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Reply To: Might stump ya! 08 suburban 5.3l rich and evap

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here Might stump ya! 08 suburban 5.3l rich and evap Reply To: Might stump ya! 08 suburban 5.3l rich and evap

Nightflyr *Richard Kirshy

    Let me see if I have this correct..
    1 You had a miss fire, but not running rich or had a EVAP code.
    2 Replaced the injectors with after market replacements and ended up running rich.
    3 then you began tinkering to correct the rich fuel trims and ended up with EVAP issue.

    Let me take a shot in the dark…
    First question: The MAF you replaced, did you install OEM or aftermarket?
    My second question: Exactly how did you determine the injector was the cause of the miss fire.
    Assuming it was, due to the fact you do not state it was miss firing after replacing them.

    Something is telling me you may have more than one issue happening at the same time

    The rich condition may be due to the after market injectors.
    You say : Then its been reading rich off n on ever since and by off and on its narrowing it down to a reading that is out of norms …
    My thinking is the ECM took awhile to remap itself to the new injectors which maybe under performing, which in why you have higher trim levels.
    You may well need to go and install OEM parts to solve that issue.

    As to the EVAP …
    It may well be causing your fuel trims to be high.
    But because they are aftermarket they could also be suspect.
    With my issue …
    For over a year I would get varying readings on my fuel trims but never a code.
    Then one day I happen to check the readiness monitors and found the EVAP was incomplete.
    Looked over everything but never saw any issue, the next time I checked the monitors all were good.
    Finally after last winter the EVAP monitor failed again.
    After a month it never completed.
    Went and got a smoke machine, couldn’t locate a leak to save my life.
    Finally as I was rustproofing I happen to notice that the purge valve mounted to the carbon canister didn’t look quite right.
    Got a mirror and flash light and saw it was split at the mounting flange.
    There was the cause.
    All the time leading up to the full time failure of the EVAP monitor was due to the purge valve somehow sealing itself.

    My suggestion:
    First go after the EVAP issue once repaired, see where your fuel trims settle at.