Hi, if you have an XJS, this is the book for you.
Free download, 700 pages, covers everything.
Kirby Palm's Jaguar XJ-S Help Book

 

Great ideas. I think I will try jumping the inertia switch (impact cutout) and see what happens.
I found this and if is anything like the Jaguar's then it is plausible:
Ford Ranger/Bronco II Inertia Switch

 

Ok. Took it out again for a big drive. All ok UNTIL I put my foot down and then it just cuts out intermittently. So I really think it is a fuel problem.
BUT... if whilst cruising, I put it into neutral and put the foot down, it revs beautifully without cutting out.
Put it back into drive and it cuts out under acceleration/load.
So it only cuts out under load....what could be causing this fuel problem?
Thoughts? Thanks. Rod.

Might try this;
FUEL SUPPLY CHECKING: It is often useful to know if the fuel supply to the injectors is working properly. To do this, Robert Dingli suggests installing a fuel pressure gauge: "I bought a VDO fuel pressure gauge for about Aus$40 and connected it to the fuel rail where the cold start injector was once supplied. I believe any pressure gauge designed for hydrocarbons would be suitable and other brands sell for much less. My gauge is mounted in the engine bay as I am paranoid about high pressure fuel entering the cabin.
"There are a couple of things to note about connecting the gauge :

• use high pressure fuel line and fittings.
• don't mount the gauge on the engine as vibration will kill it.
• use a restrictor in the line as the pressure fluctuations will also kill the gauge."

 

Can someone please explain simply the fuel system. I think I've found the inlet and outlet fuel regulators. What is the connector on the left fuel rail with two vacuum hoses onto it?
Any diagrams or pictures? Thanks. Rod.

Thinking out loud.....Because of all the vacuum lines and the car dies when the throttle is opened up, could I have a leaking vacuum hose?

 

Are you sure those are vacuum hoses? There is a cooling device that has two lines from the A/C attached to it on that side...

 

You may have a fuel pressure problem. You need to install a gauge in the fuel system. Since your problem is only under load you need one with a fairly long hose. Then snake it out from under the hood and tape it to the windscreen. Then drive the car until it happens. If the fuel pressure drops that is you problem, if not then look elsewhere.

 

I'm tending to think it is vacuum (fuel pressure regulator) problems.
I've replaced the fuel pump and as stated when NOT under load it revs out beautifully. But under load, when vacuum is normally reduced (I think), I think mine may not be sufficient due to a leak.

 

Did you check your TPS?

 

Sorry, can you expand on this, please.

 

ok gurus. Work this out. Just took it for a drive and it worked like a dream. No sluggishness etc on acceleration. BUT wait....
The automatic kickdown worked too. First time since I've owned the vehicle.
So...tell me how these two things are related???

Now all I need to get working is the cruise control!!!

 

check your Throttle position sensor with a multimeter. it should read ~ .35v at idle and ~ 5.0v at WOT.

theres a connector coming out of the throttle capstan. check it at the red and yellow wires.


and kickdown is easy to adjust. so what happened between running like crap and running smoothly? did you do anything to it?

 

Normally, I'm very gentle with engines and literally not go over about 1,500rpm until they are warmed up.
However, when this happend, the car had only driven less than a kilometer and there was a bit of open road, so I put my foot down and I couldn't believe that for the first time the kickdown operated and no hesitation.
Doing another run in a couple of weeks. (I don't use it as a shopping car and only take it out on runs of about an hour or more).

 

There is a fuel load enrichment enrichment switch that is on the throttle and a vacuum operated one. It is to enrich the mixture under heavy load. There are two wires on both and they are wired in parallel. Wire colors are black and white/slate.

 

HAHAHAHAHAHAHAHAHAHAHAHAHAH!!!!! Oh, boy, thanks for that. I needed a good laugh.

Anywhoo, M90 described how to check the TPS but it sounds like that's OK so don't worry about it.

I wonder if you had some carbon fouling on the valves and you finally blew it out by taking it for a few WOT runs?

My kickdown thingy was siezed up when I first bought my car, it took some doing to get it unstuck. It's got no relation at all to fueling or the issue you were having though, it's very simple and basic, just a switch on the throttle cable. Again, sounds like you just worked it free.

If you're lucky, you're just blowing the cobwebs out!

 

Ok guys. Out again today. All systems seem to be working really well. No hesitation on acceleration. I guess my "blowing the cobwebs out" worked.
The other thing I've learned is for the kickdown to operate, it really has to be floored. Found description of operation and saw it for myself on engine.
However, I have read that the kickdown can be re-wired into the fuel enrichment microswitch so that kickdown operates a lot sooner. I seem to like that idea. Thoughts? Rod.

Just found this;
The original kickdown switch, which works only if your foot is completely buried in the carpet, is abandoned. The switch used for fuel enrichment, however, closes at about 3/4 throttle. I used voltage from the enrichment switch (white/slate wire, as I recall) to energize a common accessory rely which, in turns, operate the kickdown circuit. The wiring would be like this:

Terminal 85 of relay: ground
Terminal 86 of relay: voltage from white/slate wire
Terminal 87 of relay: green wire from kickdown switch
Terminal 30 of relay: green/white wire from kickdown switch

Some minor wire extending and splicing is needed, of course.

The kickdown will now come in much sooner and no longer requires full throttle. Gentle drivers might find it a bit too aggressive...but gentle drivers probably won't be reading this

The now unused original kickdown switch can be used as a full-throttle A/C compressor cut-off by wiring it into the compressor relay circuit

 

Hi Rod did you go on the JDCA run to Mittagong?

 

Hi Warren, Went to the National Motoring Heritage Day at Mittagong Public School. Numerous Jags there who may have been part of the JDCA. Top day. Very surprised that the public did not attend. Apparently it was not advertised. I would have thought that this was the BEST day to get the public involved in heritage vehicles. Rod.

 

I went to the start point at Leo's but did not go to Mittagong. Hope it was a good day. Once I get my XJS on the road I will start frequenting the JDCA runs

cheers

 

HI Warren. I've tried a few times lately to access
The Jaguar Drivers Club of Australia

The Jaguar Drivers Club of Australia

but for some reason, won't connect. Have they changed servers?

 

I can vouch that it works.

In fact, I wrote those directions :-)

Cheers
DD