Morning all.
Just setting the throttle linkage and noticed when turning the capstan with the ignition on I can hear a click from what I presume is an injector firing but only with a quick turn. Twisting slowly no clicking. Is this correct??

Rob.

 

It is. In fact a sharp opening of the capstan as you have done is a good test that the injection system is working.

 

Chers Greg. You’re a star.
Rob.

 

All done and very carefully set up with the help of Greg and Grants notes. First thing I notice is it starts on the button no cranking a couple of times. Second thing is the cold idle is faster now at 1000 rpm before around 800. Just got to go for a spin and see how she performs. Report back in a bit.

Rob

 

Well done mate.

Once again, SIMPLE cars these V12's, once Freddie Fiddler is banished.
All those little adjustments and tweaks that have been missed for so many years, now done, its a sweet thing.

 

Right been out for a spin. Now a lot better with the hesitation. Pick up is definitely better. Hot tick over was too high at about 1000 rpm. I did notice when pulling up for a junction the tick over revs did jump about a bit only noticed it once. Now home and reset the tick over to the correct 850rpm. I have also noticed on occasion that the tick over revs do waiver very slightly. I do wonder if a lot of this is the lack of use. I noticed a few years ago when I had my Triumph Stag that the more I used the car the better it drove. I need to get more miles on the Jag but it’s difficult when I work full time.

Rob.

 

An absolutely consistent, buttery smooth idle is a thing dreams are made of . Darn few are lucky enough to have it.

There might be an identifiable, correctable fault.

Or not.

Jaguar was well aware of "idle instability" problems and, over the years, conjured up various schemes to address the issue....with perhaps some success.

As for lack of use contributing to the problem, yes, it can. As can too-gentle use. Get the car out on the road and bury your foot right into the carpet a few times. When you no longer see a cloud of exhaust in your rearview mirror, you're done. I can virtually guarantee you'll be rewarded with a better running engine. My Jag (also V12) is my daily driver and sees 97% city driving. Whenever something feels a bit off I give it the Italian tune-up treatment. It always helps.

Cheers
DD

 

Hi Doug. Thanks for your replies to the thread and as always very much appreciated. I think a dam good thrashing in 2nd gear is the way here in the UK other I can see me ending up in court. The tick over I won’t worry about as the waiver is only very slight. I’m going to start another thread on heat soak as I know you have posted quite a lot cooling etc perhaps you will let me have your thoughts.

Rob.

 

Use first gear, boot to the floor!

Cheers
DD

 

🤣🤣👍👍

 

Hi Robbo

I tried that once and it Scared the Hell out of me!

But I do remember Reading in one of the Jaguar Guides, in their Typically Understated Fashion:

That it is not Recommended doing over 100 MPH in 2nd Gear for any extended period of Time

And in a way that kind of made my day, as one minute you can be Wafting along but if you put your Foot down, She Can Hammer down the Black Top like a Wild Thing!

 

Robbo
It will do the car the world of good. These are strong engines and drivetrains, they need a good workout. Place the stick in 1st, the TH400 in the XJS will automatically chnage into 2nd (even if the stick is in 1st) at about 5,500 rpm (about 60 mph). Keep you foot hard down and once in 2nd move the stick to second. It will now stay in second regardless of revs until you move the stick to 3rd. Once you are about the ton in second move to third and give the car a breather.
Doing this every time you use the car ensures a perfect engine! Even if this is not possible, REALLY fierce acceleration in first and second does the job nearly well!

 

I had something like that. The only difference was it was hot and with a full tank of fuel.
The problem was with the fuel tank vent valve.
Fuel fumes were sometimes very high with the pedal to the floor.

 

I tried this twice today and couldn’t get it to drop into 2nd. However, trying was fun. 2nd attempt I brought it to 6k rpm before getting a bit anxious and manually moving to 2nd gear.