Boost shutting on and off under slow acceleration??

[Craigybaby37_A3quattro]

got a small problem occur after buying my car about 4 months back.

Car boosts fine when u floor it but under slow acceleration in traffic or just gettin upto speed in 5th or 6th from 30mph up. when the revs reach around 2500 rpm where the turbo kicks in it feels like the boost is going on and off causing the car to lunge back an forth (kangaroo petrol style lol)

Could this be caused by any leaks in pipes from intercooler etc or can something else be causing this??

 

[LaSarthe&Back]

your MAF maybe fubar'd. Unplug it and see if it still does it.

The N75 valve plays a part in regulating boost pressure too.

Check your MAF first though.

 

[simch]

Sounds like MAF to me too.

 

[Craigybaby37_A3quattro]

thanks for the info will try unplugging the MAF at weekend an see what happens. Where abouts is the N75 valva located and is there any odd signs i should look for to see if this causing the problem??

 

[RGS3]

Hi. I'm interested in this one too - my car has been doing something similar for a long time (noticeable after my REVO remap) but the opposite way round. When I try to accelerate hard at around 2500-3000rpm it holds back then lurches (almost like a misfire). However, if I ease the throttle slower it seems to pull stronger.

I changed the MAF a while back, thought it had solved the problem but it hadnt. Also changed the N75 to a "J" which does seem to hold boost a bit longer, still have this annoying stutter though.

Let us know how you get on.

 

[a3 turbp]

i had the same problem with mine a while ago so took it to audi and 1200 pound later they found a wire had burnt out going to one of the coil packs causing the crank sensor to fail or something if that helps

 

[leecs3]

theres loads of stuff that effects boost, think i've replace everything on mine!! MAF, DV, N249 and even the turbo. Best advice i can give is let someone who knows 20V's take a look at it. Jeff Webb at awesome (ex dubsport) is about as knowledgeable as you'll find as builder of at least three 500+bhp 20V's.