Air idle control valve on supercharged 4.2 V8

[simonjrwinter]

Does this engine have one of these fitted?
Thanks
Simon

[8bit]

Can't find any reference to such a thing in the workshop manual for the X150 XK/XKR 4.2 but there were subtle differences in the 4.2 in different models. Which car is/was this engine (originally) fitted to?

[simonjrwinter]

Sadly I don't know. It's fitted in a Cobra replica and while the ECU has been fully mapped and the car set up on a rolling road, I need to address some cold-start issues in the software......first question in the manual is, does it have a AICV!
Simon

[8bit]

OK, how many intake pipes are there feeding in to the supercharger, one or two?

[simonjrwinter]

HMMMMM, pretty sure its just the one

[8bit]

Not sure if this will help - http://www.jagrepair.com/images/Training%20Guides/...

I'm by absolutely no means an expert but from what I can make out in that document it doesn't sound like there is such a valve on the 4.2 V8, sounds like it's done electronically.

Some further googling shows a post on jaguarforums.com about a 3.0 S-type which was giving fault codes regarding the air idle control valve, I guess if there was one fitted to your engine and it was the cause of the problem then you'd likely see a code about it.

I was going to suggest you post on jaguarforum.com but I see you already have You're probably in the best place you can be for help there to be honest. If it were me, my first stop would be at a good, reputable mapper local to you.

[Dodsy]

Ask on here - ok its not a Jag but its an X350 engine and the guys on this forum are very helpful and knowledgeable

http://www.jaguarforum.com/forumdisplay.php?f=32

[melhookv12]

No idle control valve on v8 engines. Is it still using the jaguar throttle body ?
The Jaguar throttle body was electronic, which I believe controlled idle speed via ECU and engine speed sensors.

Also we need some pictures of the installation and specs please !

Edited by melhookv12 on Wednesday 9th March 21:39

[Piersman2]

Not sure if this will help... as I'm not entirely if I understand your question, however...

The supercharger used on the 4.0 and 4.2 V8s has a bypass valve as part of the supercharger intake system which is controlled by the vacuum. When the car is idling it bypasses the supercharger intakes to effectively turns off the supercharge. Once you hit the throttle and the vacuum prsessure rises it changes the valve state to allow the intake air to flow through the supercharger to be compressed.

I think the 5.0 supercharger does the same but not sure if it uses vacuum or electronic control, the supercharger on the 5.0s was a significantly different version than the ones used on the 4.0 and 4.2, IIRC.