I've only had this '86 XJ6 for a few weeks and have been driving it daily, so far without any problems. I've already replaced the cooling/heater and fuel hoses just as a precaution. Other than that I've replaced the front shocks and have carefully looked everything over with the help of my mechanic neighbor who used to work on these back in the UK when they were new. So far it looks like it was very well cared for and maintained by the previous owner.

The fuel gauge appears to be working but isn't registering properly. I've tested the fuel sending units for both tanks by disconnecting the pail green wire and jumping that to a good ground and the gauge goes all the way up to full. So I assume the wiring is good.

I replaced the sending unit for the left tank (the right one was very recently replaced by the previous owner). I assumed that would fix the problem but it didn't, the needle raises just a little to show almost empty even though I just put in over eight gallons. The right tank is full and when switched over to that tank the gauge goes up to maybe 1/4 tank. Before I filled the right tank the gauge showed almost empty so the gauge did go up a little after filling but nowhere close to full.

Am I correct in assuming that means the gauge is bad or could it be something else? Or can the gauge be re-calibrated somehow? I'd hate to replace the gauge if it could be something I'm not thinking of. I'd appreciate some help!

Emil

 

Yes as with most cars you need to bend the arm after vefifying with a multi meter that the arm swings to full and empty correctly reading the ohms

 

Thanks, hadn't thought of bending the arms! Didn't have to do that when I replaced the sending unit in my MG but I guess I was just lucky. Is there somewhere I can get the correct readings for the multi meter? I assume I'd need the readings for full and empty?

 

I dont know maybe someone with come along with them. But back then there were no workshop manuals and half the wiring diagrams were wrong. A lot of the reason jaguar got their rep. back then. Can't fix without good info to dealers. I replaced my nissan one and it was off out of the box so i still need to drop that tank and tweek the arm. Yeah i replaced it 3 years ago so you can tell im enthused

 

LOL. Thanks again, I'll have a look at it this weekend and maybe experiment a little if no one else has an answer.

 

I just happen to have my gas tanks out and wanted to verify that the senders were working before I put them back in. The car wasn't running, no engine and had been sitting for 15 years when I bought it. I connected my DMM (ohm scale) between the ground lug and main connecter on the sender bung and got 19.1ohm empty and 250ohm full. This has very little to do with determining what the gauge will actually read, but I feel confident that my senders are at least working. Hope this can help you.
Dave

 

Both of my tanks read 1/4 full (permanently) when I bought my XJ6. The gauge was fine but both senders were useless. From my experience with old cars the sender is invariably the problem--or the grounding of the sender.

 

Might or might not work

Sender outside the tank. Jump the connections so as to connect the senders to the guage. Read the guage with the floats down. Empty? Great. Manually raise the float. Full ? Great. Not so? Adjsaut by bending judiciously .

Carl

 

Solved it! The new unit tested perfectly before installing it. I drained the tank and put a little over a gallon back in then put the unit in and carefully bent the arm until it was on empty. Put another five gallons in and the gauge stayed at empty! So obviously something's wrong. I removed the unit again and stared at it for a minute then realized the problem. The new unit was for the right side tank, not the left. Looked at the package and it's labeled left. Wrong label!

The float was offset to the wrong side for the left tank so it was getting hung up against the side of the tank. I carefully bent the rod to position the float the opposite direction and put it back in. Turned the key and the gauge went right up to about half a tank. Problem solved!

I won't mention the vendor since everyone makes mistakes but I'll let them know just so they can check their stock before someone else has a problem.

Thanks, everyone, for the suggestions!

 

That's frustrating but glad you solved it. One would think suppliers would be extra vigilant with drivers side/passenger side parts.