02 Estate TDCI,it's started revving up on its own,not all the time tho,goes up to about 2k and sits there,sometimes stops doing it on it's own,sometimes have to switch it off to stop it,ideas please.

Ta
Paul

 

Is it using any oil since this problem started ?

 

as said check oil as turbo could be fucked and the car running on oil and could run on higher and blow the engine

 

ok i'll check the oil,see if its used any,thanx for the replies

Paul

 

Could it be the butterfly flap on trottle body?

 

The flap is only used to starve the engine of air on shut-off to stop it 'running-on'

For it to be revving on it's own it has to be fuel or oil getting into the cylinders.

 

Hasn't done it since I checked the oil,I'll check it again at the weekend to see if it's using any or not
Ta
Paul

 

Wouldn't it smoke as it was revving high if it was running on its oil? Revs up to about 1800 revs and sits there,not done for a week or so but did it 3 or 4 times today,no blue smoke tho,get black smoke when the engines working hard tho.

Paul

 

Soon as it does it take the key out to see if it is running on its own, if it goes straight off then theres no problem with it running on its own lube, probably a throttle pedal problem.

 

Doesnt run on when switched off when revving,ebay it is for an accelerator pedal then!!,any other issues that could cause the revving up?
Thanks for the replies

Paul

 

I've only ever seen the throttle pedals on these fail to cause lack of acceleration, ie car will start, but only run on idle.

Inside the throttle pedal you have 2 sliding potentiometers (APP1 & APP2) basically one sensor goes from 0-5v the other goes 5-0v depending on throttle position and the outputs are worked out by the PCM to give the true pedal postion..

They do this to stop there being any chance of a 'run-away' situation where the engine can rev on it's own.

If any of the APP sensors fail the PCM will only allow a certain amount of torque to be produced, as I say, usually if the pedal fails it will only allow idle speed.

Happy to be proved wrong of course.