Sti PPP holding back
 

It seems to be holding back slightly at high revs i.e. over 5k.

Also seems more noticeable in lower gears 1st, 2nd, 3rd.

Whats it most likely to be? And whats the worst :brickwall

Dump valve letting by?

Its an 04 car and is still under warranty so it'll be over to Wilsons asap :(


Thanks, Rob

Bad tank of fuel could of reduced the timing?
Get some fresh tesco 99 in the car and go for a good drive.

Really..... I hadn't thought of that.

I use V power but I have heard of bad batches before. My only problem is I'm supposed to be getting it remapped next saturday :cry:

Should I take it back to the dealer and get them to check anything :confused:

Try the fuel first, the mapper should see any problems during the mapping. But this could halt your mapping session.

Where are you getting it mapped? extreme or mocom?

Bob Rawle :thumb:

:thumb:

Have you by any chance changed the air filter to a cone ? did that on mine and held back at 4k and over then put em light on . Getting to much air was the fault ! was cooling maf wire to much , prodrive said it would need a remap to overcome this or a longer pipe before the cone filter .

No mate, nothing changed at all........



....... Tell a lie, I've probably done ten or so tanks of V power since T99. Thats the only change I've made in months.

Rob,

Don't worry about it - bob will sort it out. I'm with him on Saturday :D

Check the tyre pressures.

Have you had fuel surge lately? By this I mean a lack of go out of a roundabout or similar on lowish fuel. If you have, it may be that the ECU picked up some det and has some negative values in the learnt ignition tables at higher rpm. Ordinarily this would get removed as the ECU relearns but at high rpm that's not too easy as it doesn't stay at the load sites for long enough. A reset would get rid of it but if Bob's remapping it the learnt ignition tables will be cleared.

Mike

Thanks for replies :thumb:

Tyre pressures :lol:

And no, not had a problem with fuel surge. Felt it in a cossie before - nose on the windscreen was the worst example - and had small amounts too, but it doesn't feel like that in this instance.

Just noticed another point that may be of note - this problem was still there coming home from work tonight but I must add that it stops holding back and 'goes for it' like it should, after 7k rpm.

Probably been the same since I noticed it but not given it that much till tonight.

Shed any light on anything for you guys :confused:

Its also got £43 worth of V power (brimmed) from a different garage to what I normally use now. Done 25 miles since filling and no change yet.

Any other suggestions? I'm gonna fit a boost gauge temporarily tomorrow to see what I'm getting (pipe through the window a la cossies of old :D ) so I'll give feedback on what I get tomorrow afternoon/night.

Bit worried still :(

Just thought I'd add, fitted the boost gauge and gave it a run. I know the scale of choice is bar on here but I still work in psi :p

Peaks at 19psi in 1st, 20psi in 2nd, 3rd & 4th gear.
Settles at around 17/18 and over 6k it drops off to 15ish where it stays to the limiter.

Sound about right :confused:

It certainly doesn't fluctuate like the power does. Theres no correlation so I'll assume that the turbo and assoc. pipework/valves/etc are ok.


Whats next???

It's probably pulling the ignition timing as it picked up some det at higher rpm. Reset the ECU, the learnt table will be cleared and the flatspot will be gone.

Mike

Shouldn't be detting using V-Power as thats miles better than anything we have ever had but as Mike says if it pulled some ignition over something then it won't give it back easily, I can check the fine learning when I see you and mapping adjusts ignition, boost and fueling appropriately to suit the car (and your driving style). There's also a fair amount of change involving the associated settings for det control and ecu reaction that will all combine together.

One thing, it could just be a bit rich in the area you mention. The holding back could be actually the engine choking a bit on too rich a mixture, some previous unhappiness could contribute to this.

cheers

bob

Thanks for the replies.

I'll see you saturday Bob :thumb:

Faulty Neutral Position switch?

I had this problem on mine. Was effecting the VVT. It was never static, ie. happened always at a RPM or gear. But it was holding the car back and losing plenty of torque.

It showed up during a mapping session. 2nd gear OK, 3rd on & off, 4th off, 5th off 6th on and off.

Had it changed under warranty and made all the difference.

Kept initially thinking the wife had switched to low-boost, but then the next minute the car would go again.

Sounds unlikely but what do I know :wonder:

We'll see on saturday :thumb:

Had the nuetral position switch problem to. When i accelerated hard the swiched droped out and showed i was in neutral. Switching the vvt off. Showed in gear as it should if i just cruising

For those interested, Bob went straight to the problem on saturday when I arrived.

It was a short (bout 1" long) piece of vac hose that went from inlet manifold to some exhaust gas recirc thingy :wonder: It was very loose on the hose and was allowing unmetered air into the system causing my problem.

Bob swapped the hose for another short piece and fitted clips to be certain.

Just FYI :thumb:

Thanks Bob :notworthy