82 GL Hatchback Fuel Sending Unit, What and Wherefores?

[Jamster]

Howdy Folks,

Background details: I have an 82 1.8 L, Hatchback AWD in great
condition, no rust and with center constellation headlight.   Love this
thing.

 

Problem:

My fuel gauge has been going all over the place for the last two
years; floating high, low and empty.  Originally, I added some solvent
to the gas and that worked for about a year, ( I presumed by cleaning
off the varnish on the sending unit).   But recently the gauge isn't
working except for the occasional magical floating needle effect.   So
this weekend I took out the fuel sending unit from the rear of the gas
tank.   I cleaned it up and checked the resistance on it.  There was
only a minute reading difference in the high and low section.  Not
nearly to the specs written in the book.     I cleaned it up with
acetone, and although I have good continuity I can't get it to read on
the fuel gauge at all anymore.  

 

My power to the Fuel Sending Unit reads 7.2 volts D.C. with the ignition on.     

 

I'm looking for suggestions on getting a new/used sending unit, or
making one.  The difficulties I've had is that I can't find anything
that fits in horizontally like the original.    Supposedly on ebay there
is a sending unit that would fit, but it doesn't look anything like the
original.   Suggestion on finding parts.

 

I'm a newbie to this forum, so I apologize if this has been answered before, I've had difficulties navigating this forum. 

 

In the back of my mind, I keep thinking that the dash gauge is what's
bad, but that doesn't make sense to me because after "Fixing" cleaning
the old one I'm not getting any reading.

 

Thanks

Jamster

[Gloyale]

you could check the gauge working uising a few resitors.  

 

look at the specs for half full and full resistance, and get a few close resitors and put them in place of the sender and see what the needle reads.

[naru]

I am confused.

Does the sender have proper resistance now?

Acetone likely won`t do much.

 

I use a pencil eraser and a gentle touch to clean the contact areas.

Has not failed yet.

[Jamster]

Update:

 

I realized that the ground to the sending unit from the fuel gauge was okay, but that sending unit's itself wasn't grounding properly.  Previously, I had tested it for continuity but it must have had a hairline break in it.     I just used the exterior mounting face plate's bolt as the new ground.    Sure enough the fuel gauge went to full (full tank at this point).    I have to do some driving today, so I should be able to tell if it is working completely.

 

Many thanks.