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    No spark, tach not moving while cranking

    I've got an '88 325i vert with a no start, no spark issue. I've replaced the following parts: spak plugs and wires, cap and rotor, coil, CPS. I've got 12 volts at the coil with ignition on, and the engine cranks over well, but no spark. Also the tach stays at 0 while cranking. Would this indicate a bad CPS, even though it's a new part? Thanks.

    Sent from my SM-G960U using Tapatalk
    1988 Alpinweiss 325i Convertible

    #2
    At the CPS make sure you're getting 12v and a ground. If you are, crank the car and verify that the CPS is sending a 5v pulse out.
    Originally posted by wholepailofwater
    Q
    :devil:


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

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      #3
      The CPS is registering over 800 ohms, and I think it should be around 540, right?

      Sent from my SM-G960U using Tapatalk
      1988 Alpinweiss 325i Convertible

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        #4
        Originally posted by ryan.of.peachey View Post
        The CPS is registering over 800 ohms, and I think it should be around 540, right?

        Sent from my SM-G960U using Tapatalk
        Yeah an OEM one will read that, but some aftermarket ones I think will read a little higher than that.

        But what I'm saying is verify that you're getting power, ground and signal coming out of the CPS.
        Originally posted by wholepailofwater
        Q
        :devil:


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

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          #5
          I pinned out the DME and I'm getting a signal from the CPS at pins 46 and 47. The only thing that seemed wrong was I couldn't get the main relay to click when I jumped pin 36 to ground. Also the coil main post to 15 is reading close to 7k ohms, so I think the coil may be bad...even though its new..

          Sent from my SM-G960U using Tapatalk
          1988 Alpinweiss 325i Convertible

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            #6
            Originally posted by MrBurgundy View Post
            Yeah an OEM one will read that, but some aftermarket ones I think will read a little higher than that.

            But what I'm saying is verify that you're getting power, ground and signal coming out of the CPS.
            Not sure about you guys in the US, but here in Germany when i was looking for a new CPS, several popped up, a few of them were rated at 800 ohms, some were 550 ohms, pictures of both sensors looked identical but online pics maybe just a sample or incorrect.

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              #7
              Either way I got a new CPS from BMW and it checks out at 530 ohms. Still trying to track down the no spark. Thinking it may be a bad connection to main relay.

              Sent from my SM-G960U using Tapatalk
              1988 Alpinweiss 325i Convertible

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                #8
                Originally posted by ryan.of.peachey View Post
                Either way I got a new CPS from BMW and it checks out at 530 ohms. Still trying to track down the no spark. Thinking it may be a bad connection to main relay.

                Sent from my SM-G960U using Tapatalk
                Best method of testing sensors is to pull the DME pins and to verify that whatever the sensor output is, the DME is getting the same signal.

                Have you tried to swap the DME and ECU relais? If you suspect a loose/bad connection, try to "jiggle" the wires a bit and see if it makes a difference.

                Since you replaced the CPS and Spark Plug wires (which comes with another sensor) are you certain that you did not mix up the connections near the OBD port?

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                  #9
                  Thanks for your reply. I'm certain I got the wires hooked up correctly. I even tested the ECU plug to make sure I'm getting a signal from the CPS to the ECU. I have tried swapping out ECUs also, which didn't have any effect. I have 12 volts at the coil, so I think the ignition switch is good. I replaced the main relay, but I need to do more testing to make sure it's getting power I guess. I had my wife listen for it to click when turning the ignition on and there was no click.

                  Sent from my SM-G960U using Tapatalk
                  1988 Alpinweiss 325i Convertible

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                    #10
                    You're better off putting a finger on the relay.

                    You'll feel the click more than you'll hear it,.
                    Originally posted by wholepailofwater
                    Q
                    :devil:


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

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                      #11
                      Finally got it started. Used some wires to jump the main relay and it fired right up. I guess I got a bad part when I bought the relay...either way a new one is on order from Turner.

                      Sent from my SM-G960U using Tapatalk
                      1988 Alpinweiss 325i Convertible

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                        #12
                        ive got a similar issue, cranks well but no spark but occasionally runs for a couple second and cuts out.

                        im also expecting crank sensor, cam sensor or relay. im using an after market ECU so logged a cranking no start sequence which showed a SYNC error.

                        anyone got main relay PN handy?
                        89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                        new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

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                          #13
                          Here you go...

                          https://www.turnermotorsport.com/p-1...IegaAn8i8P8HAQ

                          Sent from my SM-G960U using Tapatalk
                          1988 Alpinweiss 325i Convertible

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