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Its driving me nuts, Need Help!a

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    Its driving me nuts, Need Help!a

    Hi all,

    been a proud e30 owner (various models) for over 25 years. My latest though is driving nuts.

    The car is a 1988 320i convertible automatic. I recently finished restoring the car and found a leak from the auto box after it had been rebuilt. So I took it back to the shop to have the leak fixed.

    They fixed the leak, but as I was driving the car back home, it started loosing power and hesitating and eventually the more I depressed the accelerator the more it hesitated (will not rev) and started back firing and then eventually stalled.

    I then put the car in Park, it started and idled perfectly, I put it in drive and start driving only to act up again. Turned the car off and back on, it happily idles and revs to redline in Park and Neutral, as soon as I engage any gear, drive it for a few meters, then put it back in Park or Neutral and try rev it, its starts to hesitate again. The whole cycle is reproducible and it does not matter if the car is hot or cold.

    I called the shop and they said it cannot be the autobox and so I began the journey to date.

    The car already had a top end rebuild and the following items were new; Timing belt, water pump, spark plugs, leads, distributor cap, crank position sensor, fuel pump, coolant temp sensor.

    Airflow meter, ECU and coil were swapped out one at a time but the car behaves exactly the same. TPS was checked with a multimeter and both idle position and WOT register perfectly.

    Every electrical plug in the engine bay has been checked, sprayed with electrical contact cleaner, and wiggled while the car is running, but nothing to indicate they are at fault.

    The bizarre thing is the car revs to redline in Park or Neutral, as soon as a gear is engaged and a car is driven only a few feet, it starts to act up even in Neutral or Park.

    Does anyone know if there is any electrical anything related to the Auto Trans in an E30 that would cause this?

    #2
    Check your CPS, fuel pressure and C101 connector.

    The CPS is often forgotten after doing a t belt and isn't properly tucked into the clips. It's possible its frayed and causing ignition loss. As for the park and neutral thing, sometimes these problems are only shown under a load, which is what's happening with you.

    Also, you say the fuel pump is new, but you have to actually watch the pressure to eliminate that possibility.

    My money is on a fuel issue
    Originally posted by wholepailofwater
    Q
    :devil:


    WTB: Dove Grey e36 Front Door Panels (2 door)

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      #3
      Hey MrBugundy, the CPS is brand new, c101 is good, however, I have not checked fuel pressure...

      Comment


        #4
        I vote for a fuel pressure check also.

        Comment


          #5
          I agree that it does sound fuel related and agree with those who mention a pressure test, however in this case I would also recommend a fuel delivery rate test as well.

          I have seen fuel pumps deliver the pressure but not produce the volume needed to run properly under load...and it does not necessarily mean the pump is bad, the fuel filter could be plugged, the pump pick-up screen could be partially blocked, etc.

          The pump should deliver 875mL (30oz) in 30 seconds. To test, remove the fuel return line from the bottom of the fuel pressure regulator, connect a length of hose and route it into a suitable container, remove the fuel pump relay and jumper pins 30 and 87 (ideally using a switched + fused lead).

          Also remember that a static fuel pressure test should deliver right around the rating of the fuel pressure regulator (2.5 or 3.0 bar), if you do the test with the engine idling and the vacuum line connected, it will read slightly lower than the rating, remove the vacuum line and it should rise to the regulator rating.

          Above all, be safe, do this on a cold engine and have an extinguisher handy.

          Comment


            #6
            Buy a meter of fuel hose, a tee, and some zip ties.

            Zip tie the fuel pressure gauge to the windshield wiper and
            watch it drop as you load the engine.

            Everything from a bad pump to junk in the tank can cause bogging under load,
            and a loaded fuel pressure test finds them all. Then you get to narrow it down.

            the CPS is brand new,
            these days, that makes me suspect it.


            t
            now, sometimes I just mess with people. It's more entertaining that way. george graves

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