S3 Performance loss..please Help.

[squale]

Hello,

I would to expose a problem which i experience with my S3 as i am becoming desperated.

The car : 2002 225 S3, ABT remap, stainless steel catback exhaust, silicone induction hose, cotton panel air filter in standard airbox, which was running very fine until the following pb occured:

When I log the boost with VAG COM, It never reach the target boost: i.e: 2300 mbar instead of 2500mbar for example between 3000 rpm and 4000 rpm.

Moreover, I especially feel a strong loss of power of the car, especially in recovery, and what is strange it is on motorway in 6th gear for example, when I floor the gas pedal, the boost sometimes stagnate (i monitor with a gauge) and pass suddendly to full boost (1.3-1.4bar,but not to the requested 1.5 bar), this stagnation problem seems to disapear when unplugging the n249, but despite everything, the performance still remains poor.

Another phenomenon: sometimes when I release slightly the gas pedal , i feel the car pulling stronger..

I guess that all this must be dependent but I despair to find a solution now.

I replaced with new oem parts : dump valve (710N), the n249 and n75, as well as the suction pump (small Y of plastic) under the intake manifold (which was leaking oil). I also inspected all the hoses and connections I do not find any leak.

Thank you for your assistance.

[BlackS3]

Have you checked the MAF??

[squale]

I checked it yes, values between 180-195 g/s, is it normal ones ? Could the maf can create such problems ?

[BlackS3]

Shouldn't the MAF values usually be 230-250 g/s. Don't quote me as I'm sure this figure is different for different models but a fault I had with MAF was spurious readings from it.

[squale]

Shouldn't the MAF values usually be 230-250 g/s. Don't quote me as I'm sure this figure is different for different models but a fault I had with MAF was spurious readings from it.

The maf has been changed, no improvements, or slightly...