Did you ever get an answer? I have the same issue with my 89 XJS.

 

Very common issue. My experience is with a coupe....not sure how the tanks/plumbing differ but....

You may not find actual drips. Often it's a matter of very slight seepage from various sources. In such a confined area it doesn't take much to create a very big odor problem.

One leak tracing trick passed to me was to wrap all joints in colored tissue paper. Even the slightest dampness will discolor the paper.

In most cases replacing all the hoses does the trick. A couple of the metal fittings have o-rings as well.....you'll have to look at a parts diagram for your exact model.

Sometimes...fairly often, actually... the tanks themselves leak. Again, it only takes a very small seepage to create a problem. Besides rust-out problems, some suffered from a rub-through leak cause by a rivet head on the shelf where the tank sits. Not sure if that was still an issue on later cars such as yours.

The tank pad and carpeted boot trim hold the odor long after the leak is fixed. I took all the carpeting out and soaked it in the bath tub with a healthy dose of Simple Green. I used a thin piece of closed-cell foam as a tank pad as the replacement from Jaguar is one of those things that's just stupid-expensive....like $300 or something crazy like that.

If I ever own another XJS I'd remove the tank, replace all hoses and seals, replace the pad, etc all in one shot. Get it all over and done with at once rather than fussing with it piecemeal.

Cheers
DD

 

Just realized I answered under the assumtion that your fuel odor was in the boot/trunk even though you didn't actually say so.

If the odor is in the cabin it could be originating from the boot or the engine bay.

Cheers
DD

 

Another source of strong fuel odor in the cabin is a malfunctioning vapor recovery system.

Does your fuel cap make a "whoosh" when you open it? If so, you may need to look at the vacuum lines going to the Rochester valves and the charcoal canisters.

There's is also a documented issue with the tank rubbing a rivet on some cars. That can lead to a fuel smell in the trunk.

 

Expansion and contraction of the tank (due to the retention of pressure via the vent/purge system - a function of the design), can cause fuel tank failure at the spot welds on the bottom of the tank. Indication of this being the issue can be a wetness of the pad under the tank. It's an issue I've seen many times. However, it is also prudent to check the basics and even take 5 minutes to tighten the hose connections in the trunk.

 

Check your fuel rail in the engine bay. In fact I would start there. High pressure fuel leaks can be found around the old rubber hoses and potentially dangerous. Good luck

 

Ok guys thanks. Sorry, was on a break to Afghanistan the past year.
I read many post last year and the year before on this, and just got started on this the past month. Thanks for all the post!

1989, XJS 5.3, convertible, white, blue interior. Smell intense in Boot, been going on since I bought her 7 years ago, no smell in the cab with the top down...... Do have the woosh demise. (Not sure how a vacuumed tank equates to venting in the boot?)

No wetness visible anywhere. Checked all the connections and hoses, no leaks there. More hoses as you disassemble, but no leak suspected.

Pulled the tank today, PIA. Only a spot of rust here and there, just surface rust. No rivet issue. Can't tell if the seams are leaking. No wetness under the tank.

But, the shelf the tank sits on/in, has a yellowish film, most likely old drying up fuel, coating the entire shelf and on over the entire panel leading to the bottom of the spare tire well, definitely not the white color of the rest of the metal in the boot.

Just after ordering some new fillerneck gaskets, and a sending unit.
I'm going to have to address this venting issue as well.

So I am thinking of pressure testing it in the morning to check the seams. So if I find a leaky seam, do I re-weld the seam, solder? silver solder?


Any thought on this from anyone ?? Thanks.

 

Any radiator repair place will be able to pressure test the tank. VERY good idea. I had my local rad guy solder all over the floor and seams of mine and test afterwards over 24 hours. 100% since.

As you have the whoosh you definitely have a tank venting problem, which will be at least half of your fuel odour cause. There is a comprehensive post on this already that I will find and put on here. It is a very good idea in any event replace the under tank mat with some modern neoprene type stuff, and clean out the whole boot before reinstalling the soldered tank. Also the hoses in the book (trunk) may well be going home and it is a very good thing to replace the lot of them. Ditto the over-axle pipes which are fixed using compression fittings and which join the boot out and return pipes to the solid pipes under the cabin floor, via a brass 90° fitting in each corner of the trunk. And the fuel sender rubber gasket and locking ring.front bottom

If you have not yet done so, its a good idea to clean out the sump tank under the battery and change the sock filter inside it and locking ring and rubber on that too. Also do the main filter behind the spare and all associated pipework. You will need new brass olives ot redo some of these fixings into the tank.

Link 1:
http://www.jaguarforums.com/forum/xj...m-work-114102/

Link 2:
https://www.jaguarforums.com/forum/x...actory-116525/

Good luck

Greg

 

when I replaced all the tank pipes I did away with the complex breather system and fitted this pressure relief valve to exit though the floor near where the aerial drains, mine whooshed for 15 years prior to this mod and always had a petrol smell in the boot, I used low permeation marine fuel hose,
this is the valve I used but I didn't pay anywhere near this price buying direct from mocal
Mocal Fuel Tank Pressure Relief Valve - In Line Fitting Motorsport/Rally/Racing | eBay