Just bought the NEW Idle Control Valve Jaguar XJS Vanden Plas XJ6 95 94 92 91 90 XJR 97 96 1995 | eBay
Ill let you all know how it goes after I fit it

 

Thank you Doc-

Hey... one thing I'd forgotten to mention along the way, I "believe" that when I had replaced the battery the car idled really nicely for about 50 miles worth of driving - then the rough idling reoccurred... I'm going to try repeating this experiment here this weekend- I'll let us know how that goes...

But it got me to thinking that it shows it can run smoothly - just not sure why it doesn't stay that way...

Thanks guys!

 

Just fitted the icv valve this week turned out to be a big job on the xjr6 replaced the manifold gaskets and coolant rail also engine mount at the same time
Drove it home about 160 K's drives good I think it goes better as well idle is smooth no more fluctuating or driving itself

 

Give it after days. I've found that fixing idle problems, for me, that part cleaning and swaps SEEM to fix problems only for them to just come back...like the ecu is tricked for a bit and then adjusts and back to the same ole running issues. Just me though and I'm no mechanic.

 

I had the original Idle speed control valve cleaned worked for a couple weeks since fitting the new one it seems to be okay although it does not go back to idle as quickly as I would like might put a heavier or booster spring on the throttle butterfly

 

Since you pulled a lot of stuff off the motor and replaced gaskets, etc., you might want to search for air leaks around the work you did. Slow return to idle might be a mechanical issue but it also may indicate a "lean" drop which is caused by air leaks. Unless this issue was always present which might still mean the same issue.

Cheers
Bernie

 

When the indie did the iscv he took of the whole manifold new gaskets the lot I supplied the valve and it still cost a grand it could just be the way the car is
since buying a X350 couple months ago I have rarely used the XJR6 its on the trickle charger under a cover might take it out on Sunday for a run

 

All,

I need a good mechanic. Live in Atlanta, GA have a 2004 Jaguar XJ8. No problems but want to keep maintenance up.

Thanks

 

Excuse me if this is a repetitive question, buy I just got a '96 4.0 X300 and it has the fast idling thing too.
Also, when I take off, I can take my foot of the accelerator pedal and it's still pulling away.
If I pop it into Neutral, the rpm's will race up to 2,000 - 3,000 rpm's before I pull it back into drive.
When I come to a stop and put it into park, it doesn't race up like that but it idles at around 1,200-ish.
My question, other than how can I easily remedy this, is, what is WDS and TPS calibration and orientation of oxygen sensors.
I know what oxygen sensors are, but how do I get them orientated?
I'm in Providence, Rhode Island and I've asked the German Motors place and another place that works on Saabs and Volvos if
they know of an independent Jaguar guy in the area and they don't.
I can't believe there isn't at least one...

If you get the chance to reply that would be great.
I don't even think there is a Haynes or Chilton manual for this model.
I sure could use something like that.
I can't stand not having a book.
Computers are OK, but I like books.
You get'em wet, you can dry 'em out and they still work.
Not so much with my laptop.

- J. Shelter

 

In addition to the IACV, there are other determining factors.

The throttle spring could be weak or the throttle plate/shaft has 'gummy' deposits causing the plate to 'hang'.
Throttle plate adjusting screw not set properly.

Could also need TPS calibration??

Oxygen sensor orientation tells the ECM which sensors are plugged into BANK 1 and BANK 2.
It does not matter what one is plugged into where if you perform the orientation and let the ECM decide.

bob

 

You most likely need the Throttle Potentiometer Sensor (or TPS) reset.

Anyone with a diagnostic machine that includes Jaguar software can perform the reset...even the dealer. There are many aftermarket machines, such as AutoEnginuity that can handle this.

Before you perform the sensor reset, you will need to clean out the throttle body itself. It is likely very gunked up. If you decide to take this on yourself, there is the possibility of setting the TPS correctly, so you would not need the reset.

When taking off the throttle body for cleaning, you'll have access to the TPS. Take it off, and slot the mounting holes so you could rotate the sensor, ever so slightly.

After cleaning the throttle body, replace the TPS and tighten it down enough that you could rotate it by hand, but snug enough that it requires a little effort, so its not not loose.

Reasssmble, start the car and work the TPS. You'll be doing it in the blind, and by feel, but if you have someone else in the drivers seat, have them wave you off when the RPMs come down to 700 cold, or 600 (or even 580) if the engine is now hot. Then turn off the engine and tighten the TPS down, locking it in place.

 

I just bought an ICV on eBay $11.00; haven't installed it yet due to the location of the lower bolt on a 6 cyl. On older carbureted cars there was an idle adjust screw.
Not replacing the ICV and blocking the hole, could the throttle be modified or set to provide a steady idle speed?

 

In a word, no.
You could try to tension the throttle cable to set an idle speed, but it would not be dynamic enough to cope with cold starts and the engine slowing after throttle lift off. The ISCV isn’t such a big problem on normally aspirated cars, and the real issue on supercharged cars is access rather than the valve. You would have to overcome the access problem to block the hole, so I don’t think it makes sense there either.