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AFM connector issue.

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  • AFM connector issue.

    Hi, I’ve been having an intermittent contact issue with my AFM connector for almost 20 years. The connector was rebuilt once with no improvement. The AFM was changed with no improvement.

    The car typically runs fine. But if the AFM connector is ever unplugged when I’m working on the car, the issue crops up after it is replugged. The car won’t rev past 2000rpm sometimes, idle sometimes. A shot of contact cleaner followed by a series plug/unplug Fixes it until the next oil change or the next time I have to unplug it for any reason.

    Until today. On a 25 mile drive, I had to pull over 3 times as the engine refused to rev past idle. The first time I needed contact cleaner. The other 2 times were fixed with just unplugging and replugging. I had just done an oil change a month ago and did my “ usual rituals” with the connector and went for a 40 mile drive with no incident. Then the car sat for a month as life got busy… and other cars needed their turn.

    Attached are photos. There is no corrosion. The gap between the metal contacts seems normal to me. Any ideas? Should I rebuild it again?
    thank you,

  • #2
    I’m getting an “invalid image geometry “ error when trying to attach a picture.


    • #3
      Originally posted by Narayan3 View Post
      I’m getting an “invalid image geometry “ error when trying to attach a picture.
      Unfortunately, it has been that way for a year or two. I am guessing that it probably has something to do with the expense of maintaining this forum and the few very good guys that manage it on their own time.


      • #4
        The only person who can fix it is Magnus. We moderators don't have the access needed.


        • #5
          I don't think it's the connection but the wiring loom itself.
          If you wrench yourself you could get the 5 pin connector off ebay (better new, it's a tyco junior timer connector) and wire it to the ecu temporarily by just laying the wires around the outside and into the cabin via passenger door.
          You can either open up the ecu, feed the 4 wires in through the plugged opening in the lid and solder the wires directly onto the appropriate legs of the ecu connector to the pcb.
          Alternatively you can disassemble the connector and 'backprobe' the appropriate terminals.
          3rd option is monitor the input into the ecu by hooking up a (analogue if possible) voltage meter to the legs inside the ecu and watch the gauge as soon as the problem occurs to identify which wire is broken inside. Mind that you must check the ground wire first by connecting your voltmeter to terminal 6 and 31 (=+12V ignition on).

          The pinouts of the afm connector is:
          1 grey-violet to terminal 22 on the ECU (=air temp signal)
          2 grey-yellow to term 7 on the ecu (=AFM air flow signal)
          3 grey-white to term 9 on the ecu (= +5V to air flow potentiomenter)
          4 grey-green to term 6 on the ecu (= ground to AFM for both air temp sensor and air flow potentiometer)