strange TT acceleration problem?

[porsche356]

Hi,

I allways experience a strange thing with my wifes cayenne TT (2003). When I drive the car I allways start slowly, as soon as the engine is warm and the road is clear I push the throttle completely down. What happens then is that the car shifts down 2 gears (depending on the speed) and then starts accelerating.

This acceleration goes in a strange way. It feels like it starts to accelerate and then adds on more power every second. Feels like the power is added in 4 or 5 steps. As soon as I have done this a couple of times it feels like the engine and gearbox are awake. This means that the next time I push the throttle down it gives me full power instantly.

After driving normal/slowly for a while, the procedure starts all over again. Is this a programming issue? If so, can it be changed. If not, what could the cause be then (coils?) ? There are no lights burning, engine sound good.

Any comments/ideas?

Thanks, frank

[mudman2]

Perhaps the "learning adaptive" transmission

Hi,

I allways experience a strange thing with my wifes cayenne TT (2003). When I drive the car I allways start slowly, as soon as the engine is warm and the road is clear I push the throttle completely down. What happens then is that the car shifts down 2 gears (depending on the speed) and then starts accelerating.

This acceleration goes in a strange way. It feels like it starts to accelerate and then adds on more power every second. Feels like the power is added in 4 or 5 steps. As soon as I have done this a couple of times it feels like the engine and gearbox are awake. This means that the next time I push the throttle down it gives me full power instantly.

After driving normal/slowly for a while, the procedure starts all over again. Is this a programming issue? If so, can it be changed. If not, what could the cause be then (coils?) ? There are no lights burning, engine sound good.

Any comments/ideas?

Thanks, frank

[fastboydave]

Sounds like the Turbo's are taking a while to spool up. If you've been ragging it already, they will be already spining partially and the 'lag' is greatly reduced. Also, the engine ECU (that controls all these things) will give you optimum fuel economy when driving slow (valve timing, ignition advance, turbo bypass etc) and when you open the taps it says "hold on, does he mean this? Ah, yes he does" and gives you the beans!

The only true way to find out is drive another (ask at Porsche) or take it in to see if any issue (fault codes). My 996TT is similar when pottering around, however if always 'on it' there's no such issue......

[CT44]

Try it with the PSM off...

JR

[porsche356]

Does turning the PSM off make such a difference?

I went by the dealer today for something else. I asked them whether this was normal. They said that it was programmed to give the power gradually in order to prefent to much power all at once going to the drive train.

I will try it with PSM off!

Thanks, frank

[fastboydave]

It will deliver the power fairly gradually yes, you wont get full boost straight away it 'ramps up'. Its more for ease of driving as anything else as well as not straining the drive train. However, the point you raised was that it doesnt happen when you have been driving it hard already? And my previous thoughts seem to withstand that.

[CT44]

Does turning the PSM off make such a difference?

Yes - a much more aggressive shifting program

JR