A4 B5 1.8T question on Boost

Started by killerb09, Mar 13, 18, 07:23

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Another car question for my daily driver.
Car is a AWM 1.8T 5spd Quattro 2001 175kms

I installed a stage 1.5 ecu in the car and now have a funny issue.

Car pulls hard after 3000rpm and 1/2 throttle.  Almost feels like a old 2stroke power band.  Below this it feels average if not below avg.

DV is OEM(may be original)
N75 is OEM(may be original)
running Shell 91 fuel.
Giving a random CEL without a code(generic OBD2 reader) and will update once scanned with VAGVOM

Would either the DV going bad or the N75 going bad cause these symptoms?

Car ran ok on the stock program and now it is running 15psi boost program and does pull pretty hard in 3rd gear highway pulls testing.

any help from the Audi gods is greatly appreciated. 


Did you find out what the code is?   I have the same engine/car combo.  Can do some logging with VCDS if/when you have it.    Who's tune?


Tune is by MTM out of Germany, not sure how I got my hands on it in Canada as I bought it 2nd hand out of the USA.....well travelled.

I figured out the "blank" code after sparking up VagCom, it was used in an Auto car and mine is 5spd, soft coded it to 5Spd and the TCU code(which was the blank code) was cleared and stayed away.

Still have the "surge" boost thing happening, next up will be a fresh N75 boost control valve and upgraded DV and new plugs.  I also have a code showing for a bad 02 sensor(heat circuit code bank 1)

I have a feeling the tune is set for 94octane fuel as well and the best I can get here is 91, it ran noticeably worse on the 87 I had in there for a bit.

I may end up swapping the oem tune back into the car until I get the required parts together to take advantage of the full tune.


I think you should probably get a tune that was made for your car and not some randomness from Germany.   Their fuel is far better than ours, and calibrations from over there may not work.   Also no idea on injectors etc.    Just saying trying to sort hardware out for an unknown tune can be a nightmare.   Its quite easy to test your DV, just take it out and make sure its still holding.  ( can do this with your hands ) N75 is harder to track down, but if you install a boost gauge you can see if its doing something crazy.  Logging with VCDS would be better.   Other thing that it could be if you haven't done it is a throttle body calibration.  Should be done any time the ECU is disconnected, but certainly any time an ECU changes cars.


I only currently have the VCDS Lite trial version, doesn't allow calibration to happen with its limited capabilities, but will have it completed soon by a friend.  I've tracked the Boost to peak at 19psi and taper to 15psi and then drops considerably. 

I honestly got the tune for a great price and although only know what's on MTM's site it works pretty good in the car.  This is my first boosted car so it's a learning curve on a $1000 winter beater.  lol

Once the weather gets warmer(-10 here still) I'll dig into it a bit more and start ruling out things that might cause issues.