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  1. #1
    Veteran Member Four Rings
    Join Date
    Oct 21 2005
    AZ Member #
    8454
    Location
    y

    Runs rich til boosted - FPR, Leaking Inj etc?

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    Has anyone have an FPR fail cause it to run rich? I think mines stuck closed til boosted. Haven't done fuel pressure check yet.

    Mine runs so rich that at WOT around 3krpm itl bog and max out AFR gauge (can only display up to 11). Probably also the reason why my plugs foul so quickly. Before I gapped my plugs (.26 before, now .34), it was misfiring causing it not display proper afrs (shows lean when rich) until I boost it, with .26 gap afr was around 14 warm-idle, with .34 its 11-12 warm-idle.

    With .26 gap the misfire wasn't even that bad, it was just the occasional hiccup/hesitation. With the .34 gap it doesn't misfire = shows proper AFRs.

    The only thing that seems to work is a single boost run, AFRs goes to the proper levels. .34 plug gap 14-15afr warm idle, 14-15afr part throttle, 13.5afr WOT 0psi.

    Boost run = increase rpm slowly til around 5k, then floor it.

    I don't think it's the wideband sensor (displays super rich that coincides with the bog) or tune/ecu adapt (stock ecu warm-up maps were zeroed out for testing - before it even occurred to me to check the inj duties)

    Some data:
    AEB - stock ecu+ piggyback - running open loop.
    stock 4bar fpr
    870cc
    Mafless

    Logs from Vagcom and piggyback
    CTS - 189F
    IAT - 100F

    Pre-boost
    3000rpm
    0psi
    Throttle - 100%
    Inj Duty around 9%
    Pegged gauge
    Car bogs


    2500rpm
    Throttle - 8%
    Inj duty 4%
    AFR 12.5

    Idle
    Inj duty 1%
    AFR 11.5


    After boost run
    3000rpm
    0psi
    Throttle - 100%
    Inj Duty around 9%
    13.5 afr til it sees boost then richens as tuned.

    RPM - 2500
    Throttle - 8%
    Inj duty 4%
    AFR - 15.2

    Idle
    Inj duty 1%
    AFR 14.5

  2. #2
    Veteran Member Four Rings
    Join Date
    Oct 21 2005
    AZ Member #
    8454
    Location
    y

    other info:

    Cold Voltage (running engine) 13.2 volts
    Warmed up - 12.6-12.8volts

    N80 disconnected - this thing caused the engine to stall in the middle of the road a couple years back.

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