Jaguar World Monthly Forum - High Idle 95 xjr

2jagsDoug

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Re: High Idle 95 xjr
Reply #15 - 27.04.2012 at 13:44:09

Rads wrote on 27.04.2012 at 10:33:47:

Thanks for posting the follow-up; it is always good to find out how faults are ultimately resolved. My car also suffers high idle but I think it is mechanical ie sticking throttle. I have got a new throttle spring; these were uprated, but the process of replacing it on the supercherged car looks complex!

There are two return springs, a linear spring on the external linkage and a coiled spring on the throttle body itself. As i recall Jaguar uprated both of them.

The linear spring can be removed fairly easily from below...probably easier to wait until your next oil change as removing the oil filter gives a bit more room to work.

It can also be reached from above but you'd probably have to remove the cast elbow from the intercooler/inlet manifold.

The one on the throttle body itself requires that the t/b be partially diassembled, I think....which means removal from the car, of course. No easy task.

Quote:

After the insulation fell off the wires to the traction control throttle servo I dismantled same while replacing wires and found the mechanism to be dirty, slighly rusty and sticking. This may have been affecting the throttle closure. Haven't started it yet so cannot verify any change.

Good to know. It gives me a reason to take a closer look at mine.

I'm not having an idle problem at the moment but I do think I have traction control problem.

Any tips on dismantling/reassembling the unit? Or is it all slef-evident once you dig in?

Cheers and thanks
DD

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Doug Dwyer
Longview, Washington USA
1995 XJR

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Rads

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Re: High Idle 95 xjr
Reply #16 - 03.05.2012 at 08:06:36

2jagsDoug wrote on 27.04.2012 at 13:44:09:

Rads wrote on 27.04.2012 at 10:33:47:

Thanks for posting the follow-up; it is always good to find out how faults are ultimately resolved. My car also suffers high idle but I think it is mechanical ie sticking throttle. I have got a new throttle spring; these were uprated, but the process of replacing it on the supercherged car looks complex!

There are two return springs, a linear spring on the external linkage and a coiled spring on the throttle body itself. As i recall Jaguar uprated both of them.

The linear spring can be removed fairly easily from below...probably easier to wait until your next oil change as removing the oil filter gives a bit more room to work.

It can also be reached from above but you'd probably have to remove the cast elbow from the intercooler/inlet manifold.

The one on the throttle body itself requires that the t/b be partially diassembled, I think....which means removal from the car, of course. No easy task.

Quote:

After the insulation fell off the wires to the traction control throttle servo I dismantled same while replacing wires and found the mechanism to be dirty, slighly rusty and sticking. This may have been affecting the throttle closure. Haven't started it yet so cannot verify any change.

Good to know. It gives me a reason to take a closer look at mine.

I'm not having an idle problem at the moment but I do think I have traction control problem.

Any tips on dismantling/reassembling the unit? Or is it all slef-evident once you dig in?

Cheers and thanks
DD

The tc throttle valve actuator is not a complicated thing but if you disassemble it I would recommend that you mark the position of the position feedback pot on top so you can put it back in the same position, and the lower gear is spring loaded with a clock-type spring so make a note how much it unwinds when you lift off the quadrant gear (so you know how much to pre-load it when you reassemble). Also be careful when you lift the lower gear as that clock spring will want to escape! The motor is staked together (I think that's the term) rather than having screws so I did not try to dasassemble that, just sleeved the wires.
Rads

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2jagsDoug Senior Member Offline Posts: 1456 United States Gender:	Re: High Idle 95 xjr Reply #17 - 03.05.2012 at 14:18:36 Thanks for the advice. I'll add the project to my "to do" list Cheers DD
Back to top	Doug Dwyer Longview, Washington USA 1995 XJR IP Logged