serx7 Posted January 3, 2017 Share Posted January 3, 2017 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? Link to comment Share on other sites More sharing options...
ehsnils Posted January 4, 2017 Share Posted January 4, 2017 I'd start with the splice and then clean the MAF too. Link to comment Share on other sites More sharing options...
serx7 Posted January 5, 2017 Author Share Posted January 5, 2017 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. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.