G3 AFN is slow, does not boost as should

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by ValgeKotkas, Jun 28, 2012.

  1. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
    Messages:
    12
    Car:
    Golf 3 91'
    Hi guys!
    First of all I'd like to thank this community for the 1000qa FAQ, have had lots of help from it since buying the not-taken-care of Golf. It's a 91' GTD body and there has been an engine swap done from a 97' Seat AFN manual.
    THe motor has been through 100k km according to pretty believable papers. The engine fires up with not so good fuel at -10*C with only one glow plug no problems, so I think it's pretty tight inside?

    Anyways, couple of days ago I recorded my 0-100km/h time for funs and I got 13.2 in my fastest round. Factory gives 10.8. I'm probably a bad shifter, but I can't say I shift THAT bad :D

    Then I went around and logged my 3rd gear run.
    [​IMG]
    [​IMG]

    First what came to my mind from those number is the IQ when in WOT - 41. My idle IQ was set to ~4.
    Today I tried setting it to 3. WOT IQ staid the same.

    Otherwise the engine/turbo is untouched I guess ( dismantled the VNT actuator, it had the nut stickied with the yellow stuff, so should be per stock regulations).
    Timing is slightly advance.
    EGR deleted with plates + maximum from vag-com.

    Any suggestions guys?
    I have a ball-type, without bleeder MBC laying around somewhere I wanted to use once...should I?

    Cheers!
    Jüri
     
  2. chittychittybangbang

    chittychittybangbang Administrator

    Joined:
    May 23, 2007
    Messages:
    23,901
    Car:
    2006 Jetta TDI
    Location:
    CT
    What is the maximum EGR from vag com?

    I never tried logging WOT but what is it when driving around normally? If you hold the mouse over the measuring block it should give a range of values according to what model you have.
     
  3. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
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    Car:
    Golf 3 91'
    With Maximum EGR I ment that the EGR is maximally turned down via Vag-com, not that that would matter during WOT ofc :)

    Will have to try and look at that IQ while driving! Maybe during the weekend or at the beginning of next week though :( Have to do some body work fast.
     
  4. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
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    Car:
    Golf 3 91'
    Years later and my car is still not as fast as it should be.
    1year - Got it chipped. Boost went to ~1.6bar. Clutch starter slipping shortly after. Then suddenly clutch slowly forgot to slip :) I was loosing boost permanently.
    2 year - Maximum boost I could hit was 0.7 bar. I guess the turbo started dying hard.
    3 year - changed the turbo. Got a whole 1 bar max! Yay... I guess. Put my old turbo on another tdi and it boosted 1.6 bar (ABT chipped ECU), though in a small rpm range but still.
    Changed the ECU's so now I'm running ABT and I'm still getting 1 bar with a 1.1 or occasionally now a 1.4 bar spike as I just adjusted vnt rod to N75 DC% 79 (got a flatspot, so I guess I need to lenghten it again a bit) per http://uk-mkivs.net/topic/34834-vnt...o-how-to-adjust-actuator-cure-boost-problems/

    Tried multiple N75 valves (actually the N8 or however the EGR ones are :) )
    Running FMIC. No boost leaks.

    What am I missing ?? What else can control the boost and prevent me from getting my clutch slipping again :) Why does IT correct my boost to 1bar??

    Cheers guys for any help
     
    Last edited: May 5, 2015
  5. xeno555

    xeno555 Well-Known Member

    Joined:
    Dec 12, 2011
    Messages:
    1,684
    Car:
    2012 TDI Tech Package 6mt
    Location:
    Mile High
    Mods:
    Malone Stage II. Rawtek 3" from Turbo to Tail. Slammed on Koni. TSW Nurmburg Rims. Whiteline Sway & Ends. Panzer Plate.
    Is it(n75) supplied the correct pressure?

    Can/does the actuator have full movement?
     
  6. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
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    Car:
    Golf 3 91'
    The actuator seems to have full movement. Moves freely, with fingers, the vanes too.
    Supplied correct pressure? You mean vacuum? Is supplied about 0.8 bar IIRC and gives 0.6 to turbo.
     
  7. xeno555

    xeno555 Well-Known Member

    Joined:
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    Car:
    2012 TDI Tech Package 6mt
    Location:
    Mile High
    Mods:
    Malone Stage II. Rawtek 3" from Turbo to Tail. Slammed on Koni. TSW Nurmburg Rims. Whiteline Sway & Ends. Panzer Plate.
  8. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
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    Car:
    Golf 3 91'
    96-97 AFN 81kw 1.9tdi yes.
    I've checked a lot but seems that not all :D

    Thinking about wiring - are there any diagrams online that could help me out? Maybe there's some where too much resistance in N75 circuit... What else can it be?<

    E: checked the wiring to N75 again, gets nice 12V+ and ground operates as normal, changes depending on DC%.
    Why does the ECU want 1 bar??
     
    Last edited: May 6, 2015
  9. xeno555

    xeno555 Well-Known Member

    Joined:
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    Messages:
    1,684
    Car:
    2012 TDI Tech Package 6mt
    Location:
    Mile High
    Mods:
    Malone Stage II. Rawtek 3" from Turbo to Tail. Slammed on Koni. TSW Nurmburg Rims. Whiteline Sway & Ends. Panzer Plate.
    Or


    You can remove your hood and mount a camera/cell phone to show the actuator if full use (or not). THis will tell you if it is the control for the turbo, or the turbo.

    Or

    Same but on a dyno...

    That will get you 1/2 to figure it out...
     
  10. ValgeKotkas

    ValgeKotkas New Member

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    Car:
    Golf 3 91'
    Quite impossible as it's hard enough to see the vnt moving with the eyes...
     
  11. xeno555

    xeno555 Well-Known Member

    Joined:
    Dec 12, 2011
    Messages:
    1,684
    Car:
    2012 TDI Tech Package 6mt
    Location:
    Mile High
    Mods:
    Malone Stage II. Rawtek 3" from Turbo to Tail. Slammed on Koni. TSW Nurmburg Rims. Whiteline Sway & Ends. Panzer Plate.
    Well, I'am out of ideas, good luck...
     
  12. ValgeKotkas

    ValgeKotkas New Member

    Joined:
    Jun 28, 2012
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    Car:
    Golf 3 91'
    A year later, everythings the same.
    Changed pumps electrical head - nope.
     
  13. crsmp5

    crsmp5 Well-Known Member

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    Car:
    85 kubvan
    you hook up a vacuum gauge to the vnt, monitor both vac and boost and you can see the system work that way... too bad adding boost is harder then vacuum..

    use the mighty vac to test the vnt settings first.. if they correct.. a vacuum and boost gauge will show a "sticky" vnt section in the turbo..
     
  14. ValgeKotkas

    ValgeKotkas New Member

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    Car:
    Golf 3 91'
    Interesting idea! I have to source 2 gauges then. Will try, thanks!

    One more thing I noticed after driving my buddies AFN atm Passat - his engine revs a lot better than mine. Mine is a bit like... old... doesn't want to rev as sharply at all. Can the pump mechanical unit be faulty itself? Maybe the whole problem is fuel-related? Though it smokes when floored....
     
  15. crsmp5

    crsmp5 Well-Known Member

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    just make sure to have a 2nd person to drive or watch them.. its not easy to drive and watch.. what you will see is a occasonal "lag" between the 2 if the vnt in turbo sticks.. like one pull no lag.. next pull lag... only took me a year of ****ing round till i tried this and learned more in 15 min then all the time wasted to that point
     

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