2001 GP runs only when MAF sensor is unplugged - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 11-22-2016, 03:23 PM   #1
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Default 2001 GP runs only when MAF sensor is unplugged

Hi all. Symptoms:

A week ago the engine/car would abruptly stall after warmup leaving us stranded.
Got car home. Started it up idling the next day and within a few minutes it stalled. Attempting immediate restart would not work. Had to let car rest for an hour or so and then it would start and do the same stall again.

I then unplugged the MAF sensor and the car would remain running just fine with a very slight fluctuation on the RPMS negligible. At least it runs and won't stall or shut down at all and starts fine the next attempt too.

Googling I found the stalling when warm is or could be a CRANKSHAFT SENSOR GOING BAD. When to NAPA USED OBDII code reader, cleared the codes with MAF P0102 error. But that is because it was unplugged when I ran the test. Car will no longer even cold start now with it in.

No $$ to take car to the guys who has the big test machine $$ which tells you the exact problem. MAF problem Crankshaft sensor problem? dunno. Saw MAF sensor on ebay for $20 maybe I could try that? Any help appreciated.
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Old 11-22-2016, 04:35 PM   #2
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If the car runs better when you unplug the MAF, the problem is the MAF. Pull it out and examine the fine wire elements. If one is broken you need a new MAF. If they are dirty you might be able to get away with cleaning them. If you try to clean them, do not use anything other than a spray for cleaning MAF'*. CRC makes a good one. Do not use carb cleaner or anything other than a cleaner specifically for MAF'*, and don't use anything that actually contacts the wires (like a Q tip).


Clean MAF element wires will be a nice shiny silver color.


Now the bad news. A decent MAF will run you at least $100. A MAF off Ebay for $20 is garbage. Hopefully a good cleaning will fix the issue.

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Old 11-22-2016, 05:00 PM   #3
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OK thanks I'll get some CRC MAF cleaner tomorrow. After letting the car cool for a few hours I actually was able to start the car idled ruff at low rpm smoothly at higher and after 1 minute the car shut off/stalled. I'll try the cleaner and get back and take photos of it as well maybe that will help thanks SOOO much sir.
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Old 11-24-2016, 09:52 PM   #4
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No pics but I did clean the sensor with CRC with no luck. The car runs with MAF unplugged doesn't run with it in. Thanks again I may get one from a junkyard as they said $30 as I can't dump $100 for that sensor into this car. Thanks again
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Old 11-25-2016, 12:47 AM   #5
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Quote:
Originally Posted by hoarybat View Post
No pics but I did clean the sensor with CRC with no luck. The car runs with MAF unplugged doesn't run with it in. Thanks again I may get one from a junkyard as they said $30 as I can't dump $100 for that sensor into this car. Thanks again
The reason 2kg4u warned you against the cheap Ebay sensors because they are manufactured with cheap resistors that will throw your fuel trims way out of whack. I speak from experience on this. I found an OEM(Hitachi) MAF on Ebay from a junkyard for 25 bucks and it worked just fine.
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Old 11-26-2016, 03:47 AM   #6
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Default Vacuum leak?

Most of the vehicles I come across like this, if the MAF sensor is not the problem, tend to have a vacuum leak. The MAF sensor tells the computer how much are is being used, so a vacuum leak will be unmetered and cause stalling and rough running, especially at low rpm. Try revving the engine and seeing if it runs better at high rpm. unplugging the MAF means the computer will have to figure that out on its own and vacuum leaks are not as noticeable anymore. Always a good place to start with symptoms like that. Try dumping some water around the engine bay and listen for the sound of the engine sucking it up. visually inspect any accessible vacuum lines for cracks and that they haven't popped off. You could pump smoke into a line and look for it coming back out somewhere as well. A cigar is sometimes a usable alternative to a real smoke machine.

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Old 12-11-2016, 08:59 PM   #7
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Hi all sorry it took so long on feedback. got an MAF from junkyard plugged it in car did not stall when up to temperature. Check engine did not clear so I disconnected battery to clear it and it has not come back on. Idle is still a little high when car is first started does better after a few minutes of running. I took out the ICV and it was all coated with black with much carbon. Didn't look good at all of course after 16 years. Don't know why it is not throwing a code. Either way car is running and hopefully will get us to springtime. Thanks....
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Old 12-30-2016, 01:23 PM   #8
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When I put the replacement Idle Control valve it gave me a service engine and would not clear after I disconnected battery to do so. Car is running smoothly tho and grandfathered for inspection so no biggie.....
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