1988 XJS Charcoal Canister


Tank is back in and i assumed they would replace the mat…will pull the spare tire tonight and check, if not replaced I will take it back and make them do it. I would never try to pull the tank myself. Still going to pull the back seat and sniff that yellow pad…if soaked i will pull it out and clean really well…stay tuned.


(Greg) #44

I would think if the tank had a leak, it would be the bottom (mine was). And unless you parked facing downhill, it would leak out the back into the trunk (mine did).

They may have fixed the tank leak. Are you sure all the hoses and connections back there are leak free?

Do you only smell gas in the back seat, and not the trunk? That is odd.

Gasoline evaporates fairly quickly, so I would think after a week, you should not smell gas vapor unless there is still a leak.



Yes I"m hoping it will evaporate.
I just had a thought…how about something as simple as the gas cap?
Can’t find any like it online OEM with door key lock, so is it ok to use one from Autozone to test?
still going to do my best to scrub away the carpets and back seat area this weekend.
Found out my shop took the pad out under the tank, cleaned it and set it in the sun for a day.
Wish they would have just replaced it, but tank is back in for now…too late.


(Douglas) #46

Let the whole car air out as much as you can. I think Greg is right that the smell will improve if leaks are gone.

There are a lot of connections to the tank in the XJ-S. It might be worth going over all of them yourself to make sure that the shop hooked everything up properly and leak-tight. After doing the entire tank/fuel line replacement myself, I was glad that I took my time with the project. It meant my car was parked a bit longer, but also that I personally, carefully inspected every single bit of the system.

the gas cap on a properly fitted XJS tank should not be vented (though some people have, I understand, put holes in the cap and done away with some/all of the emissions system. This, in my opinion, is not at all necessary though, as there are many ways to improve the emissions system.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #47

Earlier cars like my '83 had a trapezoidal gas filler door that was simply spring loaded with a little notch protruding so you could grab it to open it. Underneath was a totally sealed cap. There was no locking feature. Some owners – and some dealers – replaced the totally sealed cap with a locking cap, but those don’t seal, fuel vapors go right through the tumbler. Later cars, I’m not sure when, went to a circular filler door with a key latch on it. The cap underneath is still a total seal. All venting from the XJ-S tank is supposed to be through the carbon canister, not a leaky filler cap.



dmaggs I will double check all lines and connections…no vent cap…got it thanks
Kirbert, you are correct I have the trapezoidal gas filler door. My bad…not a locking cap. I think the cap is from the factory…very worn.
I’ll find a no vent cap and try that.



I sniffed out where the gas has pooled in the backseat area. Passenger side rear floor.
Removed the rear seat bench, floor carpet and padding. Totally saturated. Scrubbed with baking soda, vinegar, water. Letting it dry out, then Saturday taking it in for professional interior cleaning.
Can’t tell if still leaking as I would have to remove the tank again. Hoping this cleaning will do the trick.
Then rear view mirror on driver side started moving all by itself and buzzing. Removed the fuse for now. LOL never ends.


(Greg) #50

Hmm, gasoline evaporates rather quickly, that’s odd to find liquid a week later. I suspect there’s still a leak, if so, whoever did tank will do it again on guarantee?

Is passenger side the same as gas cap side?



Yes I think they will honor their work. thought since detail is so cheap I’d try that first.
No gas cap is on other side.
I replaced the gas cap just to be safe also.
I’ll let you know what happens.


(Greg) #52

I was just thinking, if the gas cap inlet wasn’t sealed properly, it could leak on fill up.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #53

Yeah, mine used to do that. I think it was water getting inside the door and shorting out the connector to the switch that operates the mirrors.



I think you are right (again)…the piece of windshield chrome molding popped up this week, came un-glued, and it rained here, so i’ll get that closed also. Under the chrome there is a big mess of old glue. I’ll sand that out. What kind of adhesive would you use?
Thanks Kirbert.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #55

No idea. My solution was to open up the door panel and seal up the connectors themselves.



Update. After having the carpets and mats cleaned…found gas soaking the rear passenger carpet again. I returned it to shop and they took it back under warranty. Hope this time they find and fix.

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Got a call yesterday from the shop, and something is still leaking…NO KIDDING. Pad under tank was saturated, and somehow running to the back seat foot well. They removed the tank for the 3rd time and are trying to find leak. I suspect the tank after repair still has a leak. They are going to smoke the system.
More updates coming.


(Ed Sowell) #58

I had mine smoke tested once. Total waste of time and money. In my case it was the left fitting where the fuel is returned to the tank. I previously had the tank coated with the Renu process and the shop had not adequately masked the threads so the fitting wasn’t seating. I finally tracked it down with dye. Very effective.


(Greg) #59

Maybe too late for this, but my '88 coupe was leaking in a similar fashion, but instead of going into backseat, it went into trunk.

Being 30 years old, I didn’t want to waste time trying to fix a steel tank, so spent the $550 and bought a new tank from SNG. It’s only been a few months, but I think it was worth it.

I really hope they can fix it for you. But know you have options.



Thanks Ed_Sowell and gregma:
I was thinking the same thing, as smoke had been done before on it and nothing showed up…i’ll ask about dye. I wanted to see if they could fix the tank as it has no rust…really looks in good shape…but I’m open to getting a new tank…let’s see what they find.
thanks all


(Ed Sowell) #61

Also, I have a sniffer that I’d be willing to loan. Let me know if you’re interested.

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Shop called and they found a small leak in a hose on tank, but not enough to be soaking carpet on rear floorboard. SO, tried smoke test, no smoke leak, now they are using dye.I haven’t mentioned the new tank possibility yet.
Should know more soon. Breaking news to come…stay tuned.