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injector reading bad?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by bigal23, Mar 28, 2013.

  1. bigal23
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    bigal23 Member

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    [Mar 28, 2013]
    IMAG0668.jpg


    my car (140 tdi a3 bkd 99k miles 06 ) is very very poor mpg around town its 26-28 average also starts ok but sounds very rough only one the first start soon as its done a minute or so its fine even if you restart its ok.

    I have changed all filters cleaner inlet manifold removed egr checked all pipe work and everything I could think of I then used a mates vcds to jet injection quantity and they look very out of spec does anyone else think its well out or are the readings ok?

    should I buy new injectors?
    Last edited: Mar 29, 2013
    #1
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  3. NHN
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    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

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    [Mar 28, 2013]
    Search the forum for diesel purge, try this 1st.
    #2
  4. bigal23
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    bigal23 Member

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    [Mar 28, 2013]
    tried it twice 2 litres nigel I have tried diesel purge, forte injector cleaner and some new stuff called diesel rhino.

    only thing left I have not tried is injector loom and new injectors.

    just want to know if the injector reading I post above (not the large pic) is showing the injector or injectors faulty
    #3
  5. max69vk
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    max69vk Active Member

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    [Mar 28, 2013]
    Only cylinder 4 looks out of spec, have you checked the cam lobe for wear or done a pressure test on that cylinder?
    #4
  6. bigal23
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    bigal23 Member

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    [Mar 29, 2013]
    No cam wear looked it over when replaced glowplugs and Tbh I have never heard of or seen a bkd with cam wear think it was fixed on these mk5 tdi engines.

    sorted the pic out now sorry about mess about not used to uploading photos
    Last edited: Mar 29, 2013
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  7. tdi-man
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    tdi-man Well-Known Member

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    [Mar 29, 2013]
    i would say get timing cam belt timing checked by some one that knows how to do it and also set the injector timing as well.

    mine use to say similair readings untill i get the timing set correct
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  8. bigal23
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    bigal23 Member

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    [Mar 29, 2013]
    Had all new came belt done and other belt been checked by darkside and local bag place did the work. Injector timing? How do you check that can you use vcds for that and is it the injector duration?
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  9. CHEZ
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    CHEZ moderately amusing Supporter

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    [Mar 29, 2013]
    this is the technique for an a4, i would imagine the a3 to be similar,

    . re adjusting the rocker arms!
    jack up the o/s/f wheel and put the car in 5/6 gear. turn the o/s/f wheel in a forwards direction to turn the engine over and watch the each rocker arm "come on cam" when no.1 is at the peak of the cam lobe, adjust the 6mm allen key. wind it all the way down till you feel resistance, then back it off 270 degrees (3/4 of a turn). tighten up the 18mm nut.
    turn the wheel/engine again, you won't need to turn it much til no.3 is on cam. do this one in the same way.
    then no.4,
    and then no.2.

    done. stick the rocker cover on. (you shouldnt need to change the gasket as they are rubber reusable things, just give it a wipe down to get excess oil off it.).​

    #8
  10. tdi-man
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    tdi-man Well-Known Member

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    [Mar 29, 2013]
    i would go back to darkside and get them to do the injector timing as well



    #9
  11. max69vk
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    max69vk Active Member

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    [Mar 29, 2013]
    Cylinder 4 is the dodgy one, its leaking so needs to dump extra fuel in to combust (due to a cylinder leak), cylinder 2 is running lean to try & compensate for it & will be ok.

    At a guess one of the injector seals has twisted when it was fitted & is now leaking, or worse case you've got the same problem that I had where the injector wasn't fitted properly & has damaged the head where the injector sits. Try doing a compression test on each of the cylinders & Im willing to bet it will show a compression leak on No.4 .
    #10
  12. bigal23
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    bigal23 Member

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    [Mar 29, 2013]
    If the timing is ok would the only choice be new or refurbed injectors?
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  13. max69vk
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    max69vk Active Member

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    [Mar 29, 2013]
    Do a compression test, hopefully the injectors are fine & you'll get away with just fitting a new seal kit.
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  14. Rick @ Unicorn Motor Dev.
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    Rick @ Unicorn Motor Dev. Site Sponsor Site Sponsor

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    [Mar 30, 2013]
    They are pretty bad. Would suggest cam timing and injector clearance check.

    Rick
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  15. bigal23
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    bigal23 Member

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    [Mar 30, 2013]
    Been offered some new injectors with fully tested and flow sheets for a great price should I just get them and get a good deal while on offer
    #14
  16. tdi-man
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    tdi-man Well-Known Member

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    [Mar 30, 2013]
    how much
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  17. bigal23
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    bigal23 Member

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  18. tdi-man
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    tdi-man Well-Known Member

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    [Mar 30, 2013]
    waste of £400 if u ask me.

    plus u need new seals at about £20 an injector

    and new injector bolts

    Would suggest cam timing and injector clearance check
    #17
  19. bigal23
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    bigal23 Member

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    [Mar 30, 2013]
    Any guide on how to check these?
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  20. max69vk
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    max69vk Active Member

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    [Mar 30, 2013]
    #19
  21. bigal23
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    bigal23 Member

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    [Apr 1, 2013]
    thank you for the link its great info there

    anyone have an idea screen shot or something that can tell what the injection quantity deviation would/should look like on new injectors?
    #20
  22. max69vk
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    max69vk Active Member

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    [Apr 2, 2013]
    Bottom row on the screen shot below...

    ImageUploadedByTapatalk1364900582.764886.jpg
    #21
  23. bigal23
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    bigal23 Member

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    [Apr 4, 2013]
    these readings are when the car is up to temperature would they change much when the car is started cold?
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  24. max69vk
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    max69vk Active Member

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    [Apr 5, 2013]
    Not really, the injection volume would be increased as diesels need more fuel when cold, but the balance would still be out of whack.
    #23
  25. bigal23
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    bigal23 Member

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    [Apr 7, 2013]
    what would or could happen if an injector totally fails?
    Last edited: Apr 8, 2013
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  26. bigal23
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    bigal23 Member

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    [Apr 15, 2013]
    so now pulling off is very juddery like its not getting enough fuel and am having to reore to pull off is this injector or just the clutch?

    bloody car
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  27. NHN
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    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

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    [Apr 15, 2013]
    TBH if its clutch, then its expected at some point as the 8P manuals do suffer from clutch wear, especially with a stage 2 turbo with loads of torque.
    #26
  28. cal 7888
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    cal 7888 Member

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    [Apr 15, 2013]
    Replace the temperature sensor! I have the same sort of thing on mine atm! Don't rely on vcds its just an indicator and is hardly ever right! If the injector was leaking or fault it would go into limp mode extremely quickly! You wudnt be still driving it normally! I know this because my mechanic had a 2.0 tdi pd140 like mine, his injector went and he didn't even have time to notice the extra smoke, just went straight in to limp! I'm fitting a temperature sensor in mine tomorrow and wil let you know how I get on!
    #27
  29. bigal23
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    bigal23 Member

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    [Apr 16, 2013]
    Yes please let me know.

    Still getting shocking mpg drive normal it's 28-30 drive very slow and gently then I saw 38 other day this needs curing as its costing in fuel now to much, still don't know if I should just replace all injectors and loom

    plus getting glow plug 3 fault these where replaced last month so carnt be a bad plug
    #28
  30. bigal23
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    bigal23 Member

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    [Apr 16, 2013]
    Nigel it's not been mapped with loads of torque it's almost like standard Adam had amdjust map in the turbo to run smooth it's only running 150bhp roughly
    #29
  31. cal 7888
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    cal 7888 Member

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    [Apr 16, 2013]
    Just spoken to another friend and he said 9 times out of 10 its the air flow sensor! because it works out the air flow and how much fuel to chuck in! Apparantly they should be changed every 50000!
    #30
  32. bigal23
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    bigal23 Member

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    [Apr 16, 2013]
    so I had a play tonight with vagcom and altered my idle from 840rpm to 820 800 and 777. injection quatity changes with all of them but mainly with 777 (any lower car would jolt) at 777rpm it felt so smooth no vibrations or anything so quiet was great and injection quatity looked a lot beter all readings around 0.45-0.35-0.00-0.79 still injector 4 seems out but when put back to 840rpm the returned to a lot higher quatity they where 0.94-0.71-0.21-1.86 at one point inectors 1,2 and 4 where over 1+.

    is this normal as am confused that its so much better at low rpm but when back to stock seems so out of spec.

    could not keep the rpms at 777 as when pulling away the car juddered and needed more gas

    still unsure if I should get these injectors replaced am running out of ideas I have tried everything only thing I can think of

    tried the maf cleaned it with electrical cleaner spray to see if anything improved the car did for 5 min feel more responsive then went back to normal but it was nothing that was wow its fixed it proberly all in my head after I cleaned it
    #31
  33. danb986
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    danb986 In awe of VCDS

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    [Apr 18, 2013]
    So if you have a problem with an injector how much out will it be compared to the others?
    #32

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