kishy's 1992 Jaguar Sovereign

[kishy]

I have descended into madness.






This is a 1992 Jaguar Sovereign, which is a high trim distinct model of the XJ40 platform. It is powered by a Jag AJ6 4.0L inline 6 gas engine, with a ZF automatic transmission (I believe 4HP24), and is rear wheel drive. It has 51,768km showing on the odometer, and has been sitting in storage which recently kicked the car out, causing its sale. The mileage is very believable and I'd be rather surprised if it's been winter driven.





I have long liked the XJ cars, of all generations from all iterations of the Jaguar brand under all of its various parent companies. I believe this is a Ford-era car in terms of when it was built, but it was engineered well before that. I have long said I'd like to drive one sometime. This turned up on Facebook Marketplace for a little too much money to be a frivolous buy, but not unreasonable if it turned out to be a clean car, so I went to check it out.







I neglected to take any underbody photos but it is in excellent condition. I haggled a bit, found the seller to be pretty firm at $2500, and I agreed the car was worth it so here we are, the second most expensive car I've bought yet. This stings only because the car does not presently run - the ad included a video showing it running (and smoothly), but the seller confessed that after several showings, the fuel level ran low and the car stopped running. Adding fuel from a gas can did not revive it. So, I took a small gamble that it may be something worse than a fuel pump but hopefully is only that. Also, the ignition lock cylinder is seized and presently removed, but the keys received with the car do operate all of the other locks so I'm hopeful that I can un-seize the ignition cylinder.



I did buy the car a battery. It takes a group 47, which doesn't seem to exist anymore, but the seemingly identical H5 does, so it got one of those from Costco. I also brought it a bigger gas can full of its required premium gas, but unfortunately the starting issue does persist. The very first time I tried, it did start and idle quite roughly, then died. I do suspect a fuel issue and at no point do I hear a pump run, though it's not clear to me if I should be able to hear it. I located the fuel pump relay, found the wiring into it is a little green but not severely, swapped the relay for another, and had no change.

The plan for this is similar to the Acclaim, but with decidedly less commitment I think, since that went insanely off the rails very quickly. I'd like to get this running, drive it a bit, and evaluate from there. I am not removing its engine. I am not removing its transmission. I'm sticking to reasonable things with this one - fluid changes, perhaps a couple gaskets and seals but no serious surgery, maybe some wheel-end stuff as required, but then just drive it. If I fall in love, then commit to going insane with it, but if I don't, sell it for whatever I have into it by that point, and move on.

[Arquemann]

Now that's a proper Jaaaaag.
I fully support this descent into madness!

[friskyfrankie]

Wonder what the price points for parts would be?

[sly]

One thing I do know, you must keep a stiff upper lip when dealing with a Jaaaaaag.

[kishy]

Hmm...good question.

A couple quick checks on RockAuto tell me that belts, hoses, thermostat, filters, brake pads, motor mounts, the fuel pump, temp sensors, ball joints, tie rod ends, oxygen sensors, power steering hoses...all compete with the Panthers for pricing. There are probably Jag owners who would cringe at the thought of buying non-dealer parts so perhaps there are lessons to be learned here. Perhaps by me, or perhaps by them.

However, some items are a little more exotic. Throttle position sensor? 340 USD. Perhaps it never ever goes bad.
Air flow meter (or MAP sensor, I don't even know what this system uses yet)? Seemingly not produced aftermarket.
The car also has Teves III brakes with the electric pump and accumulator design in place of a vacuum booster or hydroboost unit, which I understand to be expensive to deal with if it has problems.

The problem I grappled with in deciding what I'd be willing to pay was how much I'd be willing to lose for the sake of simply getting to experience the car. It's in remarkably good shape, and (as I reasoned with the Acclaim) that is the aspect of the car that I cannot address myself. It's either nice or it's not, rusty or not, straight bodywork or not - and those aspects of it are the things that made me willing to take a gamble on it, despite definitely losing that same gamble on the Acclaim. But the balance of risk/reward seems favourable on the Jag because the potential for how good it could be if all the stars align properly is a substantially better car.

Some further reflections on the no-start:
The dash has a computerized diagnostic thing, called VCM for Vehicle Condition Monitor.
It will read out various codes in the odometer display for assorted problems.
The only problem it identifies is "Fuse 1", which is not a fuse number but instead implicates a blown fuse in a specific fuse panel. The car has several.
I had looked, and been unable to locate any blown fuses. But it may be that simple. The car had a completely trashed battery in it and was being started on a booster pack. Low voltage can mean high current on a load like a fuel pump so perhaps it just popped a fuse.

I'm going to return to the car equipped to try to get the fuel pump to go - test leads, meter, fuses, mallet. If power is getting where it needs to go and the pump is indeed dead, that'll kind of suck. Since the VCM is capable of diagnosing a fuel pump circuit problem and isn't doing so, I do believe the pump is the issue presently.

[Tynnerstroem]

What a mega-cool purchase, nice! Always loved the look of the big Jaguars.

[gadget73]

I thought I recognized that accumulator ball. Its not identical to the one on a Mark VII but its an extremely close relation. The Mark VII got the Teves Mark II.

Some specific words of advice about that system, flush the brake fluid. Its very expensive to repair if that unit fails, so you don't want wet fluid in there to cause you grief. If the pump kicks on every pedal application, the bomb is bad. You should get at least 2 brake applications. If it gets real bad, the pedal will get very hard each time you try to stop until the pump kicks on and makes some pressure. Thats the point where its both dangerous and abusing the pump. Accidents and pump replacements are both expensive. Been a while since I bought an accumulator but they were a couple hundred bucks.

Is this an in-tank pump or an external hanging under the car?

Looks like mass air but it could b an air flow meter rather than the heated wire setup. An AFM is basically a plastic flap connected to a variable resistor and they are prone to wearing out.

I've heard the Jag I6 is actually a very good engine, never experienced one myself.

[kishy]

What a mega-cool purchase, nice! Always loved the look of the big Jaguars.

Thanks! Aesthetically I prefer the prior XJ cars, but as I understand it, this one will be easier to live with.
I could do much to fix my dislike of its looks by swapping it to the lower trim headlight treatment - the higher end cars (Sovereign, Daimler) got the rectangular beasts that this car has, while a car sold only as an XJ6 would have the round lights with a bezel.

I thought I recognized that accumulator ball. Its not identical to the one on a Mark VII but its an extremely close relation. The Mark VII got the Teves Mark II.

Some specific words of advice about that system, flush the brake fluid. Its very expensive to repair if that unit fails, so you don't want wet fluid in there to cause you grief. If the pump kicks on every pedal application, the bomb is bad. You should get at least 2 brake applications. If it gets real bad, the pedal will get very hard each time you try to stop until the pump kicks on and makes some pressure. Thats the point where its both dangerous and abusing the pump. Accidents and pump replacements are both expensive. Been a while since I bought an accumulator but they were a couple hundred bucks.

Is this an in-tank pump or an external hanging under the car?

Looks like mass air but it could b an air flow meter rather than the heated wire setup. An AFM is basically a plastic flap connected to a variable resistor and they are prone to wearing out.

I've heard the Jag I6 is actually a very good engine, never experienced one myself.

Yes, this system should work essentially the same, as I understand it.
After sitting overnight, it did run the pump when I first visited it today, but it seems to give a couple pedal applications before it runs again.
I have tons of ATE DOT4 hanging around and I do plan to flush it as this is a widely, commonly made recommendation for keeping it working well.
Trivia you may have known: the T in ATE is Teves, for Alfred Teves. They are the same company.

As best I can tell, there is one pump, and it is inside the tank. There are many references to a possible external pump but I do not believe this year and/or engine received that arrangement. But I'll have to look at it more closely to be sure.

--

So, after work, I collected some items I'd need to verify the fuel pump diagnosis, and went to visit the car. I had charged the new battery overnight so it would be ready for more cranking without success, in case that happened.

First, I checked the fuel pump inertia switch. Yes, it has one. It is a Ford era car and I believe it may be a Fordism.
The switch did not appear to be tripped, but I smacked it to make it trip, and then clicked it back down again, to exercise its contacts.

Then, I verified power at one of the fat wires on the fuel pump relay. There was power present.
Then, verified that the other fat wire on the fuel pump relay becomes hot for a couple seconds, then turns off again, when the key is turned to run. This does happen.
So, we know the computer is commanding the relay on, and the relay is passing current.

While doing that, noticed that I heard a distinct "fluid-ish" sound from the engine. It is a sound that I could believe is fuel squeezing through a pressure regulator into a return line.
Repeated key cycles to prime the pump repeated the same noise.
I checked the pressure regulator vacuum port and found it dry, which is good.
There is no pressure test port on this system and opening it with a wrench would have been messy so I opted not to do that.
I tried to start it, and found it sputtered to life, would not gain any RPM with the pedal, and stalled quickly.

I looked at the distributor contacts and they looked OK.
I then opened the air filter box. I couldn't get it open enough to actually see the media side of the filter (or, for example, to see if it was full of mouse nest), but I was able to create a gap allowing unfiltered air in.

The car starts and runs! It has a bad miss on at least 2 cylinders, but when it's brought above idle it runs pretty smooth but won't hold a constant RPM. This does sound alarmingly headgaskety to my mind, but the oil isn't milkshaked, there is zero smoke, the exhaust smells about right aside from a hint of unburnt fuel. Compression test will be a priority. I will note that with each subsequent restart it has ran better and better.

I popped it in drive and took it around the parking lot. I managed to verify that it moves under its own power both forward and back, and seems to have at least 3 of its forward gears, with shifts that felt confident. Sweet.

Headed directly for a U-haul location and rented a pickup and trailer. Promptly collected the Jag and delivered it home.







Drove onto and off of the trailer without incident. Definitely not running right, but is running.

[Mainemantom]

That Jag is a nice car. Very expensive to fix with Jag only parts. Have you check the fuel filter ? We know people that have that model with the lower trim level. It is a nice riding, strong running car. Once you understand the car, you will like it. Electrical problems abound as you have started to see. Very good buy for the money. The paint seems nice too.

[gadget73]

might just be fresh fuel and some of the usual maintenance crap will get it going again. Can't be that horribly broken if it runs enough to move onto a trailer on it's own.