Intermediate stalling on '89 Maxima: Possible Fix update
02-28-2003, 09:20 AM
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Intermediate stalling on '89 Maxima: Possible Fix update
A few months back, I posted about having intermediate stalling problems with my '89 Maxima SE. The symptoms were:
* car would stall without any warning, whether idling or whether the car was in motion,
* the only code pulled off from the ECM was a defective MAF sensor.
The fixes that I initially tried was replacing my 5-pin MAF sensor with a $500 remanufactured one (didn't work), checking the wire harness out, and replacing the oxygen sensor (which didn't work but did open another can of worms ... long story). None of these fixes worked, and I still occasionally got a defective MAF sensor error after the car stalls. This problem persisted for about 4 months after I had tuned the car up and cleaned out the MAF sensor by removing it from the car to clean.
POSSIBLE FIX: What I ended up doing is taking my MAF sensor out from the car again, and this time, I wanted to check the electronics inside the MAF sensor for any signs of an electrical short or some other anomaly. With an Exacto knife, I made a cut into the silicon material that held the square plastic lid cover over the electronics, and removed the cover. Inside, I can see a copper shield which was held down by a screw. I removed the screw, and carefully bent the shield aside, exposing the electronics. Without knowing the exact specs as to what the readings should be inside, the only thing I could do was a visual check, and everything looked okay. I also noticed, however, that the five pins on the MAF sensor to which I connect my plug to on the exterior are simply soldered onto the board on one end. I took a soldering iron, softened the existing solder that held the pins to the board, and applied more solder to those four points. (The fifth pin on on the MAF sensor mysteriously doesn't connect to anything, and there was no indication on the PCB board inside the MAF sensor that the pin was supposed to connect to it). I put everything back together, applied a fresh line of silicon material around the black lid, and reinstalled it into the car.
Strangely enough, I haven't had a stall since that! It's been approximately 3 months now and 5k miles since that soldering job, and I think my problem might have been solved by resoldering those 4 pins, even though they looked fine. What I suspect went wrong? When I was cleaning the MAF sensor, all the plugging / unplugging of the connector to the MAF, coupled with cleaning the pins on the MAF sensor with cotton swabs, and the natural vibration levels that the MAF sensor sees when the car engine is running, might have caused the soldered pin connections to have come loose off from the electronic board. It wasn't loose enough to the point where my car would be stalling all the time, but it was just loose enough that if the conditions were just right, the pin may momentarily lose contact with the electronic board, breaking the circuit, and thus, car stalls and car ECM picks up a defective MAF sensor code.
Why did the remanufactured MAF sensor not work in the car? I really don't know. It was the correct MAF sensor that went into the car, it had 5-pins like the one in my car, and it was installed correctly. Either that remanufactured part wasn't working when I got it, or my car just doesn't like aftermarket parts for its electronics, which has been the case with my car and Bosch oxygen sensors.
In any case, my car's been running fine as expected for the past 3 months now, and the MAF sensor code has not returned. I hope that this post may help out some of you who has had very similar symptoms to my '89, and perhaps save you a few bucks from having to replace your MAF sensor entirely.
And again, thank you to all who had originally helped me out with my problem when I posted it a few months back.
Regards,
- Alan
- '89 Maxima SE, 245K miles
* car would stall without any warning, whether idling or whether the car was in motion,
* the only code pulled off from the ECM was a defective MAF sensor.
The fixes that I initially tried was replacing my 5-pin MAF sensor with a $500 remanufactured one (didn't work), checking the wire harness out, and replacing the oxygen sensor (which didn't work but did open another can of worms ... long story). None of these fixes worked, and I still occasionally got a defective MAF sensor error after the car stalls. This problem persisted for about 4 months after I had tuned the car up and cleaned out the MAF sensor by removing it from the car to clean.
POSSIBLE FIX: What I ended up doing is taking my MAF sensor out from the car again, and this time, I wanted to check the electronics inside the MAF sensor for any signs of an electrical short or some other anomaly. With an Exacto knife, I made a cut into the silicon material that held the square plastic lid cover over the electronics, and removed the cover. Inside, I can see a copper shield which was held down by a screw. I removed the screw, and carefully bent the shield aside, exposing the electronics. Without knowing the exact specs as to what the readings should be inside, the only thing I could do was a visual check, and everything looked okay. I also noticed, however, that the five pins on the MAF sensor to which I connect my plug to on the exterior are simply soldered onto the board on one end. I took a soldering iron, softened the existing solder that held the pins to the board, and applied more solder to those four points. (The fifth pin on on the MAF sensor mysteriously doesn't connect to anything, and there was no indication on the PCB board inside the MAF sensor that the pin was supposed to connect to it). I put everything back together, applied a fresh line of silicon material around the black lid, and reinstalled it into the car.
Strangely enough, I haven't had a stall since that! It's been approximately 3 months now and 5k miles since that soldering job, and I think my problem might have been solved by resoldering those 4 pins, even though they looked fine. What I suspect went wrong? When I was cleaning the MAF sensor, all the plugging / unplugging of the connector to the MAF, coupled with cleaning the pins on the MAF sensor with cotton swabs, and the natural vibration levels that the MAF sensor sees when the car engine is running, might have caused the soldered pin connections to have come loose off from the electronic board. It wasn't loose enough to the point where my car would be stalling all the time, but it was just loose enough that if the conditions were just right, the pin may momentarily lose contact with the electronic board, breaking the circuit, and thus, car stalls and car ECM picks up a defective MAF sensor code.
Why did the remanufactured MAF sensor not work in the car? I really don't know. It was the correct MAF sensor that went into the car, it had 5-pins like the one in my car, and it was installed correctly. Either that remanufactured part wasn't working when I got it, or my car just doesn't like aftermarket parts for its electronics, which has been the case with my car and Bosch oxygen sensors.
In any case, my car's been running fine as expected for the past 3 months now, and the MAF sensor code has not returned. I hope that this post may help out some of you who has had very similar symptoms to my '89, and perhaps save you a few bucks from having to replace your MAF sensor entirely.
And again, thank you to all who had originally helped me out with my problem when I posted it a few months back.
Regards,
- Alan
- '89 Maxima SE, 245K miles
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