help me raise my idle

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • lifeiskaos
    E30 Mastermind
    • Dec 2007
    • 1709

    #1

    help me raise my idle

    so, my idle is really low, about 600. it's always been this low. when it was bone stock, and now with 19lb injectors and an m30 afm. i have adjusted the gear in the afm so i believe it's at the best setting now, but it still runs rich at idle and it's really low. sometimes when i first start the car, it will run really roughly (400-900 rpm jump), and sometimes when it finally idles, it will smell like fuel and the check engine light will turn on until i r3v my engine. so, how can i lean out my idle and hopefully raise it a few rpms?
  • CarsSuck
    E30 Modder
    • Oct 2005
    • 968

    #2
    That really sounds more like a leaking vacuum line. There are a multitude of little hoses connected to the throttle body and intake mani. any air leak after the AFM will make wierd things happen.

    Adjusting the AFM isnt a good idea without a means of precisely seeing what it does to the air/fuel ratio.

    Also check and clean the idle air control valve.
    --Will

    Comment

    • redhatpat
      Mod Crazy
      • Aug 2005
      • 656

      #3
      The AFM is non-adjustable. Don't fuck around with it. Something else is wrong with your car.

      Comment

      • lifeiskaos
        E30 Mastermind
        • Dec 2007
        • 1709

        #4
        ok, well i'll check for vacuum leaks. all the metal connectors to the throttle body are pretty much loose and stripped... air could be getting in through that. i know where the stock afm gear position gear was, so i could always put it back, i've just heard that a lot of people said it ran best when the spring was loosened two click of the gear. any other advice? i didnt think it'd be a vacuum leak because it's so rich, and i figured extra air would mean lean, not rich

        Comment

        • scabzzzz
          Estado de mierda de encargo
          • Jul 2007
          • 6870

          #5
          Well, more fuel and more air. Got the programming to boot?

          Comment

          • lifeiskaos
            E30 Mastermind
            • Dec 2007
            • 1709

            #6
            Originally posted by scabzzzz
            Well, more fuel and more air. Got the programming to boot?
            no, im running stock chip. i figured, it was built to adjust the air and fuel mixture, why can't it do the same with my setup? it does run very well, throughout the range. i did find one leak, so the idle isnt rough anymore, but its still on the low side and if i rev the engine, it will drop to about 400 rpms, almost stall (lights dim), but then it'll recover. do i really need a chip, or is there something that controls the idle that i can adjust?

            Comment

            • nando
              Moderator
              • Nov 2003
              • 34827

              #7
              there is nothing you can do to adjust the idle - all you can really do is make sure there are no leaks and everything is working (clean/working ICV, properly adjusted TPS, etc).

              aftermarket chips tend to leave the idle stock anyway
              Build thread

              Bimmerlabs

              Comment

              • Aptyp
                R3V OG
                • Feb 2008
                • 6584

                #8
                there is a way to adjust AFR on m20s, it's an allen bolt on your AFM, usually covered by a little blue cap so no one would ever mess with it. You do need proper equipment and knowledge.

                Comment

                • James Crivellone
                  Head Janitor
                  • Oct 2003
                  • 6297

                  #9
                  You have something else wrong, however if you want to raise the idle a little you can jump the ECU to make it think the A/C compressor is on. That raises it a little bit.

                  Comment

                  • lifeiskaos
                    E30 Mastermind
                    • Dec 2007
                    • 1709

                    #10
                    lol thanks guys. problem was fixed over a year ago

                    Comment

                    • nando
                      Moderator
                      • Nov 2003
                      • 34827

                      #11
                      Originally posted by Aptyp
                      there is a way to adjust AFR on m20s, it's an allen bolt on your AFM, usually covered by a little blue cap so no one would ever mess with it. You do need proper equipment and knowledge.
                      that's only on early M20s

                      Originally posted by lifeiskaos
                      lol thanks guys. problem was fixed over a year ago
                      this
                      Build thread

                      Bimmerlabs

                      Comment

                      • awakenthedead
                        Noobie
                        • Jun 2011
                        • 5

                        #12
                        i got an 87 325 with this same problem. but i have no vac leaks. how did you fix yours? if i go the jumper route what pins should i jump? would they be the ones in the ECU or the ICM?

                        Comment

                        • jlevie
                          R3V OG
                          • Nov 2006
                          • 13530

                          #13
                          The most common causes of this are intake leaks, a sticky or bad ICV, a bad or misadjusted TPS, or an aged O2 sensor. The only sure way of tell if there are intake leaks is to have a smoke test run. The O2 sensor has a useful life of 100k and is a scheduled maintenance item. There are other possibilities, but work through those possibilities first.
                          The car makes it possible, but the driver makes it happen.
                          Jim Levie, Huntsville, AL

                          Comment

                          • awakenthedead
                            Noobie
                            • Jun 2011
                            • 5

                            #14
                            jim, ive been chasing this idle problem for 3 months. i tallied up today how much ive spent on parts and diagnostics and smoke tests to be told by several shops that they cant find out why my car wont idle right. ive spent $2176.71 i could have bought a good working truck for that. i love this car. its uber fun to drive but i cant keep tossing money at a problem that evidently no one can find to actually fix. if soldering a jumper in the ECM or the ICM so my car thinks the a/c is on and keeps the idle where its supposed to be, then thats what i want to do. im at a lose of other options.

                            Comment

                            • MTechnikII
                              Member
                              • Jun 2007
                              • 83

                              #15
                              I'm just reading this posts,
                              here is my experience with idle on my 91 325i.
                              new FPR, New plugs , new AFM, working ICV, New ECU temp sensor, and still rough idle.
                              my mistake awas I was following the Bently's recomended gap for valeve adjustment,( not to mention terrible 10, 11 MPG) I readjusted the valve clearance to about 10% bigger than what Bently was suggesting and everything fell in it's place , immediate smoother idle and immediate increase in MPG it went from 10 - 11 to 17-118 MPG
                              try the valve clearance adjustment and also regap the spark plugs to about 10% bigger than recommended in Bentley manual, you will have a better idle if there is no leak .
                              hope this was helpful
                              Henry

                              Comment

                              Working...