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  1. #1
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    A4 2.5 TDI AWE Engine - Missing/Broken Vacuum Pipes... Advice?

    Hi all,
    I've recently purchased a 2.5 TDI Quattro A4.
    I've noticed it seems abit "Dull" on power so i purchased a generic remap and mapped it to 208 BHP and it feels better but nowhere near what i imagine it should do, I have a 264 BHP Rover and a 188 BHP MG both of which i imagine should feel "less torqe" than the TDI Audi.

    I've also blanked the EGR Valve (Removed & Plugged the Vac Pipe). Again this made a huge difference but nothing thats saying "Wow, keep this Audi and sell the 1.9" lol.

    Anyway.
    I noticed a few things worth mentioning.

    The airbox has been replaced with this pisspoor "saxo" air filter (+500 BHP Obviously!), Behind the filter i noticed this:


    It looks like some kind of VAC Solenoid, and the left hand pipe coming off it, leads to here:


    Its open to the elements and just resting ontop of the MAF and is doing nothing at all, not even blanked, where should this go?
    I started following pipes around at this point to see if its the only one, and then i have these:



    This one leads down behind the turbo, from the above solenoid, but via a "T-Peice". and is obviously worn away.
    I'm thinking that this could be the cause, for some odd reason i noticed the pipe going to the turbo actuator is also quite badly worn and pitted, and not being held on solid.

    Would any of these pipes cause an issue? What is the one thats hanging out, not connected to anything?

    Also, Does anybody know what sizes these pipes are? id like to replace them with silicone.

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  3. #2
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    The short hose should have been fitted to the airbox, i have bought a v6 tdi quattro with a cone filter like yours and that had the nipple moulded into the rubber base adapter which fixed to the MAF- i have binned-it !
    I would get a genuine airbox in there and fit a factory paper filter, they are good enough for over 300Bhp and keep the MAF clean and oil free. Disconect the vacuum supply to the turbo and see if the VNT arm goes down and then goes up against the stop screw when you reconnect the hose !
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  4. #3
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    Your being a huge help here, but my knowledge of turbo's ends at VNT, i've never played with them at all, ever. ive always been on the older tech.

    Thanks, i guess its fine hanging out where it is for now then, im just trying to get ahold of an airbox, ive found a few petrol ones etc but from what i can see they dont have the nipple for the pipe to fit?

    Don't suppose you have any pics i could use for reference for the VNT Arm etc? and i assume whilst running/idle?

  5. #4
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    If you disconect the vacuum pipe on the turbo you should see the rod going down as it's pushed by the spring built inside the actuator, reconecting the pipe should bring it slowly up against the stop screw. If you rev the engine hard the arm should go down then up again as you release the actuator. However tdi's don't make much boost on idle or by revving them but should be obvious if the rod sticks. Any overboost/underboost codes in the ECU ?
    I have sent you a map as well, try it and see how it feels ! I would try to modify your map and send it back to you...might be by the end of the week though- very busy with work ! Cheers !
    Chris.
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

  6. #5
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    That would be brilliant if you can Would you be better off with the original 2.5 Map instead of the existing (blacksmoke mapped one)?

    And will do when i get a chance tomorrow, i think ive got some bits of vac host on my coupe so i will see if i can replace some of the broken ones.

  7. #6
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    Yeah, if you have the original ECU dump then it's better. The ECU does not have checksums so it should not have any issues...however, with MPSS you can still recover- in boot mode- a bricked ECU !
    FOR SALE:
    -Golf mk 5/audi a3 1.6 FSI fuel pump, brand new genuine part boxed + seals
    -audi a3 (1998 to 2003) genuine clutch slave cylinder to fit 1.6 engines BRAND NEW
    -Rear bush press tool to fit new rear axle bushes on Golf Mk3/4, Audi a3/S3, Seat Leon/Toledo, Skoda Octavia mk 1/2 used once

 

 

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