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    #1

    Odd Emissions Failure - Thoughts?

    So thanks to PennDot and Bucks County, an E30 still needs to pass pretty tight emissions standards here.

    This exact same car passed the same emissions test at the same location with flying colors last year. Nothing has changed except I just had the car off the road a few months while I did some bodywork in the rear and rebuilt the suspension.

    Motor is a 2.8 stroker with a 298* Cat Cam and it's running a Miller MAF, but not the WAR chip. It does have a cat converter that was new for last year's inspection (Magnaflow 2.5" generic).

    Just today, it failed by a LONG shot in all three categories: CO, HC, and NO.

    The strangest part in my mind is that the car runs great! It has never pulled as smoothly and as hard as it does since I got it back on the road again last week. It will break loose in second by just easing into the throttle at 4k RPM, haha. Wouldn't do that before.

    My inspection mechanic who is not a foreign car guy told me I should check the timing. That doesn't make sense in my mind, nothing has been altered, not to mention the ignition timing is not adjustable manually correct? Plus the crank to cam timing is normally not adjustable (though I do have an adjustable pulley, it's currently set to 0*).

    If you any suggestions, I'm happy to hear them. Thanks!
    '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black
    Tags: None
    #2
    Check for :
    Vaccum leaks


    Clean:
    AFM
    Idle Air control valve

    Replace:
    O2 sensor
    Coolant temp Sensor

    Fill from Empty new gas
    add: stabilizer/emmissions pass bottle

    Change:
    Oil Change
    Spark Plugs

    Just some things that could possibly help


    When I have to go for emmissions test, I always change the sparks, and do an oil change and do a good check over, keep in mind the lifetime of certain sensors, ie O2, and coolant temp sensor.

    hope that helps
    my build here ---> http://www.r3vlimited.com/board/show...ht=lemans+blue

    Comment

      #3
      Originally posted by sweet6e30 View Post
      Check for :
      Vaccum leaks


      Clean:
      AFM
      Idle Air control valve

      Replace:
      O2 sensor
      Coolant temp Sensor

      Fill from Empty new gas
      add: stabilizer/emmissions pass bottle

      Change:
      Oil Change
      Spark Plugs

      Just some things that could possibly help


      When I have to go for emmissions test, I always change the sparks, and do an oil change and do a good check over, keep in mind the lifetime of certain sensors, ie O2, and coolant temp sensor.

      hope that helps
      Thanks, but I'm afraid that's all been covered. Has no AFM, has a Miller Bosch MAF. IAC was cleaned when the engine was rebuilt (this motor has just 15k miles btw), O2 sensor is 9 months old, same with CTS, has a brand new gas tank as of 3 weeks ago so brand new 93 octane Sunoco, oil change is just a few months old.

      Really just the spark plugs might help if changed, they're the same age as the motor, so 15k miles and a year and half old.
      '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

      Comment

        #4
        Intake leaks, a fuel delivery problem, or a mass flow (air) metering problem can result in all three being high. Partial misfires from a lean condition will elevate all three numbers.
        The car makes it possible, but the driver makes it happen.
        Jim Levie, Huntsville, AL

        Comment

          #5
          Originally posted by jlevie View Post
          Intake leaks, a fuel delivery problem, or a mass flow (air) metering problem can result in all three being high. Partial misfires from a lean condition will elevate all three numbers.
          Wow, do you think the bottom line is that it's lean? I would have guessed the opposite.

          What I still can't figure is why it seems to be running better than ever before?

          I had the intake and exhaust tracts smoke tested just a few months ago. I know the throttle shaft in the throttle body leaks. That was it vac leaks.
          '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

          Comment

            #6
            Running somewhat lean won't necessarily be evident from driving the car. But there could be partial misfires which will elevate CO & HC and the overall lean condition will elevate NOX.

            Correctly done a smoke test will find leaks anywhere in the engine. That means plugging the exhaust, replacing the AFM (or MAF in this case) with a plug that has a connection for smoke, feeding in smoke until a pressure of 2-4psi is reached, and holding that pressure at least 5 minutes. Was the test done that way?
            The car makes it possible, but the driver makes it happen.
            Jim Levie, Huntsville, AL

            Comment

              #7
              Yes, the smoke test was done properly as you described. I should add there were a few small leaks in the exhaust at the slip joints where the headers join the rest of the system.

              I understand running a bit lean may not be noticeable ordinarily, but I'm not exaggerating when I say the car accelerates immensely better than before and pulls more smoothly at high RPM. If that's the result of a lean situation, where was the fuel ratio before? When it passed emissions just fine.

              That's a bit of a rhetorical question, but it just doesn't make sense. I appreciate your help so far though!
              '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

              Comment

                #8
                The ideal AFR for a street car would be 14:1 (stoichiometric). For street performance a bit less (~13.8:1) and on a race car ~13.5:1. As a diagnostic test I'd take the car to a dyno and get the AFR at part and full throttle conditions (and especially at the emissions test speed). That should help in figuring out what is wrong and where to look.
                The car makes it possible, but the driver makes it happen.
                Jim Levie, Huntsville, AL

                Comment

                  #9
                  Originally posted by jlevie View Post
                  The ideal AFR for a street car would be 14:1 (stoichiometric). For street performance a bit less (~13.8:1) and on a race car ~13.5:1. As a diagnostic test I'd take the car to a dyno and get the AFR at part and full throttle conditions (and especially at the emissions test speed). That should help in figuring out what is wrong and where to look.
                  True enough, that would definitely help. Maybe I should break down and buy a wideband O2 finally. I wish I had a readily available dyno locally.
                  '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

                  Comment

                    #10
                    You aren't that far from Allentown, Philly, or NYC. I'm sure you can find a dyno within a reasonable distance.
                    The car makes it possible, but the driver makes it happen.
                    Jim Levie, Huntsville, AL

                    Comment

                      #11
                      You're right I'm sure, I didn't mean it to sound so difficult. I was thinking really local with a shop I was already familiar with that's all.
                      '89 BMW 325is Zinnoberrot / '88 VW Jetta GLI 16v Tornado Red / '89 VW Jetta GLI 16v Tornado Red / '89 VW GTI 16v Bright Blue Metallic / '91 BMW 325i Black / '91 BMW 325i Sport Black / '92 VW GTI 16v Black / '92 VW GTI 16v Montana Green / '01 Audi A4 Avant TQM Silver Metallic / '01 VW Jetta GLX VR6 Black

                      Comment

                        #12
                        Local is always more convenient. But getting the data is more important in this case.
                        The car makes it possible, but the driver makes it happen.
                        Jim Levie, Huntsville, AL

                        Comment

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