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  • Plese help ABS Question.

    Hi all,
    My car is 90 and this ABS issue drives me crazy! ! !

    Ok hear is the symptom.

    1. When I am driving and apply light brakes to stop the car the ABS start working hrrrrrrrr and pedal is hard?. When the car is full on stop the pedal goes soft as it should. I changed the brake booster with the pump and still the same.

    2. When I start the car the ABS light is off when I start cruising after 10 comes ON. ? Some times is on from start.

    Possible issue???

    ABS Sensors ?
    ABS Unit ?
    ABS Relay, if yes which one ?

    Thank you guys.
    Anri
    Last edited by First E30 M3; 04-13-2010, 05:03 PM.
    sigpic

    - 1990 E30 M3 DS Shwartz S38-B36 (3.6) Sold ! But never forgotten.
    - 1990 E30 M3 DS Euro S38-B38 3.8 340hp. I promise, I will hide the 2 cyl under the dash which "Engine King". Mr. Paul Rosche took away to make the S14...
    - 1988 E24 M6 Shwartz/Track Toy S38-B36 Goal is close to 50/50 I pushed the engine almost 15 inches for weight distribution will see...
    - 1988 E24 M6 Shwartz/Natur, Daily driver.
    - S38 is an addiction, enthusiastic manner and the perfect match for my E30 M3.

  • #2
    Originally posted by First E30 M3 View Post
    Hi all,
    My car is 90 and this ABS issue drives me crazy! ! !

    Ok hear is the symptom.

    1. When I am driving and apply light brakes to stop the car the ABS start working hrrrrrrrr and pedal is hard?. When the car is full on stop the pedal goes soft as it should. I changed the brake booster with the pump and still the same.

    2. When I start the car the ABS light is off when I start cruising after 10 comes ON. ? Some times is on from start.

    Possible issue???

    ABS Sensors ?
    ABS Unit ?
    ABS Relay, if yes which one ?

    Thank you guys.
    Anri
    so you listed all the options already. Now go and check them.


    Goodbye M3, you served me well.

    Comment


    • #3
      ABS sensors...check them
      '88 Sep 03,87 Zinno/Natur 2.5L--the queen
      '90 White/Natur 2.3L---the weekend
      '14 GT-R Red/Black ohhh..yeah!!!
      '09 E82 135i Crimson Red/ Black w/M-Tech goodies--sold
      '94 11/93 AW III 525i M50/S50 cams/5 speed swap--sold
      '11 Nissan Rogue White/Gray
      '89 Wrangler 4.2L 4x4 5 speed
      '66 VW Beetle

      Comment


      • #4
        I don't understand your description but, if you are getting a pulsation from the pedal when you hit the brake pedal, then your ABS sensors and ABS pump might be ok.
        If a wheel speed sensor and or the ABS ECU is bad, the ABS pump is deactivated. Hence I'm not getting the "Rrrr" bit.
        It is possible that you have a smallish grounding of one of the sensor harnesses, so check for a damaged harness sheath under the rear seat at each side. Sometimes the rear seat squab metal braces can abrade the harness.
        The ABS relay is incorporated in the pump chassis for late M3s. Pop the plastic cover on the pump and look for any scorch marks on the top of the pump.

        m

        Comment


        • #5
          Thanks you guys.

          Uwe I did NOT change anything yet.
          That was just my guess what could be.

          I try this morning to Disconnect the ABS ECU for about 5 mins and plug it back and the system worked perfect for about 10mins and then got bad again.

          OK I will check the ABS sensors. Open and clean them up from dust or possible rust ? Will that be ok or changed them ?

          Mark, the "hrrrrrr" is the pulsing pedal at light braking. Sorry for my language.

          Anri
          Last edited by First E30 M3; 04-14-2010, 02:20 AM.
          sigpic

          - 1990 E30 M3 DS Shwartz S38-B36 (3.6) Sold ! But never forgotten.
          - 1990 E30 M3 DS Euro S38-B38 3.8 340hp. I promise, I will hide the 2 cyl under the dash which "Engine King". Mr. Paul Rosche took away to make the S14...
          - 1988 E24 M6 Shwartz/Track Toy S38-B36 Goal is close to 50/50 I pushed the engine almost 15 inches for weight distribution will see...
          - 1988 E24 M6 Shwartz/Natur, Daily driver.
          - S38 is an addiction, enthusiastic manner and the perfect match for my E30 M3.

          Comment


          • #6
            Had this happen to me on two different cars. Each one had a bad ABS sensor. Disconnect them and measure resistance across the pins. It should be somewhere around 900 to 1K Ohms.
            Ron ///Man

            • '91 Gr-A Former CiBiEmme / Ravaglia - Sold
            • '90 M3 Faux EVOII Alpineweiss 36K Orig Owner - The Queen
            • '91 M3 Faux EVO III Brilliantrot Euro Driveline - The Rocket
            • '91 M3 Faux Gr-A Club Racer DM - The Alter EGO
            • '89 M3 M3T / ITR Club Racer
            • '94 Spec E36 - Eh....
            • '09 M3 - Tarmac Terrorist
            • '04 330Xi Sport 6 Speed - Snowmobile
            • '07 530 Xi - Highway Star
            • http://www.imwcarparts.com/e30-m3-parts.htm


            Comment


            • #7
              Thanks,

              Seems like I will start diagnose the system first with the simple things.

              Will start checking the Sensors for the correct Ohms and continue.

              Thanks
              Anri
              sigpic

              - 1990 E30 M3 DS Shwartz S38-B36 (3.6) Sold ! But never forgotten.
              - 1990 E30 M3 DS Euro S38-B38 3.8 340hp. I promise, I will hide the 2 cyl under the dash which "Engine King". Mr. Paul Rosche took away to make the S14...
              - 1988 E24 M6 Shwartz/Track Toy S38-B36 Goal is close to 50/50 I pushed the engine almost 15 inches for weight distribution will see...
              - 1988 E24 M6 Shwartz/Natur, Daily driver.
              - S38 is an addiction, enthusiastic manner and the perfect match for my E30 M3.

              Comment


              • #8
                Originally posted by First E30 M3 View Post
                Thanks,

                Seems like I will start diagnose the system first with the simple things.

                Will start checking the Sensors for the correct Ohms and continue.

                Thanks
                Anri
                If you have been using metallic content brake pads the trigger wheels and sensor points could have metal particles contaminating the system.

                m

                Comment


                • #9
                  Even if all abs sensors pass the resistance test, you may still have a bad one. The ONLY way to really test the sensor is to set a multimeter to the alternating voltage setting, rotate the wheel by hand and then look for large differences in value.

                  A good abs sensor should easily reach 3v output turning wheel by hand. A bad one will be much less (e.g. Less than 1v, often an order of magnitude less).

                  Comment


                  • #10
                    Thanks you guys.

                    Over the weekend will start diagnose the system.
                    sigpic

                    - 1990 E30 M3 DS Shwartz S38-B36 (3.6) Sold ! But never forgotten.
                    - 1990 E30 M3 DS Euro S38-B38 3.8 340hp. I promise, I will hide the 2 cyl under the dash which "Engine King". Mr. Paul Rosche took away to make the S14...
                    - 1988 E24 M6 Shwartz/Track Toy S38-B36 Goal is close to 50/50 I pushed the engine almost 15 inches for weight distribution will see...
                    - 1988 E24 M6 Shwartz/Natur, Daily driver.
                    - S38 is an addiction, enthusiastic manner and the perfect match for my E30 M3.

                    Comment


                    • #11
                      i doubt its a sensor issue.

                      Comment


                      • #12
                        Have you changed your bearings lately??
                        My experience: I had a mechanic swap my units for the cheaper HD e28 M5 units and they left one of the rings of the M5 on it, sending me into an intersection... Rather than risk my ///M I've disconnected the ABS computer 3.5 yrs. ago and still have it in a box. But I had similar symptoms to what you're describing and it was the sensors, so I replaced the bearings, sensor rings, sensors... still don't trust the ABS so it's still in a box.
                        Rich!

                        Comment

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