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Thread: cylinder airmass does huge drop suddenly in boost WOT

  1. #1

    cylinder airmass does huge drop suddenly in boost WOT

    Hi, I have a 2009 e38 ecu with an Ly6, low boost 5 psi, SD 80 lb injectors. At the most dangerous time, without any warning, the cyl airmass drops from 1.07 for example to 0.60 or way lower. The whole time, the throttle position stays wide open, commanded and actual afr doesn't change. Just the nasty reality of lots of spark advance as it's somehow being fooled into thinking it's at a much lower cylinder airmass. I thought I'd play it safer so I reduced the 0.60 cyl airmass timing in case it happened again, and the damn thing went to as low as 0.00 g/cyl which was around 40* timing while in boost.

    I've attached 2 logs where it happens, the title of the logs have the time where the issue occurred in the scan.
    At first I thought it was reduced power mode related but I have disabled p0068 tests and set the p101, 106 and 121 codes to a temperature I won't get up to ever.
    Last edited by Matt_lq4; 05-28-2019 at 10:13 PM.

  2. #2
    Would an SD patch solve this or help at all?

  3. #3
    You aren't logging cylinder airmass. I don't think you are logging enough to see what is happening. At 3000 rpm exactly Dynamic air dropped a lot.
    Last edited by Jeff7577; 06-01-2019 at 09:42 AM.

  4. #4
    Issue is fixed. It was related to the injector wiring being too close to the coil wiring, creating electrical interference/noise. The owner moved his coils a little bit away from the injectors which moved the wiring away also. No more airmass drop, yay.