Short version: I suspect my MAF plug isn't making good contact. How can I either add strength to the contacts, clean them real good or maybe put something in them to help with electrical flow?
Long version: That rich fuel trim problem I've been dealing with is still happening, but I think I've finally found the common denominator: It seems like every time I mess with the MAF plug the fuel trim readings go back to normal. Then after a while they slide rich again. I observed this twice today. Long term fuel trims were -20% this morning, and short terms were bouncing around 0. Removed MAF and cleaned it and immediately on next startup the short term trims bounced around +20% until the long term settled back to -1.6%, then short term settled around 0.
Then tonight after a long drive the long terms were back to -10% with short terms around 0. Stopped the car, unplugged and re-plugged the MAF a few times and voila, short terms shot up to 8-10% until long term dropped to -3% and short term around 0.
This is the only documented data I have so far, but all the other times I've managed to get the long term trims to settle down I'm 99% sure I did something with the MAF beforehand, either unplugging it completely or just jiggling it around.
And yes, I already replaced the MAF sensor a while back in hopes of solving the very same issue. In my service notes I wrote that replacing the MAF seemed to have solved the rich reading. But it just kept coming back. Common denominator in the replacement process? Unplugging it.
I don't think it's the O2 sensors. I highly doubt that both of them would fail in perfect sync to result in identical rich readings on both cylinder banks. And when they do go back to acceptable readings, they're off by about 1.5% which seems far more expected for old sensors. Voltage readings from both look totally fine.
Anyway, what can I try short of cutting the MAF plug off and soldering on a new one?
Long version: That rich fuel trim problem I've been dealing with is still happening, but I think I've finally found the common denominator: It seems like every time I mess with the MAF plug the fuel trim readings go back to normal. Then after a while they slide rich again. I observed this twice today. Long term fuel trims were -20% this morning, and short terms were bouncing around 0. Removed MAF and cleaned it and immediately on next startup the short term trims bounced around +20% until the long term settled back to -1.6%, then short term settled around 0.
Then tonight after a long drive the long terms were back to -10% with short terms around 0. Stopped the car, unplugged and re-plugged the MAF a few times and voila, short terms shot up to 8-10% until long term dropped to -3% and short term around 0.
This is the only documented data I have so far, but all the other times I've managed to get the long term trims to settle down I'm 99% sure I did something with the MAF beforehand, either unplugging it completely or just jiggling it around.
And yes, I already replaced the MAF sensor a while back in hopes of solving the very same issue. In my service notes I wrote that replacing the MAF seemed to have solved the rich reading. But it just kept coming back. Common denominator in the replacement process? Unplugging it.
I don't think it's the O2 sensors. I highly doubt that both of them would fail in perfect sync to result in identical rich readings on both cylinder banks. And when they do go back to acceptable readings, they're off by about 1.5% which seems far more expected for old sensors. Voltage readings from both look totally fine.
Anyway, what can I try short of cutting the MAF plug off and soldering on a new one?
