doesn't want to run (1990 3.1 MPFI)

[3100 MPFI]

Okay. I have replaced just about everything I can think of.

My 1990 Grand Prix STE with the 3.1 MPFI (non turbo) has a running problem. The starter had BROKEN, but even before this, I was having the problem. I finally replaced the starter (the car has been sitting for almost 3 months), and I am having a problem where when the car warms up, it wants to stall.

I started the car, and it had the usual hard start problem that all of these cars get when they sit, but after I got it stable, it ran fine. After about 10 minutes (I am guessing when it finally warmed up to the point of going into closed loop), it stuttered and died. Now, just to start it, I have to give it gas, and if I put it in gear, it will bog down to the point of dying (even with my foot on the gas).

I tried replacing the ECM, and it does the same thing. All the sensors are new, and it also has new plugs, wires, DIS, and coils. New TPS, IAC, and FPR.

The only thing I can think of is something wrong with the MAP. When the FPR went out, it put a LOT of fuel into the vacuum line, and blew out my MAP. I put another one on there but am thinking it might have had some fuel still in there.

Is there anything I can check to find out why this car is doing this? I need the car for a trip I am taking in about 3 weeks.

[Superdave]

sounds like it could infact be the MAP, replace the vacuum line to it and grab a MAP from the nearest salvage yard.

[3100 MPFI]

Does the 1995 3.4 DOHC have an MAP that I can just take it off of my old car, and throw it on there for now?

[Superdave]

If it looks the same it should work.. GM dosen't change MAP sensors much...

[3100 MPFI]

Where would the MAP be on the 3.4 DOHC? Just looking at the 3.4, I can't find it.

[TazMan]

DIsconnect the electrical connector to it and see what happens. The map sensor was bad on my 3.1mpfi and the car didn't want to go either. I unplugged the electrical connector to get it home, and was drivinging around for a week without it, with no problems. Acceleration was just a little choppy. Not that you should run around with no map sensor, but if it is bad, I guess as a test, the car should drive without it. You can jump terminals A&B on the diagnostic connector and check for codes also. Is the SES light on?

[3100 MPFI]

The SES light works (damn air temp sensor), but no codes as to why it dies. As soon as it hits closed loop, it dies.

I will try disconnecting it and see what happens. If nothing else, I will replace the map. There a several 3.1's at the local yard. I just messed up a new map sensor, and don't want to get a new one yet until I know for a fact that is the problem.

i think I might have a couple of sensors in storage as well. I will have to look into that.

[GPXSS]

no MAP on a 95 3.4 dohc. Wish I had known sooner, i could have sent you one with the rods.

[3100 MPFI]

I think I have a couple in storage. I just have to get over there and get them.

If not, I will just hit the local boneyard.

The rods got here today. I did not have a chance to get to the bank to deposit my check today, so I will paypal you tomorrow.