Symptoms of a Failing MAF Sensor
08-01-2010, 12:45 PM
#1
Three Wheelin'
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Symptoms of a Failing MAF Sensor
After diagnosing a failed MAF sensor on my 89 GT, I thought I'd put this out there for search fodder in case someone else has the same symptoms. This entire progression took place over about a month while driving the car almost daily.
The first symptom began about a month before complete failure with the car stalling on occasion after full release of the gas pedal when stopping. Usually it didn't shut down, but it would always dip down too low in the rpm range before revving back up to normal idle.
The next symptom was very poor performance just after cranking it. It only happened a couple of times but I was barely able to keep it running after starting it. Both times, I shut it down and it ran fine after immediately cranking it again.
Next came the two times that it would not restart after shut down when hot. Both times I assumed relay, relay, relay and after swapping a few relays, it started back up and ran fine. The third time this happened, there was no restarting it. Luckily I was in my driveway. Even when she's bad, she's good.
It would fire and run for a second or two and then stall. If I worked the pedal, I could keep it going but running very rough.
After swapping a few other items, I tried the MAF sensor and she fired right up and is running better than it has since the symptoms began. It really helps to have at least one other running 928 of similar vintage when diagnosing problems. I recommend they be bought in pairs.
The first symptom began about a month before complete failure with the car stalling on occasion after full release of the gas pedal when stopping. Usually it didn't shut down, but it would always dip down too low in the rpm range before revving back up to normal idle.
The next symptom was very poor performance just after cranking it. It only happened a couple of times but I was barely able to keep it running after starting it. Both times, I shut it down and it ran fine after immediately cranking it again.
Next came the two times that it would not restart after shut down when hot. Both times I assumed relay, relay, relay and after swapping a few relays, it started back up and ran fine. The third time this happened, there was no restarting it. Luckily I was in my driveway. Even when she's bad, she's good.
It would fire and run for a second or two and then stall. If I worked the pedal, I could keep it going but running very rough.After swapping a few other items, I tried the MAF sensor and she fired right up and is running better than it has since the symptoms began. It really helps to have at least one other running 928 of similar vintage when diagnosing problems. I recommend they be bought in pairs.
08-03-2010, 12:27 PM
#6
Drifting
Did you have for MAF rebuilt or replaced?
I just had mine rebuilt and plan on installing it tonight. Kevin at injector labs confirmed is was going out, but I wasn't sure how far out of specs it was.
How long were you have you been symptom free?
I just had mine rebuilt and plan on installing it tonight. Kevin at injector labs confirmed is was going out, but I wasn't sure how far out of specs it was.
How long were you have you been symptom free?
08-03-2010, 12:34 PM
#7
