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    M20 running rich

    My '89 325i is running rich

    so i checked out
    distr. cap + rotor
    air filter
    all OK

    but I saw NGK ZGR5A spark plugs (well known on an M30)
    are they ok for in an M20 ?
    if not causing they a rich running engine ?



    TIA Axl Cohen

    1989 E30 318iS_______________________________1989 E30 325iC M-Technic I
    1997 E36 328iT
    1990 E30 325iT 24v SOLD
    1989 E30 325i 2.7i M-Technic II SOLD

    #2
    Not sure about those spark plugs. I've only used Bosch oems myself. Most postings about spark plugs say the oems are best and to especially avoid the Bosch platinums.

    Check your Bentley manual for troubleshooting a running rich problem. When my car was running rich (resulting in horrible fuel economy) it turned out my Oxygen Sensor. Bought a new one (BMA Autoparts had the best price) and problem solved.

    Comment


      #3
      The first place to check when dealing with a rich running M20 is the coolant temp sensor (not the same as the gauge sender). It's found in the thermostat housing and can be blue or yellow. It has 2 prongs.

      Check it according to the values found in the Bentley when hot and cold. Also check the same value at the ECU end of the harness to make sure that there is no break in the harness. This sensor is the main input for teh ECU to determine the correct fuel mixture.

      Another thing to check is the throttle position switch under the throttle body.

      You should also let us know if it is rich on start-up or when it's warm. The O2 sensor is ignored when the engine is cold so you can eliminate it at first.

      James

      Comment


        #4
        Originally posted by arsevader
        The first place to check when dealing with a rich running M20 is the coolant temp sensor (not the same as the gauge sender). It's found in the thermostat housing and can be blue or yellow. It has 2 prongs.

        Check it according to the values found in the Bentley when hot and cold. Also check the same value at the ECU end of the harness to make sure that there is no break in the harness. This sensor is the main input for teh ECU to determine the correct fuel mixture.

        Another thing to check is the throttle position switch under the throttle body.

        You should also let us know if it is rich on start-up or when it's warm. The O2 sensor is ignored when the engine is cold so you can eliminate it at first.

        James


        It runs horrible when the engine is cold, the first 2-3 mins it smokes, doesn't even pull decent
        When the engine is warmed up a 'bit it'll runs fine and not rich

        so, I think the ECU coolant temp. sensor based on your comment :?

        1989 E30 318iS_______________________________1989 E30 325iC M-Technic I
        1997 E36 328iT
        1990 E30 325iT 24v SOLD
        1989 E30 325i 2.7i M-Technic II SOLD

        Comment


          #5
          Originally posted by BavarianBimmer
          It runs horrible when the engine is cold, the first 2-3 mins it smokes, doesn't even pull decent
          When the engine is warmed up a 'bit it'll runs fine and not rich

          so, I think the ECU coolant temp. sensor based on your comment :?
          I'd bet money on it. As I said before, you should also check the harness. It is notorious for breaking at the sensor connector under the rubber boot.

          James

          Comment


            #6
            Originally posted by arsevader
            I'd bet money on it. As I said before, you should also check the harness. It is notorious for breaking at the sensor connector under the rubber boot.

            James
            Gonna check that tomorrow, thanks for the great help :-D

            how do you mearsure if the wire it's broken?
            I think measure the resistance through the ECU is a bad methode :?
            On the pins from the ECU connector? If so wich pins ?

            TIA Axel Cohen

            1989 E30 318iS_______________________________1989 E30 325iC M-Technic I
            1997 E36 328iT
            1990 E30 325iT 24v SOLD
            1989 E30 325i 2.7i M-Technic II SOLD

            Comment


              #7
              mission accomplished, was a bad contact on the coolant temp sensor

              thanks for the help

              1989 E30 318iS_______________________________1989 E30 325iC M-Technic I
              1997 E36 328iT
              1990 E30 325iT 24v SOLD
              1989 E30 325i 2.7i M-Technic II SOLD

              Comment


                #8
                i really really really like your red 318....

                Comment


                  #9
                  Originally posted by BavarianBimmer
                  mission accomplished, was a bad contact on the coolant temp sensor

                  thanks for the help
                  Awsome. That's great.

                  James

                  Comment


                    #10
                    yep, mine was loose too! Just read this thread, went popped the hood, checked the sensor, and it runs very good now!!!

                    Comment

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