Had problem with a too-high idle a few weeks ago. This one was easy to diagnose. When the idle was too high...which was most of the time.... a quick jab at the throttle would restore normal idle speed, suggesting a mechanical problem. A simple process of elimination revealed that the problem occurred only with the throttle cable attached to the capstan.

Ordered and installed a new cable (Jaguar) and the problem was solved....and has remained solved. The old cable had a 'hitch'.

But......

The new cable, seemingly identical on cursory inspection, is apparently slightly longer than the original because, no matter how I fussed with adjusting, I cannot get the kickdown to work. It worked with the old cable. There isn't enough 'pull' for the little bump on the cable to actuate the kickdown switch. The only way I can make it work is to adjust the WOT stop on the capstan wayyyy inward which prevents the throttles from opening up all the way. Not much point in having an operational kickdown if the throttles fall 20% short of fully openinng.

I was slightly suspicious when the Jaguar parts catalog listing shows the same cable as used on the V12 E-type. (Bear in mind I have a V12 sedan, not an XJS). I think the inner cable is a bit longer even though, as stated, the two cables look the same at first blush. I think someone at Jaguar goofed....or whoever makes the cable for Jaguar goofed.

I tried operating the kickdown switch from the full load switch....which actuates at about 75% throttle. That's a bit too agressive; kickdown comes too easily. I had this arrangement on my XJS years ago and thought it was great. I guess I'm mellowing with age....and, besides, my 3.31 diff adds extra response so that an aggressive kickdown really isn't needed. Still, I'd like the kickdown to be operational.

I'll have to do some mulling on how to get around this.

Cheers
DD

 

Do you still have the old cable? If you go to a better bicycle repair shop or marine supply place they might be able to replace the inner cable and put the appropriate ends on it and make it to the exact length you need.

 

Still have the old cable. A new inner cable sounds promising....but I wonder if the kickdown 'bump thingy' might pose a problem. Maybe I'll take the old cable apart for a look-see

Cheers
DD

 

 

It's a cakewalk, Just disconnect it a both ends, remove, replace. The work under the dash is a little cramped but you're not under there for very long. At the pedal end there's a little cotter pin to deal with...no big deal unless you're all thumbs like me

Cheers
DD

 

 

If the cable in binding here's no adjustment that will fix it. None that I can think of, anyway.

You could try lubrication....and hope whatever you're using reaches the trouble spot. Generally, though, cables are meant to operate dry. Lubrication tends to attract dirt. That what Gramps told me, at least.

Cheers
DD

 

 

I have no idea what engine or anything you have, but have you tried cleaning the throttle body? It could be gunk that has collected on the butterfly.

 

 

Maybe check the return springs on each throttle body. The turntable return spring may snap that back on it's own but not have enough strength with cable attached. From memory they need to be installed right way up to avoid fouling the throttle mechanism.
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