HOW TO: Set System & WUR fuel pressure

Discussion in 'K-Jetronic OEM injection' started by gti_kev, Jan 5, 2006.

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  1. THEBOYMIKE

    theboymike Forum Junkie

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    Nice video find :thumbup:
     
    theboymike, Nov 19, 2009
    #41
  2. DOGZILA

    dogzila Forum Member

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    Example my wur pressure is 3.4 bar, and I add shim, so control pressure rise or fall?
     
    dogzila, Nov 1, 2010
    #42
  3. rubjonny

    rubjonny Administrator Staff Member Admin

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    wur pressure is changed using the allen key, its the system pressure you adjust with shims. this needs to be set at 5 bar.

    see point 5:
     
    rubjonny, Nov 2, 2010
    #43
  4. CHRISMC

    chrismc Forum Junkie

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    Would I be right in thinking a 2L conversion would have the effect of leaning the idle mixture due to extra cylinder filling?

    Is this the same throughout the range?

    System pressure is spot on with control pressure previously set to 48psi (whilst the KR motor was fitted)

    Weighing up whether a setup is going to liberate more go? Feels great as is- but worth the spend if further wur and ignition tweaks are required. Currently running 9degs of advance..
     
    chrismc, Nov 2, 2010
    #44
  5. rubjonny

    rubjonny Administrator Staff Member Admin

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    changing the engine will require tweaks to the co mixture one way or another. apart from that a std kr setup should be able to handle a 2.0 no problem at all, as long as everything is working right
     
    rubjonny, Nov 2, 2010
    #45
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    engine swap alone shouldn't effect the pressures if thats what you mean
     
    rubjonny, Nov 2, 2010
    #46
  7. CHRISMC

    chrismc Forum Junkie

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    Thanks John

    I tweaked the mixture up a knats as the tickover was a tad lumpy. Sorted that out a treat. Will check and adjust co at next MOT.

    I guessed that the pressures would all remain static- but wondered if control pressure requires further adjustment from 48psi?

    Pulls cleanly as it is but no idea on whether afr needs further tweaking due to the bigger capacity. From what you are saying I'm guessing the fact the control pressure has already been tweaked and mild spec should mean it's ok!
     
    chrismc, Nov 2, 2010
    #47
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah the system is closed so it shouldnt make any difference changing the engine. you may need to tweak the wur, thuis comes down to your afrs. ideally the wur should be set properly on a rolling road, 48psi is just a guesswork figure, will add a little extra fuel but it wont be correct for everyone
     
    rubjonny, Nov 2, 2010
    #48
  9. CHRISMC

    chrismc Forum Junkie

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    Cool.

    I think il book it in for a setup to give a baseline figure before deciding on my next mods...

    Will be a while seeing as the first mini-mc is due on the 7th! VWs will be taking a back seat for a while!:lol:
     
    chrismc, Nov 2, 2010
    #49
  10. DOGZILA

    dogzila Forum Member

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    normal pressure is 4.7-5.4, I want to rise pressure to 5.5 bar, did this increase or decrease control pressure (WUR)?
     
    dogzila, Nov 3, 2010
    #50
  11. rubjonny

    rubjonny Administrator Staff Member Admin

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    id assume it would raise the control pressure as well, since from what i understand the wur reduces pressure by x amount from system pressure if that makes sence? you would want to have a pressure gauge plugged in to tweak the system pressure anyway so you can check for yourself if control pressure is effected :)
     
    rubjonny, Nov 6, 2010
    #51
  12. DOGZILA

    dogzila Forum Member

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    I read in vwvortex, when you increase system pressure, then also you have to increase control pressure (WUR) for better divebility (lean mixture), so control pressure decrease.. :)http://forums.vwvortex.com/showthread.php?695555-Increasing-total-fuel-system-pressure-CIS&highlight=System+Pressure+cis f
     
    dogzila, Nov 6, 2010
    #52
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    oh i see what you mean now! yeah you would want to check the afrs afterwards and adjust the wur to suit. its not something you can just mess about with an arbituary fgure as all cars are different. just happens that 48psi does work well when everything else is std. you may have to adjust this depeindign on state of tune etc
     
    rubjonny, Nov 6, 2010
    #53
  14. CHRISMC

    chrismc Forum Junkie

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    Idle co reset today. Was a tad rich with idle co at 10% after my quick twist on the mixture screw post engine swap[:$]

    Seems happy enough on 2.5% now.

    Will book in for a setup at Stealth and see where it's at:)
     
    chrismc, Nov 6, 2010
    #54
  15. DRAGOV

    dragov New Member

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    I've recently managed to buy a tester for K-Jet to test the WUR and fuel system pressure on my 16V KR, and i noticed that the control pressure goes directly to 3.4 bar (when cold), instead of starting from 1.5bar and going slowly to 3.4.
    Could it be the bimetallic spring boken? I want to mention that the first time when i tested the pressure, the control pressure was at 5 bar, and i used the drilling method to adjust it to 3.4
     
    dragov, May 17, 2018
    #55
  16. rubjonny

    rubjonny Administrator Staff Member Admin

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    something definitly isnt right, cant hurt to take it off and split it down to see whats what. there is a wee mesh filter on one of the ports this might be gunged up
     
    rubjonny, May 18, 2018
    #56
    MUSHY 16V likes this.
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