760 fuel gauge not working .....!

running a 760 gle 1990.
The problem a none working fuel gauge, or intermitent one.
Can anyone suggest a thorough test procedure to pin the fault down?

 

Hi Ian,
The models around 1988 were well known for having this problem. Don't know
if the later ones were the same. The problem was with the fuel gauge. I had
an 88 for many years and for about 5 years of it's life ran with the fuel
gauge not working. I just filled the tank as and when necessary and noted
the mileage with the trip mileometer. I tried many different ways to get the
gauge working. To eliminate the in tank sender, the haynes manual gives a
description and a value of resistors to put in series with the wiring of the
fuel gauge circuit. ie. in place of the in tank fuel sensor. With thge
resistors in circuit the gauge records 3 quarters full. I bought a fresh
gauge for the car (difficult to get hold of except from main dealer and
pricey) but that didn't cure it. The gauge connects with three pins at the
back into the printed circuit. I think this is where the problem lies and
that the answer is to tighten the connections between the pins and the pc
board. I was going to try this but finally sold the car and bought an 850. -
Roy

 

hi roy
cheers for that ill give it a whirl.
The new girlfriend was messing up my odometer method so I didnt know where I
was.Ill let you know how I got On
cheers Ian

 

Well, I've heard of various methods but the 'odometer method' is a new one
on me! This new girlfriend seems interesting, at least she will be when she
get the hang of it!- Roy

 

Had similar prob's with my 84 760 T, never fixed it. ( I know, BIG
help)

But recently, I aquired an 89 780T, when I purchased it I noted to the
seller (among many other items) the gage did not work.

Whereupon he gave the dash a short slap with his hand, right above the
left side of the dash. Instantly, the gas guage sprang to life.


He said, "Oh yeah, common with this vintage".

I now do this every time I get into the carand start her up, and it
always does the trick for mine.

So obviously, there is a connection issue in mine at the dash panel
itself.

It will be an easy fix when I finally get the motivation to take it
apart, maybe a scrub with contact cleaner/copper brush or whatever.

So look at that area, try giving the dash a little spank, see if that
helps.

It's free, and may point you in the right direction quickly if it
causes the guage to start working again.

 

Think this proves the point about the three pronged connection on the back
of the fuel gauge itself into the printed circuit.The only problem is that
the connection itself is too small to clean with anything other than very
fine sandpaper but I expect this would tend to loosed the connection by
making the prongs thinner. Also, when i took mine out the prongs were clean.
Cotact cleaner wouldn't harm but I suspect a little surreptitious bending of
the prons (not a lot) would tend to tighten the connection. - Roy

 

My experience with connectors is that the problem is often that the female
side spreads out and makes poor connection. I don't know what style this is,
but I've had good luck with several types sliding a needle between each
female contact leaf and the connector body. It isn't a permanent fix, but
sometimes it is lasting enough.

A chemical called "Tweak" sold at audio shops is the best contact enhancer I
know. It is a diluted version of the shockingly expensive Stabilant 22a.

Mike

 

The connectors on the gauge are basically just 3 pins on the gauge which fit
into 3 holes on the printed circuit. Nothing more sophisticated than that.
You can't even use solder to provide a permanent fix as the printed circuit
is made of plastic. - Roy