AHU problem + Performance advise.

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by Jewlls, Apr 29, 2012.

  1. Jewlls

    Jewlls New Member

    Joined:
    Apr 29, 2012
    Messages:
    4
    Car:
    VW Passat b5 2000 (ahu)
    Hi,
    New to forums so don't rush to judge,
    I got a VW passat AHU engine, Recently changed head, as the old one was dameged and exhaust gas was going in to coolant, the replacement head was of a AFN engine(with injectors,and nozles(p520)) since the i have this weired problem, after the I start a car i puts ALOT of white/blueish smoke out, I asume it's burning oil, but it only takes about 5-10 mins of driving and its all gone, it only does that after being parked for a few hours, not if i stop it and then star it again.

    Now performance advise, As i mentioned it's AHU engine, so I was wondering, is it worth of upgrading Boost/vac system + ecu, or just sell it and buy AFN one? which works cheaper and easier?

    P.s: car is hard to start in the morning, I'll Have glowplugs changed tomorrow, and report back if it's improoved.

    Thanks for any advise

    Sorry for my spelling, english is my second language ;)
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  2. Keithuk

    Keithuk Super Moderator

    Joined:
    Aug 29, 2010
    Messages:
    5,328
    Car:
    2010 Golf GTD (170) CBBB
    Location:
    Stoke on Trent, England
    Welcome to the forum. welcometomyturbodies

    Blue smoke is usually engine oil burning white smoke is combustion temperature isn't high enough.

    Does the glow plug light show when you turn the ignition on?

    You could disconnect the coolant temperature sensor then see if it starts any easier that full force the glow plugs to be powered for 20 seconds. If it starts quicker then you need to investigate if the glow plugs are being powered from the glow plug relay and check the resistance of each glow plug they should be around 0.5-1.0 ohms each so you would need to invest in a multimeter if you don't have one.
  3. Jewlls

    Jewlls New Member

    Joined:
    Apr 29, 2012
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    4
    Car:
    VW Passat b5 2000 (ahu)
    Thanks,

    Yes it does, for about 3-5 secs,

    I'll do that and report back.
  4. Jewlls

    Jewlls New Member

    Joined:
    Apr 29, 2012
    Messages:
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    Car:
    VW Passat b5 2000 (ahu)
    No luck, done both, (disconnected the temp sensors, replaced glow plugs) still same hard to start in the morning AND REALLY SMOKY. Any other ideas?
  5. Jewlls

    Jewlls New Member

    Joined:
    Apr 29, 2012
    Messages:
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    Car:
    VW Passat b5 2000 (ahu)
    Can it by any chance be an EGR valve?
  6. thomasyelland

    thomasyelland New Member

    Joined:
    Nov 5, 2011
    Messages:
    19
    Car:
    vw gold tdi 2002
    Blue smoke after sitting normaly indicates valve stem seals leaking although im not familiar with this engine and if its common. This wouldnt explain the hard starting though.

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