Hello guys,

Any ideas................. RS 500 running rough when cold, won't rev and hunting.
Once engine is warm, runs pretty much perfect.
Any ideas other than coolent temp sensor??

Cheers guys

Dave

 

i'd put my money on the coolant sensor although, when they bugger up its normally the other way round

its going to be sensor related

 

ICSV?

 

Yup have you tried disconnecting it?

 

Not tried disconnecting it yet. Is this a common fault with these??

 

mine does this, changed every sensor apart from the iscv, when its disconected its much better

 

would taking the sensor out and giving it a good clean help?

 

The CTS ideally should be chnaged every few years, as it is so important and is the major governing factor for CO.
They cannot be cleaned as they are a sealed unit, the fact that it is ok when up to temp suggests CO is a bit weak when cold, this won't be due to a duff iscv, as all this does is raise the revs, it has no control over mixture.
I would put in a new CTS, then adjust to around 2% -2.5% CO, or what it likes best, if it is chipped seek the advice of the author of the chip.
tabetha

 

I suspected an inlet leak when one of my cars did what you described but it turned out to be the ISCV. Inlet leaks can disappear once everything expands when hot so that's the way my mind went, with a 500 there are a few places for it to do that I guess.

ISCV was cleaned by specialists Promax (Geoff Dewitt's old team) and the nut loc tighted back on but I didn't trust it so replaced it (didn't want anything falling off and into the engine). It did make a world of difference but as Tab says sensor could be sending the CO2 all over the place.

Am still running the replacement ISCV 7 years later and the problem has never come back... but its a cossie so one day it will - lol