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    #1

    No spark, extensive testing

    I am not getting any spark in my 1988 325is. I was driving down a bumpy road. Nothing big, no scrapes, just a lot of small bumps (may or may not be relevant). The car drove fine for about 300 yards and the engine started cutting out completely until it just stopped running. It sounded as if it was sputtering, which initially lead me to believe my issue was fuel related. The car would start for a short time after it died but only for a second before it would eventually die again. This happened about 5 more times until I eventually could not get the car to start at all.
    Once the car was towed to my garage, I soon realized that I am not getting any spark.

    So, I did a little testing....

    I started by checking for spark by connecting a spark plug directly to the distributor wire that runs the the distributor. I connected the positive end of a jumper cable to the plug, and the other end to ground. I get one fleeting spark when I turn the ignition on, but no spark when cranking.

    I replaced the DME with a known good one.
    I tested the coil, it is within spec for resistance per the Bentley (1&15 gets .82 ohms, 4&1 get 5200 ohms)
    Swapped a good known coil
    Check the resistance of the coil wire to distributor (within spec)
    Check power to the coil, I get 12v on each pin with ignition on.
    Checked c101 connector 7, I am getting 12v there, I also have continuity between c101 pin 7 and pin 15 on the coil.

    I did a DME pinout, it all was within spec. I can hear the injectors, main relay, and the fuel pump will pump fuel, I removed the fuel hose from the rail to verify.



    I'm pretty stumped, so any help would be greatly appreciated.
    1988 325is

    Tags: None
    #2
    Charge the battery brah.




    Bump, so I'm actually the one who has been helping Max do the troubleshooting, I am stumped real good.

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      #3
      Bump
      1988 325is

      Comment

        #4
        Bump
        1988 325is

        Comment

          #5
          Extensive testing fail for not checking the cps. You lost me on your spark plug testing procedure.

          Comment

            #6
            Originally posted by uturn View Post
            Extensive testing fail for not checking the cps. You lost me on your spark plug testing procedure.
            Weird, I though it was listed. The cps was checked as was within spec. No as far as the spark plug test, was there something you would have done differently?
            1988 325is

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              #7
              Possible solution

              I had a similar situation and went through all the troubleshooting and parts replacement before I got to the solution. I had posted the result:
              http://www.r3vlimited.com/board/showthread.php?t=326304

              Comment

                #8
                Originally posted by DigginMyE30 View Post
                I had a similar situation and went through all the troubleshooting and parts replacement before I got to the solution. I had posted the result:
                http://www.r3vlimited.com/board/showthread.php?t=326304
                Awesome! Thank you.
                1988 325is

                Comment

                  #9
                  Mate, this is from a PM with the wizard who helped me.

                  Originally Posted by STIG

                  Hey mate, you helped me out a great deal last time with my no spark issue.

                  My friend is having a very similar issue but I can't seem to find any issues anywhere but the fact that he doesn't have spark. The thread is hear.

                  In a nut shell, I've done the bently test sheet that you gave me last time and everything tested to spec.

                  The CPS is also within spec Ohms wise. I've tried my DME in his car and it doesn't resolve the issue.

                  The most interesting part to me is that when you turn the key to on, a grounded spark pug gets one fleeting spark, I think this is key to the issue, unless this is normal.

                  I've tried a known working coil. The coil, and spark plug wire both test within spec.

                  We get power to the right pin (7) at c101, and continuity between the c101 pin and the coil. Coil tests fine per Bentley for voltage at pins, and resistance.

                  At this point I'm thinking maybe the issue is we aren't getting the right signal from CPS, or some other issue like that, it seems as if the car should get spark since all the electrical tests fine.

                  Do you think testing with a scope is the next step?


                  I really appreciate the help, and time reading and trouble shooting with me in the past, and this time.

                  Mike

                  first off a scope is nice but not necessary yet, does the fuel pump run while your cranking ? this can be used as a CPS signal test as the pump wont run (commanded by ECU ) unless it see's cranking signal from CPS

                  second have you tried the test light flashing on the coil neg terminal to see if ECU is trying to control coil ?

                  as far as the one spark at key on that seems unusual ,almost wonder if the signal wire is shorted to ground or there is a problem with the ECU , does it do that with your EU in the car?

                  did you read thru that old post on your car to get ideas on other test we did to resolve your problem? which turned out to be an issue at the C101 wasnt it?

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