Hi, 2002 XJ8, 80k miles. Mylow fuel light does not appear to be working correctly(and never has). Liight comes on when you turn the ignition switch to on and then goes out qhen you start the engine, but with the gauge down into the red and display saying 30 miles or less to drive it never has come on. Does anyone know what level of fuel should turn it on? And any ideas of a cause? thanks, Keith

 

The plastic arm guide is known to wear, I need to replace mine, it never reads completely full.

 

When your DTE shows 30-ish miles and you fill it, how much fuel are you putting in to fill it? Wondering if your gauge is reading right and maybe you're never getting below a quarter tank.

 

The problem with a 2002MY tank is that everything is INSIDE so no easy access to the level sensor from the back of the tank for diagnosis.

 

From memory it should come on with 2 gallon left, so about 30miles range.

 

Just a warning: repeatedly running the tank to near-dry is courting fuel pump failure!

 

You may be on to something. I will have to watch how much it holds in relation to gauge reading closely. Is the capacity just over 23 gallons(us)?

 

The TOTAL fuel capacity (volume of the tank) is somewhere near 23 US gallons BUT.............

The total USABLE fuel capacity is closer to 20 US gallons.

 

20 gallons. Interestingly enough in the 2 years and 45,000 miles I've put on my car, I've don't think I've ever hit 18 gallons at the pump and I regularly run it down to the low fuel light.

The trip computer will also tell you how many gallons it think you've used since you last reset the computer. Reset it the next time you fill it and see if its close. Mine is usually at least a gallon higher than actual.

 

I think that only once in four years of ownership of an '03 have I ever put 20 gallons in the tank, and I was really sweating getting to a pump. My light comes on at about 18 gallons at the beginning of the red area and I generally refill it at that point, if not just a tad sooner. This 18-gallon red light business has had me thinking I actually have a Euro-spec tank (same part number best I can tell). My vehicle is right at 1000 from the end of production and I'm guessing that at this point they were throwing any bit of dwindling stock parts at the remaining cars.

 

Your US gallons are smaller than proper UK gallons, so that'll be why the same part number tank has two capacities.

I forget the exact reason but gallons of oil/beer/water etc all used to vary & you lot standardised on a different one to us as I recall.

 

The US inherited the use of its current measuring system from you chaps in the UK.
So the use of the word "proper" seems a bit too far reaching. While the UK eventually
fell in line with the rest of the sentient world, the US has resisted the change primarily
for economic reasons. Someday.....that might change.

 

You standardised on the 'wrong' gallon, hence it's not the proper one

Personally I try to still use proper measurements as I don't like the french so won't use theirs if I can avoid it. Oddly enough someone suggested metric measuring in the UK long before france adopted it, but we said that's a silly idea & rejected it.

 

Well Hooli, I suspect perspective changes depending on where you stand.
The main thing is to respect the "proper" position of the other.