+ Reply to Thread
Results 1 to 8 of 8
  1. #1
    Registered Member
    Location
    Long Beach, WA, United States
    Member No: 149812 markwascher is an unknown quantity at this point markwascher's Avatar
    Join Date
    Feb 2007
    Posts
    9
    Rep Power
    0


    Yes | No

    new guy e28 M5 running rich?

    Hello, this is my first post.

    My e28 M5 (145k) which I bought a month ago seems to be emitting unburned gases. My garage smells like an ether factory. I recently fixed a fuel line coming out of the fuel filter by the gas tank (no leaks)and replaced a "rebreather"??? hose from the airbox that winds its way down and to the left between the throttle bodies. I had to take all the "trumpets"?? off the throttle assembly to get my fingers under there. The throttle plates look a little carmalized and there was a dab of oil on each of the ports.

    All but one of the rubber O - rings looked good. I cleaned the seats and lubed the o - rings with a thin film of oil before reattaching. I think I got the hoses pretty tight.

    The car smelled rich before the work but I didnt think anything of it. Am I paranoid about missing somthing? yes? Could it be that I have a bad exhaust valve? I am not much of a mechanic but I try. I have pictures but I cant figure out how to post them. Guess I'm not much of a computer guy either.

    Also I seem to have lost 1mpg since the work.



    Any help is much appreciated.


  2. #2
    Registered Member
    Location
    Conroe, TX, United States
    Member No: 136776 Mark_88_M5 is on a distinguished road Mark_88_M5's Avatar
    Join Date
    Jan 2006
    Posts
    529
    Rep Power
    11


    Yes | No

    Have you checked the fuel pressure at the injector

    rail? You may have a failed fuel pressure regulator.

  3. #3
    antony
    Guest
    Location
    , ,
    Member No: antony's Avatar


    Yes | No

    Re: new guy e28 M5 running rich?

    hi mark,

    a fuel pressure regulator failed in the "too high" pressure mode will most likely cause the trip computer to register unrealistically optimistic mileage.

    i'd check your afm for signs of tampering; one smog shop i went to
    adjusted mine way out of whack. if that's the case with yours as well, good luck trying to put it back. it may also just be worn out. i'd also check your o2 sensor output for proper function, although with everything else in good shape, that should not make all that much difference.

    congrats on your purchase; i'm sure it will provide years of entertainment.

    --antony

    p.s. if you (or anyone else) is interested in a dinan or tms/conforti ecu chip, i have both available (i just installed one of scottie sharp's maf conversion kits).

  4. #4
    antony
    Guest
    Location
    , ,
    Member No: antony's Avatar


    Yes | No

    Re: new guy e28 M5 running rich?

    you might also check the air and coolant temperature sensors.

    --antony

  5. #5
    Registered Member
    Location
    Phoenix, AZ, United States
    Member No: 40989 lkfosteraz is an unknown quantity at this point lkfosteraz's Avatar
    Join Date
    Jul 2002
    Posts
    113
    Rep Power
    0


    Yes | No

    Re: new guy e28 M5 running rich?

    I've had my M5 run rich when I didn't replace the gaskets between the headers and the catalytic converter after I replaced my driveshaft. That allowed air to get sucked into the exhaust, which in turn told the oxygen sensor circuit to go rich.

  6. #6
    Todd Frye
    Guest
    Location
    , ,
    Member No: Todd Frye's Avatar


    Yes | No

    Read your plugs.

    I would think the emissions print out from your state inspection would list a specific percentage of hydrocarbons and CO2. This would be a known starting point to diagnose incomplete combustion. Did you get a compression and leak-down test before you purchased your M5? These tests also give very important info on engine health. Pull your spark plugs after a decent warm-up drive, and evaluate: white/lean, light chocolate brown/good, crusty black/not good. Use the plug wrench in your tool kit for plug removal. It works just fine. Start with the basics and hopefully that will get you pointed in the right direction. Good luck. Todd Frye

  7. #7
    Registered Member
    Location
    Long Beach, WA, United States
    Member No: 149812 markwascher is an unknown quantity at this point markwascher's Avatar
    Join Date
    Feb 2007
    Posts
    9
    Rep Power
    0


    Yes | No

    Re: new guy e28 M5 running rich?

    Thanks for all the advice. I had it smogged and everything is cool. A leak down test done prior to purchase showed pretty good results with the largest loss of 14 on number six. the rest were around 10-12. I'll check the plugs next.

    Have a good one everybody.

  8. #8
    Registered Member
    Location
    , ,
    Member No: 12648 ajwong is an unknown quantity at this point ajwong's Avatar
    Join Date
    Aug 2001
    Posts
    424
    Rep Power
    0


    Yes | No

    Leaky/Stuck injectors could do that too...

    <img src="http://home.comcast.net/~wong.andrew/pics/sig.JPG">

+ Reply to Thread


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Bookmarks

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
1e2 Forum