J-P

Hi! Car is a 1988 RWD Sapphire cosworth.
I got the car with an unlinked ICV and the mechanic told me not to link it. No problem with the exception of cold start that can be painful, running fine when warm, base idle 900-950.
The ICV is a VAE01.
I ordered a new one on the net, and I received a VAE06. It looks quite different from the old one, with a long spring and a plastic wheel against the nut. On cold start the engine jumps up to 2000 rpm for a few seconds, then drops dramatically down, even stalling most of the time. When hot, the engine is hunting badly, until I disconnect the ICV when it gets steady at base idle.
Any clue appreciated!
J-P

JonathanJ

I use Intermotor's web site to cross reference stuff like this it states that VAE06 is the correct one for Cosworths .

Also found this

http://www.worldcarparts.co.uk/CarPa...3/Default.aspx

Which would suggest that the 2 part nos are interchangeable

I know that does not help the fault , but should remove the doubt that the ISCV is at fault , rather something else around it .

J-P

Thank you, already a piece of the puzzle...

dunketh

When hot:
Car was fine with old ICV, not fine with new ICV.
Disconnecting new ICV makes car run better?

Hmm, taken in isolation that points to a duff/incorrect sensor imho.
I have no cossie or electronics experience, just going by what you've said.

Of course I'm conveniently ignoring the cold-start problem - but this could be a different issue with a different cause, given the new sensor failed to address it.

tabetha

I would firstly if it's a new to you car, change the CTS then set the CO to around 2.5%.
tabetha

J-P

Dunketh, thank you for helping.
Old ICV was disconnected.
Yes, disconnecting the new one makes car run better.
And cold start is getting worse with the new sensor.

Tabetha, thanks.
I have that car since 1999, and everything was fine until the ICV got stuck. Ford's racing mechanic told me not to bother and just disconnect it.
CO is 2%. Does the CTS activate the dashboard display, or is it a computer link only?

martysmartie

iTrader: (1)

As said something is telling the ISCV to do this, I would be checking the TPS calibration and CTS.

The CTS sole purpose is to provide the ECU with temperature info, it has nothing to do with the temperature gauge, this has it's own sender located on the exhaust side of the head at the front on 2WD.

Disconnecting it is not a solution and it is needed otherwise it woulden't be there in the first place

Martin

J-P

The electrician checked all the available values, no problem.
But, I remember that the car had been in a garage for a precautionary belts change, and therefore they have to remove the boost hoses, so I checked them and the intercooler to throttle housing one had a leak... I fitted it better and now, at least when warm, no more hunting, 950 rpm idle...
I'll check this evening with a cold start.
Cheers.

martysmartie

iTrader: (1)

Keep us posted, incidently there is no need to remove the hoses when changing the belt.

Martin

J-P

Well, I don't know how you could change the power steering belt without removing the hose, same thing for the alternator, or maybe from below?
Anyway, the hose was well fitted when the car got into the garage, and had a leak when it came out, hence my assumption!
I'll certainly keep you informed, thanks for sharing.
J-P

J-P

Still badly hunting on cold start...
I will try to borrow a CTS and check. I guess it is the blue one nearly impossible to reach without letting part of your skin there!

martysmartie

iTrader: (1)

CTS is difficult to access it's on the rear left hand side of the head, as to the belts all are replaceable without removing anything else (I have done it) I did from below as this is the easiest way.

Have you checked the TPS calibration?

Martin

J-P

Hi all, here is a message I received from the seller:

"Hi

You need to adjust the idle by moving the spring down. You can move the spring down by moving the nut down.

Regards"

I thought we were not supposed to touch the nut!
Opinions?

JonathanJ

Thought the nut was loctited on to the shaft , and you did not touch it , would not want that nut coming off and going for a wander into engine ....ouch.......I always adjusted the base idle with the air bleed screw , different people have different ideas how to do this , I always did them hot with no load on and fans off to about 850 , then the ISCV only comes into play for cold start and other load situations like fan on , make sure TPS is calibrated correctly and someone has not adjusted the base idle using the TPS as the back stop for throttle plate, go back to basics , check each sensor for correct base readings , would offer to came and have a look but it is a bit far

martysmartie

iTrader: (1)

I have heard the above as well, apparenty if the nut is interferred with it may work loose and fall off and into the engine!

If it's hunting with ISCV, then something is telling the ISCV to act in that way!

Martin

J-P

I rest my case...
One day at the electrician checking everything without results and another day at a garage, no result either, a lot of fiddling here at home and no result...
The old valve is back on the engine and I have a costly weightpaper... LOL
Cheers
J-P