85 320i (euro) m50 finishing touches

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  • thonnas
    Noobie
    • Jan 2009
    • 9

    #1

    85 320i (euro) m50 finishing touches

    Alright, I've got my engine in, running, certified and smogged, but have a few little things that I need some help with.

    First, and most importantly, I seem to be hitting some kind of rev limit at around 3500. This only happens on the road, as it will gladly growl up towards 5k at idle. I thought it might have been the fuel pump, so I pulled one off of a 325, and there was a noticeable performance boost, but she still caps out at around 3500 rpms on the road. If you really slam the accelerator it will eventually struggle up higher, but it's very unpleasant.

    Do I need to run this wire I've read about to the back of the tach? This doesn't quite seem like the issue those people had. If I do need this, can someone please be explicit about where it goes. The things I read have been conflicting/confusing.

    If this isn't the problem, what is? Do I need a special fuel pump? It feels ready to take off at 3k, but then it hits a brick wall and feels like someone is tapping the brake.

    My second "issue" is regarding a little set of service indicators in the bottom center of the console. I imagine they don't get the right signals from the new computer, so they are making a variety of semi-distracting flashes. Can these be rewired to actually be useful, or can I cut them without any problems? I like the overhead problem indicators, and want to keep those, if the two are somehow related.

    To be perfectly clear, I'm talking about the very bottom indicators that say something like "service" and something else, and has a series of lights that go from green to yellow to red. I think it originally indicated "time" since last service (3k miles) or something like that.

    Other than this stuff, it runs great. Just need to get a better muffler, a new top (half cab), and maybe a layer of paint.
    Last edited by thonnas; 04-14-2010, 02:02 PM.
  • 7pilot
    E30 Addict
    • Feb 2009
    • 475

    #2
    Do you have the ROAD speed signal going from the instrument cluster to the DME?
    Check your wiring against the ETK, for the donor DME, the Donor harness and the recipient chassis.

    If you do not, then this lack, or a bad cam shaft position sensor, may be to blame.
    The ETK also show the circuits for the service interval indicator.

    m

    Comment

    • sharky
      R3VLimited
      • Jan 2005
      • 2672

      #3
      yes you need to tap a green wire in your cluster related to the road speed signal, soft limits under load via signal from the diff

      Reset your si board or just get rid of it (bulbs)

      Comment

      • thonnas
        Noobie
        • Jan 2009
        • 9

        #4
        ok, so it goes to the speedometer? do I have to tap into the actual panel, or one of the wire harnesses going into it?

        The ETM (e34_95) shows 4(?) wires going to the instrument panel (47, 42, 8, 46). I'm not sure what the dashed lines mean, but 47 and 46 look to be related to transmission control (EGS), so I'm guessing 8 is the one I want, but I don't see any colors, and am not sure how I'd identify it by pin with the way the connector is. Is it the only green one? And can I cut it, or does it need to be tapped into. I actually have a spare wire coming from the harness that I may have put for just this reason. Is it pin 14 on the wiring harness? I think I just never figured out where to put it it.

        So, where exactly does it go?

        The ETM (e30_85) shows a speed input at number 12 (br/rd) on c2 connector. Will that work? The only speed out looks to go to a connector (for cruise control) that I don't think exists on my e30. I only have the c1 and c2 connectors.

        ---
        I see the stuff for the service interval indicator, but as you can probably tell, this isn't exactly my area of expertise. What can I do with it?
        ---

        Also, I completely forgot about it this, but my low fuel light seems to be backwards. It's on when full, and looks like it goes off when actually low. Is this a bad ground somewhere? or might something else be hooked up wrong?

        ----

        I don't think the service interval indicators are working properly, so I doubt reset would help.
        Last edited by thonnas; 04-15-2010, 09:28 AM. Reason: I think I understand, now.

        Comment

        • thonnas
          Noobie
          • Jan 2009
          • 9

          #5
          Can anyone at least help me figure out where to run the wire, seeing that I have no cruise control connector on my cluster?

          Comment

          • thonnas
            Noobie
            • Jan 2009
            • 9

            #6
            alright, after doing some more searching I found this bad boy:


            While I don't have a c3 connector, the yellow plug is there on the back of the cluster. I'll see if I can find something to hook into pin 26 there and run it to pin 14 on the x20.

            I got the impression that using pin 12 on c2 is not a good idea.

            Comment

            • thonnas
              Noobie
              • Jan 2009
              • 9

              #7
              So, I found an old computer audio connector that hooked up quite well to the pins, spliced it to the wire I had running from the harness and put everything back together.

              Worked great, except for one thing. I had a little smoke coming out of the console. I think maybe the wire on the audio connector is too small, but if it fried I would have expected the rev limiter to kick in. How much current is running through this wire?

              I only drove it to the store and back, not wanting to tempt fate. I didn't really notice any smoke on the way home, so I'm also thinking it may have just been a bit of "burn in" since there has never been anything hooked up to that connector on the console. Now I'm pondering give it another spin before I crack it open again to take a look.

              I also hooked up a stereo (haven't had one since putting the swap in) and there is a fairly noticeable buzz directly associated to rpms, so I'm almost certain I have a bad wire running to ground somewhere. Guess I'll have to break out the wiring diagram and double check everything again, otherwise, anyone have any tips?

              Also, I'm happy to keep talking to myself, but if someone wants to reaffirm me on any of this, that would be awesome, too.

              Comment

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