I was driving home when suddenly the car died. I got it restarted after holding my foot to the floor but the car won't idle at all. Tons of black smoke came out of the exhaust. Had to tow it 34 miles back to my house.

I even let the car sit for a while and it does the same thing. Have to hold my foot to the floor to get it to fire and as soon as I let off it dies again ....

Any suggestions? You are all very helpful and knowledgeable and have helped me before. The car is approaching 155.000 miles.

Thank you!
Rich
Dubble6s

Possibility of your MAF sensor taking a dump. It is located on the top of the throttle body. Disconnect the electrical connector and then fire it up and see what it does. Initial idle may be a little erratic until the engine warms up. The PCM will recognize the MAF signal missing and use pre-programmed MAF/VAF tables. The fuel injection system is in full fuel rich trim based on the black smoke.

Possibility of your MAF sensor taking a dump. It is located on the top of the throttle body. Disconnect the electrical connector and then fire it up and see what it does. Initial idle may be a little erratic until the engine warms up. The PCM will recognize the MAF signal missing and use pre-programmed MAF/VAF tables. The fuel injection system is in full fuel rich trim based on the black smoke.

Thanks, I will give that a try. Based upon the cars in your signature, I take it you have experienced this before?

This has been such a good car and I want to drive it for as long as it will hold up .... I used to be a mechanic but that was back when there was just a motor, transmission and wheels. The rest was optional. :grinyes:

Rich
Dubble6s

Thanks, I will give that a try. Based upon the cars in your signature, I take it you have experienced this before?

This has been such a good car and I want to drive it for as long as it will hold up .... I used to be a mechanic but that was back when there was just a motor, transmission and wheels. The rest was optional. :grinyes:

Rich
Dubble6s

Hopefully your problem is the MAF sensor. Easy to change out. Just two Torx safety screws hold it onto the throttle body.

Oh yes, I've had MAF sensor failures in at least two of them. The '97 GTP and the '99 Regal LS. Similar symptoms. No or poor idle, hard starting, black smoke out the exhaust, poor acceleration and a bad cutoff like misfire around 4000 rpms. Bad part no SES light and no odb-ii DTC error codes.

Plus the part is expensive. Around $220 GM List new. Around $120 for for a remanufactured. On one of them I lucked out and got a MAF sensor at the salvage yard for $40.00.

The picture shows I have to buy the whole assembly. I just can't buy the sensor?

http://img127.imagevenue.com/loc593/th_70248_maf_593lo.jpg

http://www.partsamerica.com/product_images//img/a1c/rep-selectmaf.jpg

If that's the case I can see why it is so expensive .....

The part depiction from your source is deceptive. You will not get a complete throttle body which costs alot more. All you will be getting is the MAF sensor itself. It is expensive because it is an electrical/electronic device. See pic below.

http://i5.photobucket.com/albums/y186/lizzywiz/maf.jpg

Well, I tried what you said and as soon as I unplugged it, the car started right up. It ran for 5 minutes before I had to shut the key off. I plugged the MAF sensor back in and started the car. The car dies within 5 seconds.

My brother, who was a mechanic a lot longer than I was, told me it might be a fuel pump issue. Clearly your solution seems to be the one that will fix my vehicle.

I am going to change it and will report back what happened.

Thank you so much!
Rich
Dubble6s

You are welcome and I am quite sure you found a bad MAF sensor.

BTW - You can run the car without the MAF connected for awhile until you get the new one. I did for over 1 week until the part came in.

You may get less fuel economy and the initial idle at startup will be erratic - fluctuate until the engine warms up.

Good luck and let us know how it turns out.

I am happy to report that the MAF sensor has fixed the problem. The car runs just like it did before.

Thanks to everyone for their help!
Rich
Dubble6s

I am having a similar problem, but mine has gotten a lot deeper..

I am not getting any smoke, and I am getting the 0102 code(low reading).

I've had this code for about a year now, I've been working on fixing it for about 4 months since it has now started causing driveability problems. Starts rough, then after a few surges, the idle evens out. Then at idle, after driving, it stalls out(which is terrible in the tunnels and in the interstate traffic)

The first thing I did was replace the sensor(reman), it ran good for about a few hours. Then the light came back on.

Then after a lot of trial and error, mostly error, I've replaced the upper intake plenum gasket, all the vacuum lines and connectors, the throttle body, the IAC, MAP, EVAP solenoid, plugs, wires, fuel filter, IAT, PCV, the connector to the MAF, and tested the EGR(which is operating good).

I then broke down and bought a scanning software (i wont mention the name because I'm not sure if you can do that here). You basically plug your laptop into your car's OBDII connector and you can see the live data, clear the codes, tests, etc.. It shows the MAF as being inoperative most of the time. I set the software to display an oscilloscope reading of the the MAF, throttle position, and MAP. When the everything is running correctly and no code is present, all three of those sensors display a similar scope reading. When the code is thrown, the MAF reading falls out to near zero and doesn't respond to the pedal.

I also notice that when backprobing the MAF input wire the goes to the ECM(at the mass) it has a voltage fluctuating around 2.7V when there is no code. When the code is present, the voltage there is 5V. The other wires:the voltage from the positive wire is constant in both cases and the ground wire providing a constant ground.

I replaced the sensor again, and it ran good this time for about 2 days. Now it's doing the same thing. Then oddly enough, with the laptop hooked up, the other day i was getting no response from the MAF reading and I got upset and pounded on it, and it started kicking out readings again. Now i notice when i tap on the sensor it is responding.

Being that I am on my third MAF replacement and contemplating getting one from the dealer, which is going to cost much more, I am wondering if there is something that the computer is doing to damage them? I have actually been buying the one pictured in the link earlier in this thread.

I've even disconnected the ECM and checked all the pins.

I dont want to replace the ECM if its not necessary, but I cant think of any other routes to diagnose. Can anyone think of anything I could have overlooked?

!!ANY!! insight would be more than appreciated

also, my car is 97 pontiac grand prix 3800, non-supercharged

I am having a similar problem, but mine has gotten a lot deeper..

I am not getting any smoke, and I am getting the 0102 code(low reading).

I've had this code for about a year now, I've been working on fixing it for about 4 months since it has now started causing driveability problems. Starts rough, then after a few surges, the idle evens out. Then at idle, after driving, it stalls out(which is terrible in the tunnels and in the interstate traffic)

The first thing I did was replace the sensor(reman), it ran good for about a few hours. Then the light came back on.

Then after a lot of trial and error, mostly error, I've replaced the upper intake plenum gasket, all the vacuum lines and connectors, the throttle body, the IAC, MAP, EVAP solenoid, plugs, wires, fuel filter, IAT, PCV, the connector to the MAF, and tested the EGR(which is operating good).

I then broke down and bought a scanning software (i wont mention the name because I'm not sure if you can do that here). You basically plug your laptop into your car's OBDII connector and you can see the live data, clear the codes, tests, etc.. It shows the MAF as being inoperative most of the time. I set the software to display an oscilloscope reading of the the MAF, throttle position, and MAP. When the everything is running correctly and no code is present, all three of those sensors display a similar scope reading. When the code is thrown, the MAF reading falls out to near zero and doesn't respond to the pedal.

I also notice that when backprobing the MAF input wire the goes to the ECM(at the mass) it has a voltage fluctuating around 2.7V when there is no code. When the code is present, the voltage there is 5V. The other wires:the voltage from the positive wire is constant in both cases and the ground wire providing a constant ground.

I replaced the sensor again, and it ran good this time for about 2 days. Now it's doing the same thing. Then oddly enough, with the laptop hooked up, the other day i was getting no response from the MAF reading and I got upset and pounded on it, and it started kicking out readings again. Now i notice when i tap on the sensor it is responding.

Being that I am on my third MAF replacement and contemplating getting one from the dealer, which is going to cost much more, I am wondering if there is something that the computer is doing to damage them? I have actually been buying the one pictured in the link earlier in this thread.

I've even disconnected the ECM and checked all the pins.

I dont want to replace the ECM if its not necessary, but I cant think of any other routes to diagnose. Can anyone think of anything I could have overlooked?

!!ANY!! insight would be more than appreciated

also, my car is 97 pontiac grand prix 3800, non-supercharged

Replies posted at Pontiac Grand Prix forum.

BTW - I'm the same Bnaylor there too.