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2005 OBXT, replaced battery, big MAF spikes under boost (?)

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So late yesterday I discovered my battery was dead, and being that I suspected it was marginal in the 1st place, I replaced it w/ a Duramax 35-DLG.


During the day today I went to pass someone under only moderate boost and the car fell on its face. Almost felt like boost cut but I noticed my AEM WBO2 reading mid-8.x AFR.


I datalogged the scenario and looks like MAF Voltage is spiking noticeably, sometimes pegging at 5V in 3rd, 4th or 5th by 3300 rpm and 15+ psi boost (my tune caps calculated load at 4 g/rev and caps airflow at 330 g/sec).


I replaced the MAF w/ a new Denso one in mid-May 2015 and it's totally been fine until just today.


Has anyone else seen similar behavior and/or know of suspected causes (aside from a bad MAF sensor itself)?


Is it possible that I knocked into something while just swapping the battery last night? My initial thought is no, since the MAF and the battery are at opposite sides of the engine bay.


I have a GS CAI but have been using their dry element filter since I installed the new MAF sensor so oil contamination shouldn't be a factor. I'll probably pull off the GS box and at least try re-seating the MAF sensor, but not sure that'll help any.


Also, ~2 yrs ago I had a GM/AEM IAT sensor tapped into the outlet end tank of my IPR TMIC, and that IAT sensor was spliced into the factory MAF/IAT wiring during a SD conversion. Perhaps that splice is now compromised/failing?

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Thanks. I pulled up the GS CAI shroud and removed/cleaned the MAF sensor (the wires looked like they did when new but I cleaned it anyway). In case I needed quick access to the MAF sensor again later, I decided to clean up and reinstall the stock airbox/panel filter. Between cleaning the MAF sensor, handling the MAF harness/wiring loom and reinstalling the stock airbox, the MAF voltage spike issue went away (for now, at least).


I edited my calibration file to restore stock MAF scaling, and as fahr_side and probably others have mentioned, the stock scaling is really rich (like 9.5 AFR on 10.8 target). So back to CL/OL MAF scaling and all that fun stuff.

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