Engine Stalls Upon Acceleration

[loiselle]

1992 Oldsmobile Cutlass Supreme 3.1 V6/Auto, 89k miles

I know this is probably off subject and I will get my butt kicked for it, but I need to ask a mechanic's advice. My mother-in-law gave me a nice 1992 Olds Cutlass Supreme about 7 months ago and it ran great. Suddenly I am having problems:

The problem is intermittent (off and on although more on lately). Sometimes it is hard to start. The real problem comes when you try to accelerate. It stalls and cuts out. Often you can feather the gas pedal and gradually accelerate. It misses sometimes and cuts out on acceleration sometimes. We have already replaced the fuel pump, fuel filter, map senor, and IAC sensor. We also cleaned out the throttle body.

With all of this effort, nothing really has changed ... in fact it may be worse. You can unplug the IAC sensor and/or IAT sensor and it does not make any difference.

I just went outside and tried it. It start up and idled fine. As soon as I put it gear it stalled. I feathered the accelerator and drove it a mile. If I gave it too much gas it died.

Sheesh. Maybe my shotgun can fix it. Help?!?

Thoughts:

I think the TPS (Throttle Position Sensor) is a potentiometer that tells the ECM that I have stepped on the gas pedal and how much. Then the ECM tells the injectors how much gas to give it. Right? If it is not working properly (like a bad dimmer switch) I probably will get too much or too little gas. It acts like an old car with a carburrtor with a bad accelerator pump.

What say you? Thanks.

[enjenjo]

You can check the TPS with a digital Ohm meter to see if it's working. The service manual will have the resistance values at different throttle settings.

[Crosley.In.AZ]

I see you have replaced many parts.


Have you verified the  new parts are operating within specs?

[wayne petty]

did you change the coolant temp sensor...
that affects fuel mixture more than anything else....

how about the fuel filter.

can you hear the fuel pump spin when you turn on the key?? it should cycle on for 2 seconds when you turn on the key... and stay on while cranking.. but you cannot hear it while cranking...

also....      look around the top of the motor.. see if you see any thin... like 14 gauge ground wires out of the fuel injection harness.   remember  the ecm is grounded  only to the motor... not to the battery directly...

i am almost sure that these may all be grounded to a bellhousing bolt/stud... take that off and wire brush the ring term...  take the stud out and wire brush the bolt.. then reinstall it...  that cures many evils with these systems....

here are some links...
engine componant locations
http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//0900c152/80/06/7e/87//large/0900c15280067e87.gif

this should take you to the drivability section   edit... oops... you have to enter the info but it will get you there.. end edit
http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c15280067e40

and have any codes shown up??

do you know anybody with a gm style scan tool there are a lot of them around...


oh.... and this is a most important chart to have on hand... it is what should be seen on most of the circuits while the engine is running... on many gm cars...

http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images//0900c152/80/06/7e/6a//large/0900c15280067e6a.gif
wayne