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Failed Emissions... AGAIN

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    Failed Emissions... AGAIN

    First off, this in in my M50 powered E34.

    Trying to get my car to pass DEQ. Failed first try, then did the following and failed again:

    Replaced O2 sensor
    Replaced cam position sensor
    Replaced VANOS solenoid

    ^^^ These three thought I had it fixed as the car runs much better now and I gain 4mpg.

    Checked coolant temp sensor - Good
    Check air intake temp sensor - Good
    Check throttle position sensor - Good
    Check wiring from all sensors to ECU
    Swapped out MAF for a junkyard one - No change
    Cleaned MAF, both original and junkyard one
    Checked fuel pressure at the rail - Good while engine off and running
    Replaced coils
    Replaced spark plugs

    Recently I've also:
    Had injectors cleaned and flow tested - 1.5 years ago
    Replaced fuel pressure regulator - 1.5 years ago
    Replaced fuel pump and filter - 3ish years ago
    Rebuilt Vanos - 6 months ago

    I'm running out of ideas. I'm thinking I'll get it smoke tested to verify no vacuum leaks, though I don't think there are any. Only other thing I can think of is bad cat perhaps?

    Attached Files

    What are you running for a cat?




        The high hydrocarbon is unburned fuel. This can be caused by any number of issues. Do the smoke test and check spark plugs (seeing what color the tips are should help find any issue areas)


          I bet it would pass with a new cat. I have put a few cats on my car over the years and when they fail (for me) it showed up as high HC every time.

          Originally posted by slammin.e28
          The M30 is God's engine.


            Looked up the cat. It's specific to E34iX, I'm guessing due to how it fits around the transfer case. Schmiedmann lists it, but it's $1500+shipping from Denmark!!!

            My valve cover gasket is leaking a bit, so I think I will start there.


              If they aren't testing for NOx, put a ton of E85 in.
              2006 GMC Sierra 2500HD 4WD LBZ/Allison
              2002 BMW M3 Alpinweiß/Black
              1999 323i GTS2 Alpinweiß
              1995 M3 Dakargelb/Black
              - S50B32/S6S420G/3.91
              1990 325is Brilliantrot/Tan
              1989 M3 Alpinweiß/Black

              Hers: 1996 Porsche 911 Turbo Black/Black
              Hers: 1988 325iX Coupe Diamantschwartz/Black 5spd



                An exhaust shop can put in a generic cat.
                AWD > RWD