I have a '88 Vanden Plas (series III) and the fuel gauge doesn't read properly (both tanks). I have taken one of the sending units out and manually raised the float to see if it would read full. No luck. I attached a new sending unit and did the same thing...no luck.

Is there something else in the loop I should be checking or is it just a faulty/worn gauge??

Any ideas???

Thanks

Bo...

 

if all other gauges read correctly, it could be the gauge or corroded wires at the back of the gauge.

in my experience, if the car sits for a while, this will happen but tends to correct itself the more the car is driven.

 

My next step is to take gauge out and check. I have owned this car for about 6 years and the problem has been there most of that time (i'm finally getting around to it lol!!!!). I ordered a new sending unit (2 years ago) and finally went to put it in yesterday and found out they sent the wrong one!??!!?

My service manual is unclear...is there anything else in that loop (sending unit to gauge) that could be causing the problem, other than a bad connection??

Thanks!!

 

I think the tank level sensor wires goes to the fuel gauge through the tank select switch. Check the contacts in there, behind the switch.

 

Are you talking about the switch on the dash or the actual control valve in the trunk??

Thanks!!

 

I'm talking about the switch on the dash. This switch selects which tank level sensor to connect to the fuel gauge.

 

yes, the dash switch, but if the tanks are being switched ok, then the switch can be eliminated as the cause. Other parts in rhe loop are the changeover valves, 3 of them, and the fuel pump.

I think it is the gauge. Jaguar always suggests substitution of suspect parts. I would try another gauge. Get a good used one from David at www.everydayxj.com

 

The switch has 2 sets of contacts, 3 wires each. One side might be working correctly while the other one isn't. One set is to supply current to one of the fuel pumps, another set is to select one of the tank level sensors. If you have an indicator light, connect one end to the ground and with the other end touch each of the 6 wires at the back of the switch. You can actually disconnect the switch and use only the plug side. One wire is leading to the fuel gauge and when you ground it the gauge should show full tank. If the needle still doesn't move, either the gauge is defective or the wiring from the switch to the gauge is defective. If you have the manual with electrical schematics, then the wire color will tell you exactly which wire is which.

 

Found the schematics, looks like LGO (Light green with Orange stripe?) wire goes to the fuel gauge.

 

not sure if we are talking about the same car, the Series 3 only has 1 fuel pump.

 

Jose, you're right, my bad, mixed with my series II. Tank select switch instead of switching power to the fuel pumps like on Series II, on Series III activates fuel solenoid valves. In my defense, fuel level sensor wiring is the same

 

mckarlas, not to worry, it can get pretty confusing here! Also are we talking about a V12 ? and are we talking about a USA car? The reason I ask is because the 6 cylinder Series 3 is no longer built after 1987. From 1988 to 1992 the only Series 3 built was the V12 and it was not sold in the USA because it did not meet emissions. There are many in the USA that came from Canada.

 

It is a V12 and is in /was from Canada.

 

Oh and one more question...I see people talking about "resetting" small gauge cluster, due to failed battery. This car has sat for the last 2-3 years without being started on a regular basis. The battery was fried and I had to replace it. Could this have something to do with the problem???

 

you're confirming what I said initially. The car has been sitting. so there is nothing wrong with the gauge or senders, just lack of exercise. Start driving it, keep the tanks as full as possible and you wil see how the gauge starts to correct itself. Batteries die and these cars like lots of electric juice. Keep the battery fully charged. Are you asking about resetting the Oxygen Sensor counter? Easy to do. The counter is in the trunk behind the rear seat.

 

Really?!?! Just drive it?? lol

Maybe I will wait to take the dash /console apart.

Thanks for the input.

 

yes, go on a long drive. 3 hours each way. Burn all the gasoline, refill, repeat. Remove the Floats / Sender assemblies, lubricate moving arm pivots with 3-in-1 oil or sewing machine oil. I have two Twin Tank Jags and they both do the same when they sit.

No need to dismantle the dash to get to any gauge. They are easily removed.

 

Sorry I was referring to the console, to get the tank switch out and check connections. ;-)

 

got it,

to get to the switch, remove the TEMP and MODE knobs, remove the notched nuts, pull the radio panel carefully or the radio first, depending the type of radio you have, then remove the two screws at the bottom of the switches Panel, then pull the panel down as you pull it out.

you might have to pull the Trip Computer too if the wires are too short. Just pry it out from the corners with a thin knife.

A total pita of a job.

Again, if you can switch tanks without any problem, the switch is fine.

 

You seem to be quite the expert on this model!!!! Perhaps you could help me with another issue?? The radio hasn't worked since I bought the car (6'ish years ago). Because it lost power the "high tech security system" (lol) kicked in and disabled the radio. I have read the manual and have the code card. After many attempts I have had no luck. Ideas??