Bryans12v

It may not be an Audi but its damn sure close enough.

A friend and I have been trying to put our finger on a problem for a while now. Hes got an 03 GTI (AWP) with the ATP stage 2 turbo kit, FMIC, downpipe, full exhaust, HF cat, race N75 valve, EIP GRreddy's BPV kit, pretty much the works outside of headwork, pistons, etc..

At fisrt we were running the APR 93 program which left us overboosting terribly (spiking 25lbs) and throwing the car into limp constantly. We just switched over to ATP software and now the car is holding 15lbs and surging to all hell. He has been a VW tech for years working for the dealership I work for now and knows alot about tuning cars broadly and it still stumps his brain, as well as mine.

What I was wondering is by logging a few graphs, would you guys be able to lead us in the right direction to find a problem? If so, what blocks would be appropriate to post?

The car is running a wee bit rich now and pretty much the only thing that hasnt been replaced is the MAF. As I type he's putting in a manual boost controller to see if he can work it out manually but I could still use all the help I can get.

Please, if you guys at least think you may be able to help out, please do so..

Thanks,

Bryan B.

Yippers®

I'd try going back to the APR software (this is assuming ATP software still sucks) after going to a new OEM N75 valve for that application.

[ej257]

As I understand it they went back to the stock N75 and still had problems with APR and ATP software. Last update I got they were installing an MBC, but that will only mask the problem IMO. ATP was no help when they called and asked to help problem solve.

Could it be the MAF? What blocks (other than boost and timing) to log?

Audi2ptzero

the ecu is shutting the throttle body when it goes over 1.45 bar (21psi) of boost. There is a block on the vag (054 for the A4), that will show this by giving throttle pedal and throttle body values at WOT.

Yippers®

symptoms. I know the APR cars (long and transverse DBW) don't have issues with the throttle plate closing due to boost exceeding 21psi as Mike suggests. IIRC several transverse owners found the vac plumbing on the N75 control circuits was not correct.
Perhaps you could log into Ed's place and post this in the A4/S4/TT forum. You'll get a better signal to noise ratio and, I think, faster response times. I'm sure a few of the transverse guys would see it and be happy to respond.
In the mean time, I dropped a link and request in the transverse forum to this thread as well.

WJM

since they are dbw the MAF is more than likely max'd out with the airflow, and utilizing the MAP... so we are probably looking at either a leak, MAP sensor, or programming control issue.

I'd vag it to see throttle body %, airflow, requested and actual boost.

after that I would do an end to end pressure test to make sure there are no big leaks, what is BPV is being used?

Wolk's Wagon

Overboost valve kit from boostvalve.com, should fix you right up.

As well as ditching the N75 Race.

[ej257]

I don't know which it's set to.

Bryans12v

We tested for leaks twice and nothing came up.

By any chance, do you know what blocks #'s to log?

Bryans12v

I really havent been around the boards much lately and currently dont have the link to find Ed's place.

Thanks for dropping the link for me.