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E30 M60B40 crankshaft position sensor problem

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    E30 M60B40 crankshaft position sensor problem

    Hello,

    My name is Tom and i am new here :)
    I am struggling with the electrical problem with my project. We cannot start the engine because there is no 5V AC voltage in crankshaft position sensor connection.. The white relay also works when the ignition is on. We also have tried to replace several CPS sensors. All of them read 500ohm resistace.

    As i understand, if there's no 5V AC voltage, the engine wont start because the CPS does not give the spark or open the injectors?
    Where whould we search for the problem ?


    #2
    Pics? Factory sensor?
    If the sensor is good and it's getting the right power, then installation, like excessive gap to the wheel, could be a problem.

    Comment


      #3
      Factory sensor. Gap is OK. If you connect the crankshaft position sensor to camshaft position sensor the engine starts.

      Problem that there is no 5V AC voltage in pins for the connector on the drivers side. Next thing that we will try is to replace the engine harness with a 404 non ews one, and see if it will start
      Last edited by backa; 12-04-2017, 07:23 AM.

      Comment


        #4
        Isn't the m60b40 CPS just an inductive type sensor? As in, it generates voltage on it's own via the internal coil, it doesn't receive voltage from the DME. One pin should be the A/C voltage signal to the DME, one pin should be ground from DME, the last should be ground shielding to chassis ground.

        I don't understand what you're saying about plugging the crank sensor into the cam sensor. Are you saying you took the engine harness crank sensor connector, and plugged it into the camshaft sensor, and the engine started, and continued to run? That would really surprise me, but if that's the case, that proves the harness and DME are good, and your problem is with the crank sensor mounting and/or crank pulley alignment. But I find that hard to believe... The crank and cam timing wheels are nothing alike, much less timed the same, on top of the fact that the cam is spinning 1/2 as fast as the crank.
        85 325e m60b44 6 speed / 89 535i
        e30 restoration and V8 swap
        24 Hours of Lemons e30 build

        Comment


          #5
          Originally posted by JGood View Post
          Isn't the m60b40 CPS just an inductive type sensor? As in, it generates voltage on it's own via the internal coil, it doesn't receive voltage from the DME. One pin should be the A/C voltage signal to the DME, one pin should be ground from DME, the last should be ground shielding to chassis ground.

          I don't understand what you're saying about plugging the crank sensor into the cam sensor. Are you saying you took the engine harness crank sensor connector, and plugged it into the camshaft sensor, and the engine started, and continued to run? That would really surprise me, but if that's the case, that proves the harness and DME are good, and your problem is with the crank sensor mounting and/or crank pulley alignment. But I find that hard to believe... The crank and cam timing wheels are nothing alike, much less timed the same, on top of the fact that the cam is spinning 1/2 as fast as the crank.

          Hello, thanks for your answer.
          When I am plugging the crankshaft position SENSOR to camshaft position sensor CONNECTOR(passenger side) the car starts right away and is running on idle fine. There is no 5V AC voltage for the crankshaft sensor connector pin(drivers side), so the car does not start when it should.
          We will try to replace the engine harness and see if it will solve the problem.

          sorry for my bad english, if you still dont understand me i will try to post up some pictures with explanation :)

          Comment


            #6
            Well, like I said, the crank sensor isn't supposed to receive 5 volts from the DME on the m60b40, as it's an inductive sensor. It generates A/C voltage as the trigger wheel spins, and sends it to the DME.

            You're chasing a problem that doesn't exist. I'd think the fact that the car runs fine with the crank sensor plugged into the passenger side connector would clue you in to the fact that that is how it's supposed to be. The crank position sensor connector is on the passenger side of the harness, and the cam position sensor wire crosses under the throttle body over to the driver side of the harness.

            There's nothing wrong, you just got the plugs locations confused.
            85 325e m60b44 6 speed / 89 535i
            e30 restoration and V8 swap
            24 Hours of Lemons e30 build

            Comment


              #7
              Originally posted by JGood View Post
              Well, like I said, the crank sensor isn't supposed to receive 5 volts from the DME on the m60b40, as it's an inductive sensor. It generates A/C voltage as the trigger wheel spins, and sends it to the DME.

              You're chasing a problem that doesn't exist. I'd think the fact that the car runs fine with the crank sensor plugged into the passenger side connector would clue you in to the fact that that is how it's supposed to be. The crank position sensor connector is on the passenger side of the harness, and the cam position sensor wire crosses under the throttle body over to the driver side of the harness.

              There's nothing wrong, you just got the plugs locations confused.


              Sooo just to make things clear, the CRANKSHAFT position sensor on m60b40 plugs into passenger side connector, and the CAMSHAFT position sensor plugs into drivers side connector ?

              Comment


                #8
                Correct. If you are in front of the car, looking at the engine, the crank sensor goes onto the left side connector. The cam sensor crosses over to the other side of the engine (under the throttle body) to the right side connector.
                85 325e m60b44 6 speed / 89 535i
                e30 restoration and V8 swap
                24 Hours of Lemons e30 build

                Comment


                  #9
                  Originally posted by JGood View Post
                  Correct. If you are in front of the car, looking at the engine, the crank sensor goes onto the left side connector. The cam sensor crosses over to the other side of the engine (under the throttle body) to the right side connector.
                  The left side of the car has the left turn signal on it. End of discussion.

                  This "left when you're looking at the engine" BS is confusing and counter productive.

                  Comment


                    #10
                    Well, i think someone messed up the sensors or put not the original ones, thats why i couldnt find out witch goes where by the lenght of the sensor cable. Kinda awkward situation though :D
                    Thank you guys so much!

                    By the way here' my drift car i built by myself in 3 years of progress :)
                    Attached Files

                    Comment


                      #11
                      Originally posted by The Dark Side of Will View Post
                      The left side of the car has the left turn signal on it. End of discussion.

                      This "left when you're looking at the engine" BS is confusing and counter productive.
                      K



                      Originally posted by backa View Post
                      By the way here' my drift car i built by myself in 3 years of progress
                      Nice! Looks like a tubular front end, were you able to use the e34 radiator with that setup? Any plans to get rid of the ASC throttle body? Doesn't seem like it would clear the hood.
                      85 325e m60b44 6 speed / 89 535i
                      e30 restoration and V8 swap
                      24 Hours of Lemons e30 build

                      Comment


                        #12
                        Originally posted by JGood View Post
                        K





                        Nice! Looks like a tubular front end, were you able to use the e34 radiator with that setup? Any plans to get rid of the ASC throttle body? Doesn't seem like it would clear the hood.

                        Hey, yes its a tubular end, i will currently try to run with e46 rad+eletrical cooling fan. But the bigger rad also fits nicely :)
                        The ASC throttle body inside is deleted. Only kept the elbow for now. I will be replacing it with silicone elbow for cooler look in future :) The hood closes perfectly :)

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