Hello everyone, I'm new to this site, I have a 1988 Hess Eisenhart convertible.
I'm having trouble with the fuel gauge, I recently removed both fuel sensors from the tanks and after I reinstall them the fuel gauge reads full all the time I've ran through several tanks of gas but it still reads full. I also disconnected the battery for more than 24 hours still the gauge reads full. I'm hoping that someone can give me some direction on how I could get the fuel gauge to work properly again?

 

Welcome to the Forums.

If you have the battery disconnected and it reads full it sounds a lot like the gauge has failed or stuck. Did you disconnect the battery while working on the sensors? just wondering if the gauge might have spent a lot of time pegged over maybe?

Try giving it a few old school taps. One of my cars will only read 1/4 full no matter once unless I give it a few taps and then all is good for the rest of the trip.

 

I have a feeling that they are earthing on something. If there were 2 wires (i think there is from memory) you may have re attached them around the wrong way. or if it is one wire, did you put the rubber seal back in?? it may earth out if the seal is not there. One of gurus will swing round soon and give a clearer answer than me.

 

We need to see some pics of your car!!!!!
It's the Law, especially with a rarity like yours.
Is it an XJ6 or an XJS?

 

I may have not explained it so well but the fuel gauge does operate when you turn the key on it goes from empty to full I will check the insulators around the sensor if I remember correctly I don't think it can be wired backwards because one eyelid is larger than the other, my car is an XJS V12 I will try to send a picture shortly

 

OK, I thought you were saying it read full with the battery disconnected. As Richard says it sounds like you have a full earth sensor lead , sounds like something is going on with the recently replaced sensors. Are they keyed to prevent them being installed upside down?

Posting over in the XJS specific forum may get some more model specific knowledgeable eyeballs on your issue.

 

Ok thank you, I will post over on the XJS forum.

 

Here's the picture of my 1988 H-E XJS

 

Now, that is niiiiiccce!!

 

If the fuel gauge issue gets to much for you I can take it off your hands, no problem.

Very nice looking thing.

 

Thanks guys, but I think I'll hang onto her for a little while longer.

 

Sure is nice. I used to see a gent with a similar car at market from time to time. I wonder....


Most fuel gauges rely on floats on swing arms. In turn, those wipe a rheostat to vary volts as a signal to the guage. So, the issue
might be mechanical or electro/mechanical in the tank. Float stuck
in the "up" position. or failed windings on the rheostat.


Inspection needed to diagnose. Lower the fuel level, way down. remove the sender.


Might even use a pair of jumpers to simulate float action and see the results on the guage.


Carl

 

Thank for the advice, I don't think it's my car that you have seen at market, I've never been to the West Coast.

 

Ok, what how I have figured out so far is that if I hold the lower tank rheostat in my hand with the electrical wires connected to it, the fuel gauge works properly but if I install the rheostat back on top of the fuel level float that is installed in the tank then the fuel gauge will go all way up to full. I then removed the electrical wires from the fuel pump thinking that there might be a short, still no change in my results.