Fuel tank sender resistance test results

[Philip Wardle]

Just been in the shed testing a selection of fuel tank senders, two used and one NOS in the original cardboard box. If it's af any help to anyone, I measured the resistance between ground and the "T" terminal and found it to be 30 +/- 10 ohms in the full position, and 250 +/- 10 ohms in the empty position. Only the NOS sender appeared to have a reliable switch (which is normallly open) between ground and the "W" terminal. Given the cost of these I if anyone has managed to get one apart to make repairs?

[jbuckl]

Only ever fitted new floats or complete assemblies.

Getting a reasonable reading took a bit of trial and error to be honest, careful tweaking.

[sujitroy]

One I had in a tank of 1/2 full fuel was seized half way up. The car was sitting around for many years. I opened it up and got it working. The resistance of a few I have varies, which was annoying as when the tank is full, the gauge shows less than full. Sujit

[marshman]

One I had in a tank of 1/2 full fuel was seized half way up. The car was sitting around for many years. I opened it up and got it working. The resistance of a few I have varies, which was annoying as when the tank is full, the gauge shows less than full. Sujit

In that case you can "tweak" or calibrate the guage to match the sender, simply adjust the slotted screw accessible through a hole marked "F" on the rear of the guage until it reads full when the tank is full.

Same applies to get it to read empty when the tank is empty, just adjust the other slotted adjuster marke "E"

Be aware that tiny adjustments make a large difference to the needle position.

[sujitroy]

Some time back, I messed around calibrating a few of my gauges to the specs. I have a video here. https://youtu.be/fKRThZiYSbA?si=vTsyp-01ex8RA4U7 It's not that easy. Adjust one, and the other end changes.