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Engine revs itself to redline - help!

Discussion in 'Mk2 Ibiza/Cordoba FAQ's (6K) 1993-1999' started by Vedad1944, Feb 18, 2018.

  1. Vedad1944

    Vedad1944 Active Member

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    (Seat Ibiza 1995 6K 1.4 ABD)
    This has happened before, and I've replaced the idle air control valve 051 133 031 with a second hand one about two and a half months ago, it was actually the fourth one that worked, we unhooked the battery overnight, and let it learn to idle tomorrow morning. It was way better than before, not to mention the self-destruct mode the engine apparently initiates has actually stopped.

    It happened to me again today and I don't know whether to replace it with a new part or remove it altogether and make it cable operated.

    - Can an IACV even rev an engine to redline?

    I rely on it every day, and use it for up to 20 miles per day of city driving, and it is what it is, an old car, and if I could I'd just get rid of the thing, but due to my current situation I can only afford cheap/DIY fixes.

    I've seen a brand new BOSCH IACV which is expensive, but there's also one made by "ERA Automotive parts" - it's 80% cheaper.

    Can anyone give me some advice on how to proceed properly? I am just so paranoid now, that I think not even new ones would solve the problem. Maybe it's not that part, maybe there's something else?

    Thank you everyone in advance!
     
  2. Vedad1944

    Vedad1944 Active Member

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    Update: I took a 12 volt power supply and connected it to the pins of the old actuator and it works!
    So, there's something else in play here. Maybe the injection unit itself is dirty or something and it gets stuck?
    I'm gonna try and think of something.
     
  3. Vedad1944

    Vedad1944 Active Member

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    Update: I was at the mechanic's, I've replaced the oil (it was due in 600mi so I figured why not), and filters, then turned to a strange yellow paste coming from the PCV valve. The mechanic says it's just condensation, and that happens during cold/humid weather and needs to be cleaned when present.
    Indeed during hotter weather it was not present.

    Anyway, moved onto the self revving thing, the car runs fine at the moment and I haven't had a single hiccup. The vacuum hoses are fine and in good condition, the sensor 4-pin plug has no moisture coming to it and has no oxidation traces.

    On the other hand, I've had my car stall often in humid weather from the day I bought it 3 years ago. We thought it was the ignition, but everything under the bonnet was as dry as bone.

    Then I asked the mechanic to show me where the ECU is.

    Holy sh**, why is the ECU so exposed??? It's in between the bonnet and the windscreen underneath some plastic cover the thickness of a human hair! What the hell VW?
    The ECU was wet all over, and in covered in all sorts of dirt!
    We cleaned all the crud out, and I'm gonna wait for a warmer, drier day and try to protect the ECU as much as possible.

    Also, my battery light stopped showing up on the dash, we tried disconnecting the single pin from the alternator but it still didn't appear.
    Could the ECU be the culprit?
     
  4. Vedad1944

    Vedad1944 Active Member

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    I found an ancient (2003) page with info on how some guy adjusted his throttle valve positioner.
    It seems that there's a potentiometer somewhere within the injection unit, and it dictates at what position the butterfly valve is to the ECU.
    I wish I could measure the output voltage from the ECU ports somehow and see what the ECU is missing.
     
  5. Ningyupowadat

    Ningyupowadat Active Member

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    Hey man did you ever do anything to protect the ECU?

    IV had this problem with stalling and misfiring on 2 mk2 Ibiza's and I just run the car for 10 minutes up to operating temperature every morning from September to may to avoid this. It's fine in summer.

    As for the yellow sludge. IV almost completely eliminated this by only using fully synthetic oil.
     

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