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  • #46
    Originally posted by HANDBLT View Post
    that is spark. There is either a loose/dirty connection on the coil or a ground somewhere braking connection,. or the output on pin #1 of the ECU ( the black shielded wire) is going and coming,

    T
    There are no loose or dirty grounds on the car. None. It doesn't happen when I hit a bump, it only rears its head randomly when its below 60 degrees F. The coil is a new coil, the wires are new. Yes I assume its electrical, but I'll be damned if I can find it. In the afternoon, 85+ degrees, rough road (like might as well be dirt, in a war zone.) nothing, Not a hint of an issue. Under 60 degrees, first thing in the morning, on a smooth freshly paved road, the engine cuts.

    Will
    '69 Datsun 2000 Roadster vintage race car (Street driven on a regular basis :taz
    '59 Alfa Romeo 101 Sprint (HUGE project :uhoh
    '88 M3

    Comment


    • #47
      Not sure if has been mentioned did you expose and look at the fusible link which is located close to the battery + terminal lead and provides power to pumps DMW etc, they can crack.
      p/n

      E30 M3 1987
      Mini Clubman GT
      BMW E36 323 Msport
      Toyota Corona
      KTM 200EXC
      Honda CB50 (1979)

      Comment


      • RAD2LTR
        RAD2LTR commented
        Editing a comment
        The fusible link appears to be fine. I did not cut the heat shrink around it off, but it was protected by the plastic piece, as well as the large main wire. There appears to be no heat damage to it. I would assume that if it were arcing there would be some melted heat shrink around the area, or at least discolored area. This looks perfect. I'm hesitant to cut it open without having a new one on hand.

        The drive home after work was totally normal. I had no issues at all.

        Will

    • #48
      I would remove the insulation due the problem it cracks and causes intermittent power loss
      when this has happened in previous M3s there has been no external visual indication of a problem

      E30 M3 1987
      Mini Clubman GT
      BMW E36 323 Msport
      Toyota Corona
      KTM 200EXC
      Honda CB50 (1979)

      Comment


      • #49
        Ah, ok, I guess I should go find a 50 amp fuse to replace it with since there is no way I'll be able to order the real part, and get it installed before I need to leave on a trip in a week.

        The trip to work was totally uneventful this morning. Car ran great. The air temp was 55 degrees also.

        Will
        '69 Datsun 2000 Roadster vintage race car (Street driven on a regular basis :taz
        '59 Alfa Romeo 101 Sprint (HUGE project :uhoh
        '88 M3

        Comment


        • #50
          Still can't get to the bottom of this. I've replaced the flywheel sensors, the relays, plugs, wires, and coil, the fuel pumps and filter, bypassed the fusible link, and put a different battery in the car. It now bucks and snorts almost every day, after 5-15 minutes of driving, and still, only in the morning. It starts fine in the morning. Runs great until it starts to hard cut, like the ignition is being turned off, and back on rapidly until it finally quits. Once restarted (sometimes takes some effort) its usually fine. The water temp reads warm, the oil about 160 when it starts cutting out. In the afternoon when temps are warm I've never once had an issue. I'm thinking it must be the DME. I'm not sure what else it could be.

          Will
          '69 Datsun 2000 Roadster vintage race car (Street driven on a regular basis :taz
          '59 Alfa Romeo 101 Sprint (HUGE project :uhoh
          '88 M3

          Comment


          • #51
            sounds like the infamous pin #1 of the DME issue. remove all the cover panels from the ECU so you can get to the DME connector. crank the car, now push up and down on just the DME connector and see if it stumbles. This is where mine had an issue. or while driving and it starts acting up reach over and push up or down on the connector and see if it clears up.

            T

            Comment


            • RAD2LTR
              RAD2LTR commented
              Editing a comment
              Wouldn't it do its thing all the time, morning, afternoon or night? Especially over rough roads? This is only doing it in the morning, on smooth roads. I checked all the pins when I had the DME out last week and they all seemed fine. Nothing moved. If it were the pin 1 deal I'd have to guess it would do this at any time, not just in the morning.

              Will

          • #52
            Did you inspect (open and clean) the ground connector next to the ECU? This is a fastener that holds several brown ground wires.
            The OBC relay can also cause strange problems, but IIRC those are usually of the no-start variety. Still might bear a look.
            The last thing, has your coolant temp sensor been tested?

            Comment


            • #53
              What does the rev counter do when the car dies and splutters, does it go down with revs or does it cut out and go to zero and then spring back up when it fires.

              E30 M3 1987
              Mini Clubman GT
              BMW E36 323 Msport
              Toyota Corona
              KTM 200EXC
              Honda CB50 (1979)

              Comment


              • #54
                tach stays reading correctly. It does not drop to zero when the engine cuts. No instruments change/stop working. The stereo stays on, heater fan ect all are unaffected.

                Will
                '69 Datsun 2000 Roadster vintage race car (Street driven on a regular basis :taz
                '59 Alfa Romeo 101 Sprint (HUGE project :uhoh
                '88 M3

                Comment


                • #55
                  Originally posted by HANDBLT View Post
                  sounds like the infamous pin #1 of the DME issue. remove all the cover panels from the ECU so you can get to the DME connector. crank the car, now push up and down on just the DME connector and see if it stumbles. This is where mine had an issue. or while driving and it starts acting up reach over and push up or down on the connector and see if it clears up.

                  T
                  Did you do what I asked and pushed up and down on the connector while running or while cranking to see if it replicates the same issue?

                  T

                  Comment


                  • #56


                    I should have asked earlier on, If the rev counter stays level and the engine dies down this would indicate that the DME relay and the power supply to the DME are functioning correctly, otherwise the rev counter would die down then spring back to life with re-fire.

                    Would also indicate that the RPM signal is being picked up from the flywheel, (otherwise no RPM signal sent to the rev counter).

                    This would also rule out a problem with the cut out relay / anti theft green box under the steering column.



                    So what does that leave?

                    Everything fuel related, from the pump relay to the pumps (new pump did not fix it so can rule that out)

                    Fuel pump relay causes either non starting or intermittent non start so probably not that.

                    Injection reference signal(new rule that out)

                    Throttle reference sensor, (it would have to think it was still idling like when you pull the plug off the engine wont rev up)

                    Ignition high tension, coil, cap and leads ( if any one of these things it would be often and under load not one hick up once a day)

                    DME water temp sensor(hard starting and flooding/ running rich is the normal failure mode with these)

                    AFM- usually the track gets worn through and it is usually in the part of the board where the wiper points spend there most time, light to mid throttle.
                    Mine worn through and it would have to be at a constant cruse at exactly the right speed and it would momentarily cut out once. Mine did it twice over about 5-6 trips before I lifted the AFM plastic lid and reset the points. Highly recommend lifting the plastic lid for a looksee.

                    DME - visual inspection if it was bad you should see heat indications at suspect solder joints otherwise you need to go over it with a magnifying glass to see the not so obvious dry joints. Best thing to do is swap it out.

                    What Hand built is recommending sounds well worth a try and general tapping of the plug and DME while engine running.


                    Barometric pressure sensor, not sure what the failure mode is and associated symptoms for this one.

                    Earth points, if you clean them all you can’t go wrong.



                    Don’t wait until you have a problem.
                    Fuel pump and DME relays, TPS, DME water temp sensor, these items are not expensive and for the age of our cars if you have not replaced them you should just as preventive maintenance items even if you don’t have any problems.



                    I have probably missed a few things out, please add your symptom and route cause/fix.

                    Dave.



                    E30 M3 1987
                    Mini Clubman GT
                    BMW E36 323 Msport
                    Toyota Corona
                    KTM 200EXC
                    Honda CB50 (1979)

                    Comment


                    • #57
                      Originally posted by Dave @nz View Post

                      I should have asked earlier on, If the rev counter stays level and the engine dies down this would indicate that the DME relay and the power supply to the DME are functioning correctly, otherwise the rev counter would die down then spring back to life with re-fire.

                      Would also indicate that the RPM signal is being picked up from the flywheel, (otherwise no RPM signal sent to the rev counter).

                      This would also rule out a problem with the cut out relay / anti theft green box under the steering column.



                      So what does that leave?

                      Everything fuel related, from the pump relay to the pumps (new pump did not fix it so can rule that out)

                      Fuel pump relay causes either non starting or intermittent non start so probably not that.

                      Injection reference signal(new rule that out)

                      Throttle reference sensor, (it would have to think it was still idling like when you pull the plug off the engine wont rev up)

                      Ignition high tension, coil, cap and leads ( if any one of these things it would be often and under load not one hick up once a day)

                      DME water temp sensor(hard starting and flooding/ running rich is the normal failure mode with these)

                      AFM- usually the track gets worn through and it is usually in the part of the board where the wiper points spend there most time, light to mid throttle.
                      Mine worn through and it would have to be at a constant cruse at exactly the right speed and it would momentarily cut out once. Mine did it twice over about 5-6 trips before I lifted the AFM plastic lid and reset the points. Highly recommend lifting the plastic lid for a looksee.

                      DME - visual inspection if it was bad you should see heat indications at suspect solder joints otherwise you need to go over it with a magnifying glass to see the not so obvious dry joints. Best thing to do is swap it out.

                      What Hand built is recommending sounds well worth a try and general tapping of the plug and DME while engine running.


                      Barometric pressure sensor, not sure what the failure mode is and associated symptoms for this one.

                      Earth points, if you clean them all you can’t go wrong.



                      Don’t wait until you have a problem.
                      Fuel pump and DME relays, TPS, DME water temp sensor, these items are not expensive and for the age of our cars if you have not replaced them you should just as preventive maintenance items even if you don’t have any problems.



                      I have probably missed a few things out, please add your symptom and route cause/fix.

                      Dave.

                      Fuel pumps are new, as are the relays.

                      Throttle reference sensor, new last year, when that died the RPM just hung at 1500.

                      Ignition high tension. New, all of it.

                      DME water temp sensor, new.

                      AFM- possible, but the wiper was reset to a new track a couple years ago.

                      DME inspection- checked it over with 30X magnification, found nothing suspect.

                      Barometric pressure sensor, disconnected

                      All the grounds... all cleaned and tight.

                      I'm trying to get over to see Bill Arnold and borrow a DME to see if that is the culprit, but I just haven't had the chance to get out of work in time to drive there before he closes.

                      Will
                      '69 Datsun 2000 Roadster vintage race car (Street driven on a regular basis :taz
                      '59 Alfa Romeo 101 Sprint (HUGE project :uhoh
                      '88 M3

                      Comment

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