1 of 7
Story of our life, tank showing empty, but we know there’s a little left. Time to investigate.
2 of 7
3 of 7
If you have the choice, start a project like this with the tank as empty as you can manage it. Having a fuel gauge that doesn’t work can make this a bit of a chore. A transmission jack makes unbolting the tank exactly 1000-times easier.
4 of 7
Once the tank is out, we pulled our old fuel-sending unit and compared it to the new one we received. Obviously the wrong one was installed at some point, which may or may not have been the editor.
5 of 7
Test your old and new unit using a multi meter set to the ohms scale. Our new one tested out just about perfect with around 73 ohms empty and 10 ohms full when measuring from the fuel sending unit wire to ground.
6 of 7
Our factory 20 gallon unit is showing its age and hangs down lower than a snakes belly in a wagon rut. For the price, one of Omix-Ada’s 15 gallon units are beautifully made in North America and use better plastics then the 1980’s unit we have been beating on for years. We didn’t have time to build a new skid plate and tuck the tank out of harm’s way at this time so we slid the new sending unit in and got the Jeep back on the road.
7 of 7
Words and photos by Bryan Irons
Stinky Jeeps gets more reliable fuel system with Omix Ada.
Of all the old 70’s and 80’s rigs we’ve owned, all have started their new life with us wearing their original wiring. Old wiring is just that… it’s old; most of the time they have been butchered, overloaded, tattered or just plain worn out. In fact, not a single piece of original AMC copper remains in the trail rig my family affectionately dubbed “Stinky Jeep” because of all of the aforementioned issues. OK, the one remaining piece was the fuel level sending unit, and it didn’t work. Go figure.
Most fuel sending units work on the same premise; a float resides in the fuel tank and by action of a slide or a lever, adjusts the resistance of a potentiometer (adjustable resistor) that the fuel gauge reads. Moving parts and sliders mean that they can wear and wear out. Ours wore out to the point of shorting and taking the fuel and temperature gauge with it. AMC’s infinite wisdom decided to power two of the most important gauges from the same source. Some days I’d like to strangle an engineer.
Different manufacturers use different ohm ranges, so do a little research before deciding yours is toast. Our abomination pile of mid 80’s Jeep had a sending unit ohm range of 8 ohms full and 80 ohms empty. These can easily be checked with a simple multi meter to make sure you are getting the correct readings back to the gauge. Remember that to complete the circuit you require a good ground; this is especially true with a plastic fuel tank like ours.
After removing the unit from the fuel tank in hopes of an easy repair, it was realized that a complete new sending unit was required. This was a simple fix, but only because replacement parts are still made by Omix-Ada. So the trigger was pulled for a new sending unit and we replaced the smouldering shrapnel of a gauge with the new Dakota Digital VHX units we featured a few issues ago.
Omix-ada