10 minutes of driving and I got a new fuelpump. It didn't ran well (if at all) and it took a month of testing and replacing parts and I finally got a pressure gauge too and it showed someone sent the wrong pump, the new one puts out a healthy 38psi (V6) and the engine runs great. A fuelpressure gauge will tell a lot.

UPDATE:

I did test the fuel pressure and got 40 idle and WOT. So I am getting fuel.

I tried replaced the IGN module. No dice.

I replaced the coil. No dice.

No I am not buying new parts and throwing money at the car, I have lots of good parts built up because of two engine replacements.

Does the fuel pressure change with engine vacuum? The pressure should be highest with engine off, and should drop with engine running, and should vary as the throttle is blipped.

JazzMan

quote Originally posted by JazzMan: Does the fuel pressure change with engine vacuum? The pressure should be highest with engine off, and should drop with engine running, and should vary as the throttle is blipped. JazzMan

No it was low at 10 psi until I started the car then it was 40 psi until I shut it off or it stalled. WHy would it be highest with engine off? IF it starts and runs doesn' that mean the pump is working.

bump

check your pm connectfiero...