2001 GEN3 6.0 swap in a S10 Blazer been Banging my head trying to find out why my fuel trims go to hell with the MAF plugged in and failed in SD mode. with the sensor failed and maf tables zereoed out I get 3000hz when I plug the MAF in while its running. plugged and unplugged the MAF while its running in scan log. Starting to wonder if its wired like a LS7 MAF or if its just a junk MAF. Been through the harness and cant find anything out of the normal and MAF connector pinned correctly for the year of the 0411 PCM being used.
PN on MAF is Mostplus
M3211Y 342030
It's a Chinese knock-off ... don't use that, throw it away. Even if it WORKED, no two report alike, so when it dies in a few months to a yr as they do, when you replace it, you will have to re-tune the MAF. Just use the GM part here: https://www.amazon.com/Delphi-AF1004.../dp/B000CGFHBY
Threw another MAF on from my Tahoe just for the hell of it and it does the same thing. What's strange is I have 1.9v on IAT signal wire and 2.5v from the MAF signal wire in SD mode. Havent checked it in mixed mode yet. It all goes away and seems to run better in mixed mode, wondering if this is one of those 0411 PCMs that cant be tuned unless the MAF is unplugged ? Im having the exact same symptoms that some other members have posted about.
Leaning towards a possible PCM issue now.
I dont get why the O2 sensors go nuts when the MAF is plugged and unplugged. It was originally a 4.3 PCM that I segment swapped the data to and wonder if their are hidden parameters that HPtuners cant swap over.
The MAF is going to output a signal in hz any time it is plugged in even if it's failed in SD. Your posts are not clear but I think that is your confusion. And using terms like O2 sensors go nuts is not a helpful way to describe what you perceive to be a problem. Narrow band O2 sensors oscillate from about 100 mv to 900 mv when they are working correctly in closed loop.
Its been a long day of no progress sorry.
I'm referring to the log I posted, with the MAF unplugged 0hz, the narrow band o2s peg out at 940mv or so and don't oscillate, then with the MAF plugged in the narrow band goes to almost 0 volts and 3000HZ. For some reason I cant get good log data of the AFR when the MAF sensor is plugged in and failed in SD mode. Here is a couple more logs of how my AFR looks when trying to tune in SD mode with the MAF failed but plugged in.
Going to try and unpin the MAF signal wire from the PCM and see if that will allow to log with MAF plugged back in so the IAT data can be logged.
Sorry can't look at your log or tune files. But if your O2s don't oscillate it sounds like you are not in closed loop. If you are tuning in open loop they won't oscillate. And if the MAF is failed correctly it doesn't matter if the MAF is plugged in or not other than the IAT. MAF outputting 0hz or 3000hz, the pcm is ignoring it's output.
Pretty sure it was a bad PCM ! After downloading a new calibration, my fuel pump cycled and then stayed running but the vehicle wouldn't start. Now it wont take another calibration at all. just get controller timed out message.
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