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    another M50 wont start thread

    hey guys,
    im at the finishing stages of my m50 swap and it wont start.

    Background:
    Engine is a '92 non vanos out of a 325. the engine came out of my brothers car which ran great until he started getting low compression. Turns out one of the valves had hit a piston so there was a crack in the piston and a bent valve. We had another m50 lying around with unknown history so i took the bottom end off that and used the head off my brothers engine. lapped the valves and replaced 2 valves. put in new seals and gaskets and put it all together. I did not have the timing tools but i tensioned the chain with the origional tensioner, placed cylinder 1 at TDC, and the cams pointing at each other with the square ends perfectly perpendicular.

    engine turns over smoothly without the plugs in. i have fuel and spark. all ignition coils have been tested individualy and are functional. But when i try to turn it over with the plugs in, it chugs and sputters and backfires but doesnt want to go. it had a few close calls where it fired for half a second then died. it doenst sund healthy and doesnt crank smoothly with the plugs in.

    the wiring harness is also off my brothers car which was functional and he labeled everything before giving it to me.
    im using the akg harness adapter
    its got a new crank sensor

    im starting to think its a timing issue? would a bad cam sensor cause this?

    thoughts?

    thanks

    #2
    Did you position the crank trigger wheel over the alignment pin when you put it back on?

    Comment


      #3
      Originally posted by Janderson View Post
      Did you position the crank trigger wheel over the alignment pin when you put it back on?
      can you clarify this? where is the alignment pin?

      Comment


        #4
        alignment pin is on the crank snout. Should be the 6 evenly spaced bolt holes and one smaller guide pin hole.
        '87 325ic, powered by S50.

        Comment


          #5
          ahh i see so its possible when i put the crank wheel on the block that i didnt align it properly which is causing these symptoms.

          This makes sense since the CPS can't figure out where the crank is at...

          Ill double check this

          Comment


            #6
            same thing happened to matt it was the crank wheel
            Originally posted by bmwm42
            PNW vulture pm me for parts
            Strategic nw e30 command

            Comment


              #7
              You guys are awesome!

              Crank wheel wasn't on the aligment pin as you stated, so fixed that and she fired right up!

              Ill post a video a little later

              Comment


                #8
                Excellent!

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