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++++++ NO BOOST ON 2.5 V6 TDI +++++++

gmac78 Jan 19, 2013

  1. gmac78

    gmac78 New Member

    Hello all,

    I've just bought a 2002 a4 2.5 v6 tdi and having some issues. Basically i bought the car as a non runner with a suspected fuel injection pump problem. The previous owner had been given some dodgy advice as a proper bleed of the fuel system seen her fire back into life.

    Anyhow, theres no MOT on it at the moment but couldn't resist a wee spin up and down the road to see what the power delivery was like. I only managed a couple of short blasts before all boost pressure was cut. Im not sure what these cars normally feel like but it didn't feel like there was much of a kick when the turbo spooled up. Certainly my previous 2005 A4 2.0 TDI 140bhp felt a lot quicker.

    When i got the car there were several problems with a snapped VAC IN nipple on the N75 valve being one of them. I replaced this with a new genuine N75 valve and reconnected all pipework. The turbo actuator stroked freely when the car was started up but now following boost cut the actuator does not move. I connected a vac pipe directly from the vac pump on to the actuator which moved it freely with no sticking. All vac pipes that i can see around the top off the engine bay are in good condition with no splits.

    I purchased an ELM 327 bluetooth diagnostic tool which i tried using with the TORQUE PRO APP. For some reason it is showing no faults although the live data function seems to work. I tried unplugging the MAF whilst the car was running to provoke a fault but still nothing showing up. Not sure if the ELM 327 is compatible with this year of audi? Disconnecting the MAF made no difference to the sound of the engine whilst idling. I've also tried disconnecting the battery for a few hours to see if that would make any difference but still no joy!!

    Sorry for the long rant but what can be causing the actuator not to move freely when plumbed in through the new N75?

    Any ideas much appreciated guys.


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