any tips or tricks?

k

Hook up the gauge to a 12V power supply.
Hook up a variable resistor (potentiometer, you can get these at radio shack) to where the sensor would be wired.

Turn on the PS, and turn the knob on the pot until the needle just begins to lift off of empty.
Power off, unhook the Pot, and measure the resistance with a DMM.
Repeat test adjusting until you just reach full on the gauge and remeasure the resistance.

Now you have the "full scale" of what the sensor changes between empty & full.

Or you can use the ohmmeter to measure the resistance directly using the same procedure for empty and full.

have the ohm meter not a variable poten. thanks guys.

k

Not to add confusion to the above, but using the ohm meter, no need for 12+, just put your ground on the sending unit body and the positive lead on the post(or spade, don't recall) on the sending unit & move the float arm to see if your meter moves accordinly. It should.

Keith

I thought he wanted to calibrate the sender so I was giving the info to find out what the gauge expects to see (which is still useful)

First see if it moves. I have had several that where gummed up, and had to be cleaned to bring them back to life. Don't forget to check the low fuel warning light also. The OHM Meeter will do this also, but it will be a open circuit to very little resistance. Or should be very little resistance.

Turn 'em upside down. Does the float move?

Turn 'em rightside up. Does the float move?

Hook an ohmmeter between the ground pin and the gauge sender pin. It should read about 70-80 ohms when the float is at the bottom. Turn the sender upside down, and the resistance should drop to something on the order of 5-15 ohms.

Resistance between ground and the other post (the one for the light) should be infinite with the sender upside down. Turn it rightside up, and the resistance between those two pins should drop to zero when the float touches the bottom of the tube.

--DD

Test like the other said with the ohmmeter and in addition, tilting the sender one way or the other, try to get the float in different positions and make sure the ohm reading is smooth with no open spots.

I had the problem with mine that it had open spots. I had to disassemble and clean the contact wires.

Resurrecting an old thread here, but how do you "un-gum" or clean a fuel sending unit. Had my tank out for a while recently, and after I put it back in, I filled it up, but the gauge only reads half full. It worked fine a couple of years ago, so I am thinking it just needs to be cleaned. Any tips?

Carb cleaner or brake cleaner. And luck. Your odds are probably better if you can soak the part in a bath of the solvent for a while.

The sender tube can be disassembled. I haven't done it, but that's what I have read here. The wires can be cleaned CAREFULLY with something like a scotchbrite pad. (Did I mention to be CAREFUL with them?)

--DD

Bringing the thread back to life.

Do any of you know what pin does what?
Its 4-5 pin on this top (I think)

It does move

I was tempted to remove the super small nut on the bottom to clean things out, but I may just ruin it doing that....so a simple test may inform me what to do next.

Rich

Hopefully this post link helps make sense of the connections and what they do.

http://www.914world.com/bbs2/index.php?s=&...st&p=575364

Brown is ground, green is gauge, black is the warning light IIRC. Correlate the wires from the plug to the sender and you should be able to test it with a meter.

I took one apart very carefully to remove some FOD inside the tube. The wires inside look pretty fragile. Not a complicated task, but a gentle hand is a must.

Take a tall container of lacquer thinner and put sending unit in it. Let it set for awhile. Lift out and drain. Flop from end to end and listen for the float to go in both directions. Should be good to go in most cases. Take the ohm readings.