[Hetzer]

I have a problem with the fuel gauge on my XJS 6.0 V12 coupe. After I have filled up, the fuel gauge shows full tank. But after I've run a couple of minutes the meter has dropped to 3/4 tank. After this the meter seems to work pretty normal down to the red line when the fuel warning light comes on. When I fill up the tank it takes 60 liters. Tank capacity is around 90 liters on the XJS I think.

My mechanic replaced the fuel sender, but to no avail. The mechanic now thinks that the expansion tank is loose so it interferes with the fuel sender and that is why the gauge shows too low. According to him the only way to remedy this is to replace the tank, because you do not get attached to the expansion tank without actually cutting up the gas tank - not a viable solution.

Have any of you heard of anything similar, is a loose expansion tank a likely explanation or could it be something else?

 

[Reg]

Hi Hetzer,

I'm not sure about the later fuel tanks, but mine (1989 convertible) has a seperate small tank under the battery to make sure there is no loss of fuel supply in cornering etc.

The main tank is split into 3 compartments with baffles, again to stop fuel sloshing around I think, when filling up the XJS is know to have a problem with 'swirl' in the filler neck, which keeps cutting the fuel filler gun off, and can sometimes make you think the tank is full when it isn't. This has happened to me a few times. The tank cpacity is around 80 ltr.

Fuel sender units and guages are also know to be a bit temperamental at times...

It may be different with later tanks with inbuilt fuel pumps etc.

I wouldn't go to the trouble and expense of changing the tank for this minor defect...

Cheers

Reg

 

[BigCatXJS]

I too had a problem with my fuel gauge. The fault was eventually traced to excessive use of the loud peddle, especially on fast A-roads :>)