PCAR996C2

Hi guys just bought a new to me 2002 996 TT, tip. Its was tuned by JZM in the UK 8 years ago using a Manthey DME programme to give around 490 HP. Everything else is stock. It now lives in NZ.

Issue: sometimes it boosts so hard I make involuntary whoops of glee. Other times it is just fast, but not ridiculously fast. There doesn't seem to be a pattern to it so it can be a bit disconcerting because you're not sure what you're going to get...

Also I have noticed in manual mode put it in 3rd or 4th and it boosts really hard to say 1.1 bar, feel the shove, then it backs off quite a bit without a corresponding back off on the throttle.

Any ideas in what is happening?

Atrox

RDS928S

Just perform multiple roll on full throttle pulls & record boost reading from dash gauge . It should spike to max boost then settle into steady boost reading.
If the boost reading is sporadic then u have a boost/vacum leak.

Good Luck

Dock

If you have any hills in your area, or even a steady incline, start in a higher gear at low RPM and go WOT going up the incline. You will get a very good idea of what sustained boost the car is capable of producing.

PCAR996C2

Thanks for the tips everyone I will give them a go.

Carlo_Carrera

Check the linkage behind the gas pedal. It is a ball and socket set up. Sometimes the ball can become dislodged from the socket when the carpet is being vacuumed and create inconsistant throttle.

Also do and e-gas reset. Use search for the procedure.

911mhawk

Data logging your engine with some technical expertise to help evaluate would be a good thing.

PCAR996C2

Yep off to shop next week for service etc.

Sveach756

This buy a durametric it will pay for itself very quickly and usually you can post logs and have help on here. If you need a basic log recommendation file PM me but most of the timers are super helpful and will do the same.
Shawn

PCAR996C2

Hi guys the problem was a faulty N75 boost control valve (frequency valve). The old one was causing the over boosting which resulted in timing being pulled and thus the power drop from time to time. The new valve has transformed the car it now pulls like crazy all the time. Even on half open throttle when the boost kicks after a second you get a mighty shove in the back So cool!

T Kono

Good deal. Can you recall the steps taken to reach the diagnosis?

PCAR996C2