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m20b25 not running right.. thoughts?

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    m20b25 not running right.. thoughts?

    Recently acquired an 89 325is that had been parked for 6 months after a front end fender bender. Previous owner parked the car because the front end damaged ruined the water pump.

    We've since replaced the water pump and cranked the car. Problem now is it runs like total shit. Idles VERY rough, and with the pedal floored the car won't do more than 1000rpms. The motor actually seems to run smoother, and with higher rpms, at idle than it does with pressure on the gas pedal.

    The computer is throwing no codes. We've swapped in a known working MAF with no change. Any thoughts?

    #2
    maybe damaged more than the water pump? timing belt? crank pulley? end of the crank bent? what other damage was done to the car? have pics of the damage done?

    aka need more info.

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      #3
      Check the CPS wire since it runs next to the water pump.
      Did you do the timing belt at the same time? Should have if you didnt.
      Do the stomp test and see if it comes back with any codes.
      Last edited by e30this; 02-09-2009, 06:48 PM.

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        #4
        what do the spark plugs look like?
        Build thread

        Bimmerlabs

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          #5
          Spark plugs are new... stomp test reveals no codes.... timing belt was changed when we did the water pump. Also, see no frays in the CPS wire.

          No significant damage to the front end. The impact apparently was just hard enough to push the radiator into the fan.

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            #6
            sounds like a misfire (smoother at higher RPMs)... check the ignition system
            1989 cirrisblau-metallic 325i

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              #7
              Update...

              ECU swapped
              TPS swapped
              MAF swapped
              New fuel filter
              Confirmed spark to all 6 plugs
              Timing is spot on
              Engine throws no codes

              We've looked the CPS over, is there an easy way to confirm it works? Any other thoughts or ideas? What would a faulty O2 sensor act like?

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                #8
                fuel delivery?

                edit: didnt see that you had replaced the fuel filter, but possibly clogged lines?

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                I stand up, pull my dick out, and asked my gf to give me some noggin... Well, she starts laughing at me and I freaked out and ran off and locked myself in a bedroom.
                1989 325i - Project/weekend driver
                2002 325i - DD
                2005 Suzuki SV650 - Toy

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