Passat B5 1.9 Tdi AFN flat spot on acceleration

[xlinuxasx]

Hello!
I have Passat B5 1.9TDI 81kw AFN engine. The problem is, when I hit full throttle, Im losing power temporarily, for about 1 sec. on ~3900RPM, after that car accelerating on full power again till limiter.

I made 3 runs with same symptoms, and made logs with VCDS on 2nd gear and full throttle:

This is group 03 (MAF)



This is group 08 (fuel injection)



This is group 11 (boost pressure)



From the logs I see that on ~4000rpm MAF suddenly goes from ~1000mg/st to 550mg/st and then goes back again to its normals. Also at the same time, fuel injection drops, same as pressure in manifold.

Turbo VNT is moving almost freely, actuator is moving ok, vacuum hoses is good, and seems that there is no leaks in air hoses or intercooler.

Any ideas?

Passat Logs.rar

[Nuz18t]

Fit a vacum gauge in actuator line and see what its doing while driving. Recently fitted turbo? Original spec turbo? Check for blockage in inlect manifold and inlect system. Remaped? Since when car has a flat spot?

[Nuz18t]

No bother, your welcome!
Cheers