Jump to content

fuel sending unit


juno2109

Recommended Posts

  • Replies 8
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

One side of the sending unit is a black wire. This black wire must be grounded or go to a good ground.

 

The other wire is a YELLOW wire that joins the truck harness and enters the cab under the pass side seat where it connects to the cab harness. From there it travels up behind the dash to the instrument cluster and is the #9 wire (still YELLOW) on the round plastic plug on the back.

 

 

Now if your gas gauge is simply not working ....

 

1/ Ground the YELLOW wire and it should read FULL. If it does then the problem is either the tank sender or the ground wire.

2/ Does the TEMP gauge work? If both gauges do not work, the problem is likely the small voltage regulator that supplies both and not the gauges at all.

Link to comment
  • 3 years later...

First, the Temp gauge works (a miracle, yes I know)

 

I put 5 gal in mine and the fuel gauge is on E.  That is, it moved up to E.

 

I have done no diagnostics because I am pushing to getting on the road after buying this project 1.5 years ago.

 

What typically fails?

  • Wiring connectors?  this truck had massive failures from wiring corrosion:  alternator, VR, horn contacts, wiper switch to list some.
  • Sending unit itself:
    • float arm pivot freezes?
    • resistor wire breaks and unwinds?
    • resistor wiper arm fails?
    • resistor wire/wiper poor electrical contact?
    • poor sending unit internal electrical connections?
    • ?

Any failure in the sending unit itself, there is a 99% chance I can repair it.  But dropping the tank to get at it is NOT something I want to do.  Maybe shoot some white vinegar on the top of the tank and hope for the best? haha

 

But considering all the corruption done to this truck, who knows what the monkeys did to the wiring itself.

 

 

EDIT:  Is it possible to reach above the tank and touch the sending unit?  Can I wiggle the electrical connections? 

 

(Of course now this is going to be a Grand Mess since I loaded the underneath up with the Chevron Marine Rust Proof Compound L discontinued in the USA but still sold by Michigan Petroleum Technologies.)

Link to comment

External mount near rear wheels collects wet and mud on top of tank. Connections are at risk for corrosion.

 

Next the tank seams can rust and leak. Had this and was able to solder it up. Almost any hole or poor hose can let crap in and rust inside. Had a gummed up (varnish) sender from siting and the gas evaporating. Had a dent that pushed up the sender and the pick up tube so gauge wouldn't go below 1/4 empty but it would run out of gas

Link to comment

First, the Temp gauge works (a miracle, yes I know)

 

I put 5 gal in mine and the fuel gauge is on E.  That is, it moved up to E.

 

 

This would indicate to me that it was stored empty with the sender down at the bottom. When 5 gallons (almost half a tank) was added the sender only moved up slightly. I had a sender like this covered in varnish, basically glued. I cleaned and gently worked it up and down a little at a time to not bend the arm and got it working but it will have to come out.

 

Possibly gash sloshing around may loosen it, maybe....

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.