Hi all,

I just inherited a very nice 1992 XJS V12 Convertible from my dad, and it has the common fuel vapor smell (with windows cracked or down) along with the pressurized whoosh when you release the filler cap. This afternoon I dug into the trunk, expecting to find a gravity fed surge tank in the lower right, along with a host of fuel supply and vapor lines. What I found was a fuel tank that looks a bit more modern - it doesn't have the gravity feed pipe on the lower center part of the tank, instead it has what looks like an in tank fuel pump. I couldn't really make out any vapor lines. The tank has 1998 date code on the sticker.

Any advice on where to start? I was expecting a bunch of hoses that supply fuel and relieve tank pressures, ultimately ending up in the drivers front fender at the charcoal canister/Rochester valve setup. Here are some pics of the tank, including a close up of the part sticker.

 

Hello

Just new to the XJS ownership world and my fuel tank is a bit rusty on the outside (as seen through the back seat portals. The following link shows the part number and lay out

https://www.jaguarclassicparts.com/uk/part/NHF5908GA

Cheers

 

Hi Bez

I've just fitted a New In-Tank Fuel Pump to my 1995 4.0L XJS which has the same Tank Setup as yours and the Breather Pipe you could be looking for, is on the Neck of the Fuel Filler, in a really awkward place to get to

Where it comes off the Neck of the Fuel Filler Pipe and then goes through a hole in the Floor of the Boot/Trunk to vent off outside and this very awkward to get to Pipe, can get blocked with Crud, or even rust right through

So that metal pipe could be the the cause of your problem

 

A better view. And yes the tank has been replaced.

https://www.jaguarclassicparts.com/u...up-to-v-188104

 

Thanks for clarifying...it seemed obvious that the tank was replaced, but it helps to get confirmation. My question is, in the diagram from malc4d's link, the evaporative loss flange (#3) shows two nipples, but mine only has one. Based on the description, it seems like that whole part of the fuel system is what vents the tank. Looking at my picture, the two metal pipes running along the top edge of the tank function to capture overfilling (upper larger of the two that ties into filler neck) and the smaller, lower pipe turns down at the edge of the tank where a rubber vent hose runs down the side of the tank and then connects to another metal pipe which I assume then leads to the rest of the fuel evap system. Is the rest of the system located in the same location as older models (in the driver side front fender)?

Also, where the heck are the fuel supply and return lines in this system? Are they underneath the tank? In the diagram I see the two hoses that I assume are submerged and feed/return the in tank pump, but where do they go on the other ends?

 

Hi petebee

The following Photo may answer your Question, as the Fuel Pipes connect from under the Car and you can also see that rusty pipe that comes off where the Pipe splits into two from the evaporator

I was taking the Tank out anyway, so it was very easy for me to renew it, as I made up a New Pipe myself but you may have to remove the Tank if you want to do the same, unless you get very lucky and are able to jiggle that pipe out

Other than that you could consider re-routing that pipe to somewhere that is easier to get to but as for Taking the Tank out, that is a Total PIA which you might want to avoid at all possible costs

Where also you need to consider, that it may not even be that pipe that is causing the Fuel Smell problem, it could be something else like a blockage in the Fuel cap vent somewhere along the line



Fuel Pipes and evaporator drain pipe

Though if you ever really feel the need to Take the Tank out (which is a job I never ever want to do again) to clean it or change out the Fuel Pump

You can see how I did this on Page 92 of my 'Cherry Blossom' restoration thread and here is the link to that page

Removing the Fuel Tank on 'Carmen' my 1995 4.0L XJS to Clean the Tank and Replace the In-Tank Fuel Pump

 

Thank you for the image OB and the link to the adventures of removing and installing the fuel tank! I squeezed up under the car in front of the right rear tire to get a good look (my goodness these cars are low!). The hoses attaching to the pipe outlets on the tank look good without any seeping or leaks. I did notice that the fuel filter was changed about 7K miles ago, and it is a Jaguar filter. I was also able to see where the vent pipe/hose comes out underneath and then goes forward to the front of the car...assuming it lands somewhere up front. Does it make sense to disconnect the lines at the front and the rear, then blow compressed air to determine if anything is blocked? That would help to rule out any blockage in the system from the tank to the fuel evap stuff that I imagine is tucked up under the driver side fender (hoses, pressure valve, maybe some vacuum lines), and allow me to narrow down the cause of the tank pressurizing and not venting properly.

 

The evap stuff is in the drivers front fender well, if you search under my name I did a long write up on how to test and replace the components up there. Basically after accessing the compartment behind the inner fender cover it's a matter of testing vacuum, checking hoses and seeing if the lines and or canister are full of fuel and not operating correctly. There is another electrical operated valve under the drivers side relay box that can fail as well, it's also simple to test once you have the fender open. Basically the US evap system is real POS and seems cobbled together with various Delco and other parts.

 

Thank you...that looks quite easy and I found the new Delco valve is available on Amazon. Think I'll just go ahead and spend the $30+ on new valve and some fuel hose instead of testing the old Rochester valve.

 

Hi Petebee

The Inlets and the Outlets on the Fuel Tank are Self Sealing, so not much point in taking those Fuel Pipes off, unless you want to blow them through, if for instance you just fitted a New Fuel Pump

Disconnecting and Re-Connecting those Fuel Pipes from the Tank, isn't quite as easy as it looks, as those Fuel Pipes are only just long enough for them to reach the Tank

And unless you can make one you need a Special Tool to get them out or push them back in, though if you decide to do that then whatever you do DO NOT LOSE THOSE CLIPS! as one of those is NLA

 

Wanted to post a follow up as I believe the fuel vapor issue has been resolved.

I suspected the Rochester valve was not functioning as others pointed towards, so I purchased a new one and proceeded on the install - in my case removing front driver wheel and taking the plastic inner fender cover on the forward side of the driver wheel well. When I removed the tank side hose on the existing Rochester valve I tried to blow on it (back towards tank)...the line was plugged. So I once again removed the trunk carpets, battery and fuel tank cover to expose the vent lines in the trunk. I had to remove the black tank brace at the left bottom side of the tank to access the hard line that travels towards the front of the car. I blew on the rubber hose that connects to the tank pipe and the vapor plumbing on the top of the tank and encountered no resistance. So we attached a small piece of hose to the hard line, sprayed a bit of brake cleaner and blew out a nice amount of brown fuel sludge. With the line unblocked air flowed freely to the front of the car. So I put my new Rochester valve in, attached the fuel/canister hoses and the vacuum line and buttoned it back up. Drove for about 30 minutes with windows down and no more fuel smell! BTW it seemed like the inner cover on the fender had never been removed (screws were sprayed with factory undercoat), so I imagine the valve was original. Since the tank has been replaced, I am guessing they never bothered to check if the tank was venting properly in the first place, and just replaced it without even correcting the actual problem!

 

it seems that almost any car that has the tank and fittings mounted inside the car will have some fuel odor!
probably why most tanks are mounted outside the body shell!
ron