I just purchased a 2003 XJ8. It is literally in mint condition the the exception of a small issue. I drove it about 250 miles to home from where I purchased it, and today the fuel gauge began acting weird. I filled it up, no issues. After about 20 min. it dropped to empty, although I know it has at least 2/3s of a tank. Now it is showing correct level at start up and then goes back to empty. It has done this several times,
Any ideas here?
The service records show new fuel pump installed late last year, and the car is running perfectly.
Many thanks!

 

Sounds like a failing fuel level indicator in the tank.

 

What's the fix? Can it be easily replaced?

 

I believe the 2001 and later models its on the carriage from the top of the tank. Thus having to pull the tank back like replacing the fuel pumps (lots of threads on those to review).

Found this thread...https://www.jaguarforums.com/forum/x...roblem-131069/

 

I just purchased a 2003 XJ8. Mint condition, runs like a champ. One issue. The fuel gauge is acting up. I have been reading several threads all with different approaches as to what the problem could be.
That being said....I also own a 1998 XJ8. Eveyhing on it works with the exception that it has a bent rod, so engine is shot.
Is it possible to just switch the fuel tanks out on these cars? 98 tank into 03 car?

Prior to doing anything I am going to unhook the negative battery cable for a minute to see it that resets anything.

 

Thank you. One thread I found suggested that removing the negative battery cable for a minute MAY reset the gauge and/or the sensor. I'll try that in the morning. Also, I have a '98 XJ8, do you know... would that fuel tank fit my '03?

 

+1 on all of Highhorse's excellent replies.

I just took a glance at the parts numbers and diagrams, and in addition to the relocation of the fuel level sender, it appears there is some difference in the evaporative flanges between the pre- and post-2001 cars, and probably in the wiring harness for the fuel pump and sender. That doesn't mean you couldn't swap tanks with some work, but why bother? It would only be half the job to pull the tank in your '03 far enough to remove the evaporative flange so you can replace the fuel level sender. But first, it would be worth checking to see if you can access the electrical connector for the sender to check it for looseness, arcing or corrosion. You might be able to just clean it without removing the tank, but more than likely the sender itself is failing.

Cheers,

Don

 

That does make sense. Especially if I don't need to actually remove the entire tank, disconnect fuel line, etc. I will lower the access panel,and take a look at what I can get to and thank you so much!

 

...I wouldn't have to disconnect the fuel line to move the tank far enough for acces, would I?

 

Probably should had kept this with your other thread so anyone who responded there may be able to answer and keep the subject together for others who may read it later. But, like any other car manufacturer, they love changing little things so they don't fit in other model years (better redesign usually). In this case the 98 sending unit comes in on the middle of the back of the tank and would have to be removed and plugged. Then I believe the cover cap is larger to accommodate the carriage with more items on it. I am unsure if the carriage sits the same in either tank, thus the good possibility of incorrect fuel level readings and if the fuel pump isn't sitting flush, you'll get a slosh stutter when fuel is low in the tank.
Why not just check that connection like Don recommended, ..so much easier. If you do find its bad, you can check with a used unit here... Car-Part.com--Used Auto Parts Market ... if you choose to go that route...those units aren't exactly cheap. If the car is a needed daily driver, I'd find a replacement sending unit (new or used), get it ordered, fill the tank and reset your trip meter and not go over 250 miles before refilling until replacement arrives. But, I would also run the tank down as much as possible when it comes time to change the unit so it will be lighter to pull out and put back in and less to splash.
All in all, you may just have a bad/corroded connector, that would solve this whole dilemma much easier...

 

Yeah, it was late and I started a new thread, not thinking. Should have stayed with the original thread. Okay, thank you for the great advise. I will check connections as suggested and go from there.

 

It may be possible to carefully pull the tank far enough to remove the evaporative flange without disconnecting the fuel lines, but since it is very easy to damage the lines, the safest route is to disconnect them.

Some owners have cut through the sheet metal in the rear parcel shelf to access the flange/fuel pump without removing the tank (I know this can be done on an X300 but can't remember for certain if there is any reason it can't be done on an X308).

Cheers,

Don

 

I saw something to that effect. Okay, thanks again Don, you've been very helpful.

 

LAST THING, PROMISE lol...
I saw a connector that I could get to and pop out, possibly clean the connection with some electrical spray cleaner. It is white and at the front/right of the flange, do you know if that is the one for the sender?
I do know enough to unhook the negative cable before doing anything of that nature....
Thanks again Don!

 

The fuel pump and sender connect through the same electrical connector, so that is probably the one you are looking for. One fuel pump wire is Black and the other is Brown with a Green tracer line. The two fuel level sender wires are Red/White and Black/White.

Cheers,

Don

 

Excellent! Thanks again Don
Cheers!

 

I merged your two threads. Problem solved.

Cheers,

Don

 

Great! Nice job Don, you are very helpful!

 

It's the fuel sender unit. You do NOT have to cut the car's panels to fix this, I find that 'fix' bonkers.

Anyway to change the unit undo the fuel filter line to the tank, release a couple of chassis clips on the other fuel line. Check the lines going up into the tank have the protective plastic shields, about 3-4" long....

Undo the 2 sliding locks that hold the tank to the chassis, tie up out the way, bootlaces suffice.

Unclip the electronics, filler tube and breather and pull the tank from the top to rotate so you can access the top. Mallet and driver the lid off and swap the part. Helps to have a low fuel level, but stay local

Reverse to install and go for a beer.

 

I also saw a video that the guy didn't even release the fuel lines, just pulled the tank out enough to get to the top.