Announcement

Collapse
No announcement yet.

Confusing Smog Test Results

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Confusing Smog Test Results

    Greetings all. Not an e30 question but an e24/m30 problem.

    I recently purchased this vehicle (1986 635CSi) and have been having some issues with passing a California smog test. My smog test guy has been helping me out by giving me a pre-check to get things sorted out prior to the official check. The big issue, at first, was high HC. The first checking I did had the HC come in at 1300 at idle. I changed the O2 sensor, air filter, gave it an oil change and replaced the fuel pump (the one on the car was not correct). Doing all this brought the HC down to 300. A lot better but still too high. The catalytic converter in the car was suspect so I had a new Magnaflow unit installed. HC problem solved! However, this is what happened...

    Everything looked great but the 25mph NO went through the roof! How could the NO go from 1 at 15mph to 2704 at 25mph and the same RPM? I don't get it.

    Has anyone dealt with this before? Faulty test equipment? AFM perhaps?
    1 Photo
    Tags: None
    #2
    300? the test shows HC dropped down to 13 and 5! which is too lean and when you lean out too much NOx goes up. Did he fool with the AFM? You need to richen the mixture to get NOx down. Looks like you have plenty of room provided the cat isn't damaged. Testing for vacuum leaks wouldn't hurt either.
    "I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj

    85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
    88 M3 - LACHSSILBER/SCHWARZE
    89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
    91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER

    Comment

      #3
      Originally posted by reelizmpro View Post
      300? the test shows HC dropped down to 13 and 5! which is too lean and when you lean out too much NOx goes up. Did he fool with the AFM? You need to richen the mixture to get NOx down. Looks like you have plenty of room provided the cat isn't damaged. Testing for vacuum leaks wouldn't hurt either.
      I'm considering swapping the AFM from my E30 onto the E24 and giving it a try. Also, I should probably look at the fuel injectors.

      Comment

        #4
        You have a big six AFM on your E30? They used to be plentiful at the yards but nowadays they are hard to find in good condition.
        "I'd probably take the E30 M3 in this case just because I love that little car, and how tanky that inline 6 is." - thecj

        85 323i M TECH 1 S52 - ALPINEWEISS/SCHWARZE
        88 M3 - LACHSSILBER/SCHWARZE
        89 M3 - ALPINEWEISS II/M TECH CLOTH-ALCANTARA
        91 M TECHNIC CABRIO TURBO - MACAOBLAU/M TECH CLOTH-LEATHER

        Comment

          #5
          Originally posted by reelizmpro View Post
          You have a big six AFM on your E30? They used to be plentiful at the yards but nowadays they are hard to find in good condition.
          You're right.

          realoem said that they had the same AFM. However, after further examination it's clear that they're different.

          Comment

          Previous template Next
          Working...
          X