97 Passat TDI - Acceleration Issues

[EtherNut]

When I really get on the gas for hard acceleration, my Passat seems to hesitate slightly at several points on the Tach. I'm curious as to why this happens. It's like my boost fluctuates on then off repeatedly. Any direction would be appreciated!

Thanks!

EtherNut

 

[oilhammer]

Check your intake system, especially post-turbo (the boosted part, including the path to and from the intercooler) for air leaks. I had a similar problem for a long time with my A3 Jetta (very similar in design), and suddenly it got really bad and a CEL came on with a boost deviation code set. Turned out I had a small tear in my charged air intake hose going into the manifold. Replaced that, and all the problems were gone. It must have had a tiny hole for a while, and finally let loose. Car still ran good at low RPM and low boost.

 

[EtherNut]

What is the best way to go about searching for leaks? How did you find that you had a torn charged air intake hose? Could you hear the leak or did you just run across it? I apologize for asking so many questions. I do want to get to the bottom of it though. I have a Vag-Com if that would be useful. My car has never thrown a CEL code to date.

Thanks!

 

[oilhammer]

I just started visually looking over all the tubes and ductwork, as well as the intercooler as best I could see. Once I saw the split in the hose it was pretty obvious. Also check all the hose connections going to and from the N75 valve, as well as the one that goes to the MAP sensor in the ECU, from the intake tube.

 

[MacGyver]

My 97 Jetta does the exact same thing, markedly worse when it's cold outside (did it last winter too). Barely perceptible or non existant in the summer. I'm thinking cleaning N75 might help? If it's gooped up, the 'goop' is thicker when it's cold, restricting smooth operation...

 

[Dean_S]

Our 97 Passat was surging the previous last two winters. Not this winter (so far). I cleaned out the intake and chip'd the ECU as well. I am thinking that the fouled intake was part of the surging problem. Using Premier for the first winter too.

 

[Captaingomes]

My 97 Jetta does the same thing. It seemed to be worse on the highway. I also notice a general lack of urge from the engine at higher speeds. Low speeds are fine though.

I've had Oakville VW hook up the car to their computers, and nothing was found. They removed the snow screen, but the problem remained. I would like to solve this problem as well.