How to test / replace your fuel tank sending Unit

Thursday Tech Specs...

Problems with your fuel gauge... ? Think it's stuck?
Does it read full or empty all the time?

Here's what your problem could be... Test it, Fix it or replace it!

My fuel gauge only reads full: 

If you can't make your gauge read anything but full then depending on your ohm range you may have one of the following problems:

The sender may not have a proper ground or there is a break in the sender lead wire or it isn't connected at all. Most common when you have a 0-30, 0-90 or 10-180 Ohm sender unit.

Most likely your sender lead wire is grounding out somewhere. Or possibly the center terminal on the sending unit itself is grounding out against the body of the car.

Most common when you have 240-33 or 73-10 Ohm sender unit.

My fuel gauge only reads empty: 

If you can't make your gauge read anything but empty then depending on your ohm range you may have one of the following problems:

If you have a 0-30, 0-90, and 10-180 Ohm sender then most likely your sender lead wire is grounding out somewhere.  Or possibly the center terminal on the sending unit itself is grounding out against the body of the car.

If you have a 240-33 or 73-10 Ohm sender then the sender may not have a proper ground or there is a break in the sender lead wire.

Here are some really helpfull video's about how to check and replace your ( stuck ) fuel gauge / tank sending unit...

Check from: 1.14 min



How to find sending unit Ohm range


How To Install A Gas Tank Sending Unit

Will almost be the same at all vehicles...
Chevrolet, GM, Pontiac, Buick, Oldsmobile, Cadillac, Coupe's, Sedan's, Trucks... whatever

Which sender should I get / use: 

The resistance of your fuel sender has to match your gauge. 

For instance the resistance of the stock gauge in a 1955 Chevrolet has a value of zero ohms when empty and 30 ohms when full. 

Here's a list for stock gauges:

Ford Gauges up to 1986: 73-10 Ohms

Ford Gauges 1987 & up: 16-158 Ohms

GM Gauges up to 1964: 0-30 Ohms

GM Gauges 1965-1997: 0-90 Ohms

GM Gauges 1998 & up: 40-250 Ohms

Mopar Gauges up to 1986: 73-10 Ohms

AMC Gauges 1950-1977: 73-10 Ohms

Here's a list for some popular aftermarket brands / gauges:

Autometer Gauges: 240-33 Ohms: Most common 

( however other ohm ranges are made ).

Classic Instrument Gauges: 240-33 Ohms

(excl vehicle specific gauge kits which use factory ohm range)

Dolphin Gauges: 0-90 Ohms

VDO Gauges: 10-180 Ohms

Dakota Digital Gauges: Programmable to work with most Ohm range senders