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Z3M S50 -two questions

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  • Z3M S50 -two questions

    Hello everyone !☺


    1.When I switch-off (ONLY WARMED)engine,and turn on for a few seconds-minutes and hold gas pedal between 2000-3000 rpm(IN STAND) ,then rpm fluctuating-oscillates 2000-2500 rpm...And jerks in ride(2000-3000rpm)...After 5-10 min. everything is okay...
    Rpm in idle is ALWAYS okay(newer oscillates)...
    I have a video...

    2.how pre-load center support bearing on car(I don't marked the position when I took off the driveshaft(I have vibration in the 1st and 2nd gear in back under acceleration)...


    Thanks in advance!

  • #2
    I relation to number 1, that sounds suspiciously like the vanos to me, perhaps the solenoids.

    On my partners roadster it was jerking at low rpm. I installed new vanos seals which appears to have made it go away

    Thanks

    Martin
    Last edited by mnbrennan; 18-10-2016, 06:43 AM.

    Build thread: https://www.z3mcoupe.com/forum/showthread.php?t=19347

    Comment


    • #3
      Vanos was repaired before 15.000 km-Dr.Vanos.
      Hot pressure is 100 bar

      Comment


      • #4
        Originally posted by Z3 M roadster View Post
        2.how pre-load center support bearing on car(I don't marked the position when I took off the driveshaft(I have vibration in the 1st and 2nd gear in back under acceleration)...
        Make sure the Prop Front Coupling (donut) is tight and torqued to the Gearbox Output Flange.
        Then make sure the Prop Rear UJ is tight and torqued to the Diff Input Flange,
        Then loosen the Prop Centre Bearing Nuts (2x) slightly so the Centre Bearing can move a little bit.
        Tighten it up finger tight to 'pinch it' in place where it wanted to rest naturally.
        Then Tap the centre bearing towards the front of the car (Gearbox side) by 2-3mm evenly on both side.
        Now tighten the 2x Centre Bearing Nuts and torque them (usually 25nm if it's M8 thread).
        Now your Centre Bearing is pre-loaded.

        It would also be a good time to check the joint which holds the 2 pieces of your Propshaft together in the middle.
        It's usually a threaded ring to tighten up to clamp the splined section tight.
        Part No. 7/8 on this diagram: http://www.realoem.com/bmw/enUS/show...diagId=26_0105

        Best regards,
        James :)

        Comment


        • #5
          Thank you very much James! :)

          Part 7/8 must be tighten!

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          • #6
            Does anyone know what causing my first problem?

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            • #7
              I don't have a firm answer for your first question, however, the secondary air pump I think is only active during the first few minutes of running - if there was a fault here it could disappear when the car is up to normal operating temperature.

              My Vanos played havoc with idle ( would stall) and was reluctant / slow to rev. Worth double checking the solder connections, or resistance on the solenoid plugs. If you unplug the solenoids check the impedence between the pins on the lead connected to the solenoid - from memory they are around 5 Ohm, much more than this would indicate a problem.

              Worth also popping the vanos cover off to check there is no oil contamination inside.

              Also check on inlet side for air-leaks - there is a rubber cap underneath the inlet manifold that is prone to splitting.

              HTH

              Comment


              • #8
                When is cold car-all is ok!
                Issue is only on 90 °C
                And only when I switch off hot car(90°C),and ignition on for 1-2 min.
                If I do not turn off the hot car everything is ok!

                Solenoids resistance must be approx. 4ohm !
                Rubber cap bellow ITB is ok!

                Comment

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