The Plot Thickens

Discussion in '8-valve' started by I'mMarkTwoToo, Oct 5, 2018.

  1. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    Ok, so I'm trying to sort out the rough running/idling and so far I have cleaned out the ISV (buzzing nicely), cleaned out the throttle bodies, replaced the UFO and bung, checked vacuum hoses, removed the blue sensor (engine splutters and dies - cheers Tristan and rubjonny) and still nothing has made much, if any difference. But, what I have just found is that there are no hoses running to/from my airbox, other than the intake hose and the blue/red wire on my MAF connector is broken. I've also noticed that the oil temp on the MFA only ever says "160" regardless. Could all or some of this be contributing towards the dodgy running - I'm guessing the MAF is the biggest candidate?[​IMG]
     
  2. Tristan

    Tristan Paid Member Paid Member

    Joined:
    Apr 25, 2006
    Likes Received:
    1,213
    Location:
    Southern IRELAND
    Definitely fix the maf, rather than splice , I'd get some new power timer connections and repin it. Though a good splice is fine ,just not as neat .
    Also check the pins aren't corroded on the maf .

    The hoses to your airbox, other than the big one, are the small plastic vac lines in the picture. Only the top one goes to the engine, to a Tee piece near the fuel pressure reg.
    Are you sure the blanking bung on the throttle body is intact ? Behind it? And that the vac line for the mfa is OK?
    Plugs?
    Timing?
    Idle fuel mixture?
     
  3. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    I'm fortunate in that I work with aircraft avionics guys so I will call in a favour to get that wire sorted. On the airbox there is a bloody great hole on the bottom towards the front of the car and another facing the bulkhead, I opened the 'box and there is a big plastic hinged flap inside behind where the rear facing hole is.

    There is a hard bung in a small length of hose attached to the rear of the throttle body.

    New plugs were fitted at the MOT about three weeks ago because it wouldnt start, the garage had to mess with the mixture as it was reading "between 7&9", they were in the process of doing the timing at the time I was there to collect the car.
     
  4. Tristan

    Tristan Paid Member Paid Member

    Joined:
    Apr 25, 2006
    Likes Received:
    1,213
    Location:
    Southern IRELAND
    Aha. the holes , one is supposed to have a pipe heading in the direction of the exhaust mani , to take in warm air to help cold running , the other should have a trumpet type effect that goes to the headlight area, that's where air gets in .
     
  5. Tristan

    Tristan Paid Member Paid Member

    Joined:
    Apr 25, 2006
    Likes Received:
    1,213
    Location:
    Southern IRELAND
    Between 7 and 9... Ignition advance in degrees , maybe .. But nothing in the fuel mix sounds like that . 1.8 % CO maybe .
     
  6. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    Yep, nowt there, just holes. More bits missing then.
     
  7. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    Found out that Team Mulisha, who run mk2's in various states of looniness including an R32 engined 572bhp monster are based in the workshop behind my hangar. I think I'll have to be paying them a visit on Monday!
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

    Joined:
    Oct 31, 2003
    Likes Received:
    3,318
    Location:
    Bracknell
    the warm air system doesnt make any difference that I've noticed, mine has been disconnected since 2005! for the front hose people pull the snorkel out for a bit more induction noise, if you want it like oem then hunt around for the plastic shroud that fits aorund the driver headlight. you'll probably find the bottom half is still there just need to get the top part and maybe the snorkel bit too if missing

    oil temp display will be unrelated to running issues, all it will be is either the little white sensor in the oil filter is dead or the green/black wire has fallen off it and earthed out
     
  9. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    Cheers once again RJ. I've read about removing the snorkel but wasn't sure what it was as I didn't have one to look for! On top of the MAF wire being broken, I found another broken wire going to the throttle harness connector (?) on top (or could be behind, I can't remember) the throttle body. Should be two wires going in but I only have one and a half so hopefully I'm getting close to finding the problem and solution. Luckily one of the avionics guys at work said he will sort them both out for me.
     
  10. rubjonny

    rubjonny Administrator Staff Member Admin

    Joined:
    Oct 31, 2003
    Likes Received:
    3,318
    Location:
    Bracknell
    sounds like the idle/wot switch plug to me, common for them to snap.

    junior/power timer pin same as the AFM pin you need to fix though the idle switch plug wires need a wire seal on which you slip down the wire, crimp pin on, then slide seal back up to cover rear of the terminal. The plug itself is junior/power timer 2 pin as well, industry standard so easy to get a new one if you need to
     
  11. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    I'll pass all that on - went way over my head. I did notice that when I press the WOT switch the revs would just rise instead of falling.
     
  12. Tristan

    Tristan Paid Member Paid Member

    Joined:
    Apr 25, 2006
    Likes Received:
    1,213
    Location:
    Southern IRELAND
    https://goo.gl/images/QsvCqv

    And a rubber boot like what newer models use helps support the wires .
    https://goo.gl/images/NiomCt
     
  13. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    That's fantastic, cheers Tristan. One way or another I'm determined to get this bloody thing sorted and your help is fantastic. I've been a member of forums in the past and they seem to be used for slagging people off or used as an opportunity to show off and make others feel inferior or stupid. How I miss those forums..Only kidding, this is exactly the kind of help I need and really is appreciated.
     
  14. Tristan

    Tristan Paid Member Paid Member

    Joined:
    Apr 25, 2006
    Likes Received:
    1,213
    Location:
    Southern IRELAND
    Cgti is THE place for technical support .
    A lot of serious knowledge here . We don't say an awful lot , but usually when someone like Rj or Toyotec or TonyB etc speaks, it's worth paying attention.
     
    I'mMarkTwoToo likes this.
  15. valvemiester

    valvemiester Paid Member Paid Member

    Joined:
    Jan 24, 2013
    Likes Received:
    108
    Location:
    Trowbridge
    I had the wiring on the WOT break, car idle was fine but throttle was on / off like a tap when either accelerating or backing off the accelerator not smooth at all, sorted the broken wiring and all was fine (mk2 GTi 2l 8v)
     
  16. rubjonny

    rubjonny Administrator Staff Member Admin

    Joined:
    Oct 31, 2003
    Likes Received:
    3,318
    Location:
    Bracknell
    you would just carefully dig the boots out of the old terminal usually, if your mate has a set of good release tools the original plug housing can be reused too though once the wires have been tugged out it can be a real hassle to get the pins out.

    probably easier to cut a donor plug off a scrappy car and graft in, as now wires snapped you may find theres not enough length on the originals anyway. or you might want to pull the ecu loom out and strip it down completely for full repair right back to ecu, since you have at least 3 wire breaks that you know of this might be the best plan?

    with the digi its handy as the ecu loom splits off from the main harness in the scuttle and at the coil plug then comes out without havign to go back to the fusebox. then you can strip it for repair, or drop in a new loom which is in better nick. only thing if you go that route is CE1 and CE2 digi looms differ at the connecting plugs in the scuttle, ce1 has 2 spade plugs and ce2 has a 5 pin timer plug.

    Its easy enough to adapt either way since the wire colours match up, just the CE1 ecu looms have 1 less wire to the fusebox as the injector and ecu power are fed from the same black/yellow wire and on the CE2 loom they have separate red/black to fusebox for injector power. you can ignore the ce2 red/white its lambda heater power and is unused for UK spec
     
  17. I'mMarkTwoToo Forum Member

    Joined:
    Sep 27, 2018
    Likes Received:
    2
    You were dead right rubjonny. The wiring is in such poor condition and so brittle it was just breaking away. He managed to do a temporary splice on the wires tonight before it got dark and the engine was idling much better but kept dropping and rising between about 800 and 1200 rpm. I did order up a couple of those junior 2 pin plugs so he will fit them as soon as they arrive. But I think he was surprised but just how poor the wiring is, not the condition as much as the lack of care that has been taken by the last owner over the amount of electrical tape that has been used. He also noticed that the bonding lead on the side of the engine above the gearbox had been cut to about an inch in length and went nowhere.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice