I have a 2004 XJR with erratic fuel readings. The sensor(s) do not work correctly when the tank is filled. After 50 miles the sensor(s) begins to work again, but I am concerned about accuracy. Prior owners have had the same problem and had them repaired. I believe that the sensor operation can be confirmed in the vehicle. that is to confirm which sensor is in error. Also, I believe these sensors can be replaced from under the rear seat rather than dropping the fuel tank from below. Any information to confirm would be very helpful

RyeJag

 

There was a recall on this on the My04 models (but only if the customer mentioned it)
The simple answer is one of the 2 senders is faulty

I have attached the TSB but best thing is to just replace both senders
Given one will be faulty the other wont be far behind

Cheers
34by151

 

34by151
thanks for your helpful reply. It does appear as if one of the sensors is faulty. Repair procedure suggests draining fuel tank for repair. Not sure why that would be required if the tank opening was temporarily covered during sensor repair. Any thoughts? I could do the repair outside, so no fumes would enter my home.

RyeJag

 

Just relieve the Tank pressure
Sensors are under the rear seat, just remove the rubber bungs to gain access
Follow the JTIS procedure for best results

Cheers
34by151

 

34by151
Repair procedure mentions tool 310.072A, which looks like an oil filter cap wrench. It appears as if the retaining ring could be removed with a large spanner wrench or other device. Diameter is 6 inches. Did you purchase a special tool or improvise? I plan to order both sensors to be sure that I don't have to go back and repair the other right after fixing the defective one

RyeJag

 

You can normally get it off by hand but if you have trouble make a tool

Just make a tube spanner from some thin wall tube
Shape up dome metal or wood to replicate the fitting
Heat the tube, insert the blank and bash away till you then have yourself a tool!!!

Cheers
34by151

 

34by151
wow, I never thought of making a customer spanner wrench that way! Thanks for your support, off to order the sensors today.

RyeJag

 

34by151
well I put the sensor in on the right side. No error when refueling which I used to get and the gauge level pins low and I would get a low fuel warning light. But I do get erratic readings at times. I suspect the gauge is not lined up properly with the fuel tank. Any guidance on that? I reinstalled per directions, but I suspect I may need to turn the fuel pump, gauge assembly a bit.

RyeJag

 

If you installed it incorrectly you will see an alignment issue on the sender but I suspect you would not be able to install the locking ring with it misaligned

In any case check it right away as you may have a fuel leak

From what you wrote it sounds like the new sender is ok and you have a fault with the other one which is consistent with your original fault

start by performing the diagnostic in the tsb but if it was me i would have replaced both sensors the first time. The reason being if the first one has failed the second wont be far behind

Cheers
34by151

 

34by151
well, you are correct, I should have replaced both sensors and actually did purchase both. The issue is that I did not have the tool to remove the fuel line on the left side, so left that part of the project for another day. There is freedom to rotate the entire sensor/fuel pump assembly while still be able to tighten down on the gasket, thus my concern about alignment.

Do you know if RAW1 is the right or left sensor? I could gather some additional information that way. Perhaps the new right sensor is binding with something on that side

RyeJag