still having cold idle problems with k-jet 8v mk2 - fuel pressure/wur issue?????

Discussion in 'K-Jetronic OEM injection' started by peteg40, Apr 30, 2014.

  1. PETEG40

    peteg40 New Member

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    Hi - a year ago I posted that my k-jet was having problems.

    I still am and the car is still in my yard.

    So.
    1. changed timing belt - was a tooth out
    2. checked ignition timing
    3. changed plugs, leads, dizzy cap, rotor arm
    4. swapped coil for a known good one.
    5. new fuel pumps and fuel filter
    6. checked alternator/battery - putting out 13.2+v
    7. cleaned all earths in engine bay and all connections in general
    8. checked all pipes for cracks etc, found one perished and replaced (isv to head)
    9. tested 5th injector - sprays as it should just on start up

    and now - its still refuses to start when cold... it sounds healthy and then dies - but restarts straight again straight away.

    I thought it could be injectors, but without the cold start injector connected it doesnt start - so doubt its that.

    I bought a pressure gauge and it shows that the accumlator holds pressure - for a good few hours after starting and comes straight away.

    However, when hot the fuel pressure gauge registers 6 bar or so which seems high and turning the tap on the regulator does nothing!

    I've looked at the pressure valve in which you add/remove washers and there's only a single washer - do i need a thinner one to get it down? I've tried 2 WURs and it seems to be the same. Is it that the WUR isn't working correctly? or should control/system pressure be the same when hot?


    I'm at the end of my tether to be honest with this!

    Happy to hear any suggestions on here - or I'm in Barnsley if anyone is near!

    Thanks in advance people
    Pete
     
    Last edited: Apr 30, 2014
    peteg40, Apr 30, 2014
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  2. PETEG40

    peteg40 New Member

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    measuring it between the metering head and the wur.

    I also measured the resistance on the WUR and its about 22ohms as per haynes manual.


    I'll check the return line - presumably it returns to the tank via the in tank lift pump as it has a send and return hoses.
     
    peteg40, May 1, 2014
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  3. rubjonny

    rubjonny Administrator Staff Member Admin

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    you should see 5 bar on the gauge only with the tap closed, if opening and closing the tap makes no difference this would suggest a blockage somewhere or the metering head is faulty. this thread details the washers you need for adjusting system pressure, but if still 6 bar tap to WUR open its probably not the pressure regulator:
    http://www.clubgti.com/showthread.php?81658

    disconnect the metering head return for the plastic pipe and point it into a bucket, redo the test and see if pressures drop and/or you get a good healthy stream of fuel returned to the tank. if no change work back from there, make sure metering head pipe is clear and check the bolt isnt the filtered type these should have been removed as part of one of the early services. though afaik the filtered bolt is only on the inlet pipe not the return, but check anyway in case one has been put there by someone in the past.

    failing that another metering head would be on my list of things to try
     
    rubjonny, May 2, 2014
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  4. PETEG40

    peteg40 New Member

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    Cheers. Will have a look tonight.
     
    peteg40, May 2, 2014
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  5. PETEG40

    peteg40 New Member

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    have been playing tonight... here are the results.

    Both pipes to the WUR are clear - i've taken them off and blown down them.
    I ran the return pipe under the car to a bucket and fuel is being returned
    I thought the aftermarket (not bosch) replacement fuel pump might be over pressurizing so I swapped it for the noisy old one.... same pressure.
    I thought the pressure gauge might be faulty so I ran the pressure gauge to a bucket and the tap works fine! and you can reduce pressure to 3/less bar by opening the tap to various degrees.

    I swapped the metering head for another and I get exactly the same result!!!
    With thinner washers on the pressure valve I can get the pressure to just over 5 bar... but still doesn't vary with the tap closed!

    I've got a 16v wur. I'm going to try that on and try adjusting that and see if it makes any difference at all!!!

    Will see what tomorrow brings.
     
    peteg40, May 2, 2014
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  6. PETEG40

    peteg40 New Member

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    sorted. Was the WUR. stuck a 16v one on and it runs fine, just over 3 bar tap open, 5 bar tap closed!

    thought the accumulator is goosed! doesn't hold pressure and bad at hot starting. All they all the same on mk1/mk2 golfs/corrados KR/EV/DX?

    Cheers,

    Pete
     
    peteg40, May 5, 2014
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  7. rubjonny

    rubjonny Administrator Staff Member Admin

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    same fitment for the pipes,. but some on later kjet/pl/9a are a bit smaller but will still work with a sleeve or something so its a tight fit in the pump bracket
     
    rubjonny, May 6, 2014
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  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    forgot to say, you might want to try the non-return valve in the pump first rather than the accumulator, as if it was that loosing pressure I'd expect to see a fuel leak somewhere! the nr valve is what actually holds pressure really
     
    rubjonny, May 6, 2014
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  9. PETEG40

    peteg40 New Member

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    Which/where is the nr valve? The one that screws into the pump that the banjo fits on? Its a new one that came with the aftermarket pump...suppose it could be rubbish quality

    I had same issues with two different accumulators... So I thought it must've been the uber high pressure blowing em..neither leaked.

    I can try the valve easily I suppose, I've got others.
     
    peteg40, May 6, 2014
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  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah thats the one, if its aftermarket it may not be a n/r valve just an adaptor I suppose
     
    rubjonny, May 7, 2014
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  11. PETEG40

    peteg40 New Member

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    switched the non return valve. And still the same issue.

    It was quiet and I heard a whistle near the fuel pressure gauge. It turns out there weren't enough washers on the pressure valve on the metering head. Added a couple more thin ones and it holds pressure - still nearly 3 bar after 40 mins.

    I therefore need to reduce the washers to the point where the system pressure is as near to 5 bar as possible, but it holds pressure when not running.

    I think i cracked it.

    Thanks ever so much mate!!!

    Pete
     
    peteg40, May 7, 2014
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  12. PETEG40

    peteg40 New Member

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    MOT here i come!
     
    peteg40, May 7, 2014
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  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    sweet [:D]
     
    rubjonny, May 8, 2014
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  14. PETEG40

    peteg40 New Member

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    Now passed mot after 6 years being stood!

    Was very lean though.


    Do I just get a probe up the exhaust vent adjust the Allen screw to 2% co?

    Pete
     
    peteg40, May 25, 2014
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  15. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah 1.8-2%, assuming you have checkjed it all over no air leaks or anythign and ign timing all spot on :)
     
    rubjonny, May 27, 2014
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  16. PETEG40

    peteg40 New Member

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    IG timing done and it idles spot on about 950 rpm! Just mot showed it lean and seemed kinda slow!
     
    peteg40, May 27, 2014
    #16

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