struikie - Audi 80 B4 quattro project

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  • struikie
    S2Forum Addict
    • May 2019
    • 314
    • Country: Netherlands

    #271
    My starter motor (solenoid) decided to slowly die. Got a used one
    and swapped it in today.



    Engine has been lumpy for a while. Can't find the cause.
    Swapped injectors (refurbished)
    Checked plugs - all look fine
    New leads (I had broken one)
    New coilpack
    New cam sensor
    New crank sensor (also because of the new seal)
    Vacuum lines hold vacuum
    Set FPR at 4bar with no vacuum attached
    Checked compression - all get up to 12 bar

    Pulled the vacuum line off the FPR. When blocking this
    off I can hear a leak. With the line open I cannot hear
    that same hiss. I'll pull the intake next weekend and see what
    I will find.

    JW
    Last edited by struikie; 13 September 2026, 11:45.
    | project | 1993 Audi 80 VR6 turbo quattro |
    | daily | 2018 BMW G31 530d | 345bhp 770Nm |

    Comment

    • struikie
      S2Forum Addict
      • May 2019
      • 314
      • Country: Netherlands

      #272
      Removed the intake manifold and took it apart.
      Both the plastic top and bottom part have a rubber track
      that is meant to seal to the aluminum middle part. Both were really
      hard and flat. Dug the rubber out and put a bead of liquid gasket
      in. Reassembled and let it sit for a day.

      While the intake was off I saw that the knock sensors were in bad shape.
      Replaced both. Also replaced the ISV as it wasn't looking too fresh.

      On first start it idled at 1300rpm. A little throttle blip made it hunt.
      Second start all was well. It took the ecu a bit of time to set the ISV
      correctly. It hasn't been running a nice as this for a long time.
      Smoother and with more torque at low rpm.

      Next I'll have a shop fix the leaks in the exhaust and have them
      reconfigure it a bit to remove a the tension when it is all together.
      After that:
      - an MOT in November
      - refurbish the front subframe
      - have a proper alignment done

      I'll also be looking into starting to have the roof liner retrimmed in black.

      JW
      | project | 1993 Audi 80 VR6 turbo quattro |
      | daily | 2018 BMW G31 530d | 345bhp 770Nm |

      Comment

      • struikie
        S2Forum Addict
        • May 2019
        • 314
        • Country: Netherlands

        #273
        There is still something not quite right with engine. When the battery has
        been disconnected, the engine runs nice with good torque from low revs.
        As time goes by, it starts to be jerky at low revs. I guess it is making
        adaptions based on sensor readings. (tried 2 different ecu's)
        Perhaps I need to try 2 new lambda's?

        JW
        | project | 1993 Audi 80 VR6 turbo quattro |
        | daily | 2018 BMW G31 530d | 345bhp 770Nm |

        Comment

        • RedV6
          S2Forum Fanatic
          • Jun 2026
          • 63
          • Country: Scotland

          #274
          Is the alternator charging correctly?
          A dodgy voltage regulator in the alternator giving lower or higher output or irregular output can play havoc with the inputs to the ecu from the various sensors!

          Comment

          • struikie
            S2Forum Addict
            • May 2019
            • 314
            • Country: Netherlands

            #275
            I'll have a look at the voltage.

            JW
            | project | 1993 Audi 80 VR6 turbo quattro |
            | daily | 2018 BMW G31 530d | 345bhp 770Nm |

            Comment

            • struikie
              S2Forum Addict
              • May 2019
              • 314
              • Country: Netherlands

              #276
              Voltage looks good. No fluctuations.

              JW
              | project | 1993 Audi 80 VR6 turbo quattro |
              | daily | 2018 BMW G31 530d | 345bhp 770Nm |

              Comment

              • RedV6
                S2Forum Fanatic
                • Jun 2026
                • 63
                • Country: Scotland

                #277
                Ah. Pity! That might have been an easy solution, at least thats one thing eliminated!

                Comment

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