MK2 8V Digifant acting strange

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

  1. fasteddie

    fasteddie Banned

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    was worth asking on the off chance :(

    what was the topic about again :)
     
  2. WillG

    WillG Forum Member

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    Have you checked the idle screw and the rubber seal on it?

    The AFM can be bypassed with a paperclip in the plug (trial and error which contacts - 1st and 3rd iirc), but if you've replaced it then that rules that out.
     
  3. mr.brown

    mr.brown Paid Member Paid Member

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    I can't help with a diagnosis but if you need a garage you can trust, give The Phirm a call - they are about 30 miles from you in Hartley Wintney.
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    Assuming its a pre-90 with CE1 fusebox, if messing with fuse 17 helped perhaps the ecu relay has packed in. its the #53 in slot 1, try swapping it with one of the other 53s on the fusebox and give it a go. you should feel the relay click when you put your finger on it and turn on the ignition.

    The ECU relay also feeds the fuel injectors on a CE1 digifant so if this was putting out low voltage that could explain why it can start and idle but wont go anywhere...

    also worth taking off the plastic rain tray and locating the 2 pin spade connectors near the passenger sid where the ecu loom joins the car loom. these are not waterproof so corrosion can build up here
     
  5. timms

    timms New Member

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    Ive had a good look at the idle screw all seems ok.

    Cheers for this pal, I really hope in the nicest way that I don't need them but its nice to know there are trusted garages out there!

    Thanks for the input mate, Ive just checked relay 53 and it clicks when the ignition is turned on, Ive also swapped it with the other 53 and another relay I had in the garage with the same diagram and rating :( still no change and to top it off it doesn't seem to want to start with the fuse 17 trick any longer, could be a good thing i suppose.

    I checked 2 pin connectors and all is good.
     
  6. john_wintle Forum Member

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    Does it appear that they have been inside the electronic section of the air flow meter?
    You will have idle as a small amount of air will pass by the flap and the idle control valve and the idle screw will be in control. If the engine is dying when it gets revved then it might be due to a bad signal from the meter.
     
  7. fasteddie

    fasteddie Banned

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    He has tried another meter ;)
    The guy to fix it ... is the Muppet who worked on it as only he can go back over his work ...otherwise it needs to be infront of someone who know's what they are doing.
    In any case the garage who broke has to fit the bill ;) as it drove in all be it a bit rich.

    Had hoped Rub could have been of more help than me ......looks like p45's for both of us :cry:
     
  8. john_wintle Forum Member

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    The problem now though is a lot has been touched or tweaked since it came out of the mot station so it is not exactly in the same state although exhibiting the same symptoms.
     
  9. fasteddie

    fasteddie Banned

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    you don't have a friend near you with a golf the same as yours to check ecu etc

    must read over it again [:[][:-B]
     
  10. fasteddie

    fasteddie Banned

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    sorta of thing I could sort fairly quick if it was here in front of me
     
  11. rubjonny

    rubjonny Administrator Staff Member Admin

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    ok next check you have a good 12v feed to the live pin on the fuel rail plug with the ignition on, you'll have to check between it and the battery -ve as the earth pin on them is pulsed by the ecu. if its low go back to those 2 pin plugs i mention and check for 12v at the black/yellow wire on the fusebox side of the connector.

    if it all seems good the next thing is go over all the plugs in the engine bay the same way eddie described for the hall sensor, in particular look at the plug on the MAF to make sure wires haven't snapped inside the boot and look at the pins to make sure they're all fully pushed in, straight and tight. I'd also unplug the ecu and check the pins here, as well as the tci unit while you're there.

    another thing, do you notice if the rev counter jiggles while its cranking, and does the fuel pump prime with ignition and run while cranking? are you 100% sure both pumps are working, as on my abf my main pump liked to cut out randomly and the poor thing was stuck trying to run on just the lifter pump alone. With ignition on the pump primed as normal, but once started sometimes it woudl loose power so it was a tricky one to diagnose! surprisingly it idled ok but it didnt actually let you drive anywhere :lol:

    a fuel injector test might be a plan, pull the complete rail and injectors out then get 4 containers of equal size and drop it in. crank it on the starter to make sure all 4 spray nice and strong, plus an equal amount. I'm not sure but if you do this while manually move the AFM flap this may trick the ecu into adding more fuel so you can see how well they spray under more load, but it may need a working rev counter signal as well before it will do that. worth a try!

    if not if you just put a live and earth to the rail connector this will stick the injectors fully open so you can make sure they still spray properly, and will also show the pump can supply enough pressure when injectors are fully open. May be worth waiting for someone else to chime in if this a good idea, i guess its possible they could be damaged? but plenty of people have had the same thing happen on their cars after blowing up their ecu and the injectors seem fine after :lol:

    oh and to rule out any problems with engine earths run a jump lead from battery -ve to the lifting lug on the front of the head, if it makes no difference this is all good
     
    timms and fasteddie like this.
  12. fasteddie

    fasteddie Banned

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    Love it ...get stuck in ma son :thumbup:
     
  13. timms

    timms New Member

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    Many Thanks for this :) its gona keep me entertained and out of trouble on my day off tomorrow. Will give all this a go and report back :thumbup:

    what does a jiggling rev counter mean? mine does do this [:s]
     
  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    this shows you that the tci unit is at least trying to fire the coil, as the coil trigger from tci is on the same coil terminal as your rev counter. so this suggests ecu is seeing a signal from hall sender and the tci unit is working at least. if you have nothing then you would need to go and check these things over :)
     
  15. molegti Forum Member

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    Just something else to add and it may be dumb but it's free. Is fuse 17 making good contact with the pins in the fusebox since messing with it seemed to work. One of my headlamp fuses is a bit intermittent as it's loose. (Until I shoved some foil in)

    Also I'd tape up the split in the hose in the hose if you haven't already. I appreciate it was there pre-mot but you may as well take that problem out of the mix.
     

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