MK2 8V Digifant acting strange

Discussion in '8-valve' started by timms, Mar 2, 2015.

  1. timms

    timms New Member

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    Hello, really need help from people with more knowledge than me!

    Back story....

    I took my 1990 mk2 GTI for an MOT, She failed on emissions by quite a bit :-( I was told by the garage to change the plugs, the air filter, chuck some emissions stuff in the fuel and give her a good thrash down the motorway to get her through. After doing this it still failed! the garage said they would adjust the Mass air flow meter and throttle body air/fuel screw to get it too pass. After an hour of fiddling the MOT tester came back and said with a grin its passed! brilliant I thought. I got in the car pressed the accelerator and Nothing.... no revs, no movement it just sat there and ticked over! the garage said leave it with them, they'd put the setting back to how they were before the MOT and it would be fine. A weekend passed and I had a phone call to say the Mass air flow meter might be broken and could I source a replacement for them. I managed to get a guaranteed working one but no change still the same symptoms. The garage said they would do a few more checks for me and let me know what was wrong with her. A week passed and another call... the car now wouldn't start! they said they had checked the air flow meter (all good) checked timing (all good) checked the throttle body (all good) fuel pump and fuel pressure (all good) Dizzy, HT leads, Coil (were ok) Compression (all good) they said "shes getting fuel and a spark she should start". They then said they could get her to start but it involved pulling fuse 17 out whilst turning it over and then pushing it back in about 10 times and hey presto it starts and ticks over! but doesn't rev! I left it with them for another week and then another call... they said they had spent all the free time they could on her and if i wanted them to continue it would cost me. so, I had her towed home.

    What I have done....

    I went back over and re checked everything they had, all is as they said, all works or so it seems!, I have changed the Coil, HT Leads Distributor cap and rotor as it was sparking but not the strongest, I changed the Blue temp sensor, checked all earths, tried bump starting, tried another Air flow meter, Tried another working ECU, I've checked all wiring for breaks, I checked for air leaks in the vacuum system, checked the two switches on the throttle body, checked the relays, checked my sanity....

    I now don't know what else to check or what it could be! I had been driving the car for a year and she never missed a beat, she had loads of power and pulled like a train, I took her for an MOT and now crippled :-(

    I'm sure I've forgotten to list everything I checked but and I keep thinking it must be something simple unless the garage has massively broken something but don't want to tell me, But what!

    Please someone help!
     
  2. fasteddie

    fasteddie Banned

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    Sounds like they hadn't a clue mate and have killed something .. maybe a few things ..starting with your airflow meter (you would feel if the cable was disconnected) ...after a short read (will read again and give more thought to it)
    and I sure the garage had more that one mechanic
    even a muppet and a half should be able to cover the basics ...I think they have damaged your ecu mate [xx(]
     
    Last edited: Mar 2, 2015
  3. fasteddie

    fasteddie Banned

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    good detail in your post,car year model etc :thumbup:
     
  4. timms

    timms New Member

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    Thanks Mate! I suspected ECU too but Ive tried a trusted one and no change :(
     
  5. fasteddie

    fasteddie Banned

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    reading again [:-B]
     
  6. fasteddie

    fasteddie Banned

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    video looking into bay with you opening throttle ...can you do this ?
    does it bog down when you open throttle ...throttle body... it's mechanical ...cable
    ..mass air flow meter ....thinking .. is the intake pipe split ..remove this and check ...still thinking
    check flap on air flow meter is not stuck ...thinking
     
    Last edited: Mar 2, 2015
  7. fasteddie

    fasteddie Banned

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    see this is something them muppets have done ...so trying to think outside the box
    check distributor wiring..... is it plugged in even ....pull back the rubber boot on it check for broken wires
    also be worth doing this on throttle switches and airmass meter aswell .....broken wire under on of them boots sounds like a runner to me :thumbup:
     
  8. fasteddie

    fasteddie Banned

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    this sort of thing ...only takes one wire
    also check pins on connector block to ecu can push through :thumbup:

    [​IMG]

    [​IMG]

    [​IMG]


    [​IMG]
     
    Last edited: Mar 2, 2015
  9. fasteddie

    fasteddie Banned

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    cyber fixing ...not good when its not in front of you [:s]
     
  10. timms

    timms New Member

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    When It does run, when it suddenly coughs into life, it does bog down with the throttle opened. The intake pipe does have a small split but this was here pre MOT.
    Ive had a good check under the boots and everything is all good, no breaks in the wires anywhere :(
    Ive had a good look over the Air flow meter and the flap is free moving.
    Can try and video tomorrow buddy
     
  11. fasteddie

    fasteddie Banned

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    sounds like its not getting fuel ...did they have the fuel pipes off the rail ? thinking ...
     
  12. timms

    timms New Member

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    Ive checked the fuel pump, primes and works just fine.
    I have pulled the pipe off the fuel rail and with it poked in a coke bottle... it filled it within seconds.
     
  13. fasteddie

    fasteddie Banned

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    ," chuck some emissions stuff in the fuel "..... what did you put in ...wonder is it playing a part ... are both fuel pumps running ?
    dead lift pump in tank ?
    maybe worth changing fuel filter .few pound :thumbup:

    see these are easy to rule out infront of me ...still thinking :thumbup:
     
  14. fasteddie

    fasteddie Banned

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    muppets have done a number on it :cry:
     
  15. EZ_Pete

    EZ_Pete Forum Junkie

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    Are you sure there isn't a bigger, new split in the intake boot somewhere unseen? Have you taken it completely off the car to examine from all angles?
    Air leaking straight into the throttle without being metered by the AFM would seem consistent with what you're seeing.
     
  16. fasteddie

    fasteddie Banned

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    Just a thought is the exhaust ok ..clear not blocked it some way ....

    [​IMG]
     
  17. timms

    timms New Member

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    "muppets have done a number on it" thats what i have come to the conclusion of too! :( they gave me - FORTE Advanced formula gas treatment since this its been ran dry and had 20l of top quality petrol in her

    both pumps work and ive changed the fuel filter too

    exhaust seems clear certainly no bananas up there lol
     
    Last edited: Mar 2, 2015
  18. fasteddie

    fasteddie Banned

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    have you any good looking single sisters [:?:]
     
  19. timms

    timms New Member

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    Little off topic, sisters but not single
     
  20. timms

    timms New Member

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    Ive just re checked the intake boot, no additional splits. just the one small hole caused by the speedo cable rubbing
     

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