Fuel Sending Unit better than others??

[WOLFMANmike]

ok so here is a question who makes the best fuel sending unit for the stock tank? im asking because i bought one from Ebay a few years back but it has never read true so here is what it does if i fill up the tank will read half full then as a drive to say a city away it will read full. however once it starts reading full it then starts to drop quite a bit more than what is really in the tank. for instance last time it read on E i only had to put in 8Gallons before it was topped off. so i know the tank is way bigger than 8 Gallons so is there a brand i should be shopping for that will be better for me that will not be 1 extreme to the other?

[Railroader]

You may have already checked, but just asking. Is the sending unit Ohm rating same as your gauge? You using stock gauge? I believe stock gauge is 0-30, 0 being empty. New gauges are mostly 0-90. Again 0 being empty.

[WOLFMANmike]

Originally Posted by Railroader

You may have already checked, but just asking. Is the sending unit Ohm rating same as your gauge? You using stock gauge? I believe stock gauge is 0-30, 0 being empty. New gauges are mostly 0-90. Again 0 being empty.

No prob. But I did buy a 30 ohm sending unit

[PGSigns]

Is the ground wire from the sender to the cab still there? If you were a premium member you could post in the parts section for a good factory sender. I ma sure there is someone here with one.
Jimmy

[demian5]

I bought a brand new one from truck and car shop, and it sank. Float filled with gas. Had to take it off and have my plumber friend re solder it.

[61K10]

I bought a cheap $29 one and it was Off. full tank and it registered 3/4. fixed my old org one, works fine. I have seen some at $49, don't know if their all the same though.

[Railroader]

The sending units are easily checked, if you have it pulled from tank, with a multimeter. Place positive lead on unit where the wire to gauge goes, negative lead on grounding wire. It should read 0-2 ohms with the float at empty position and 30-32 at full position. If you get readings like this, the problem is not the sending unit.

[demian5]

Originally Posted by Railroader

The sending units are easily checked, if you have it pulled from tank, with a multimeter. Place positive lead on unit where the wire to gauge goes, negative lead on grounding wire. It should read 0-2 ohms with the float at empty position and 30-32 at full position. If you get readings like this, the problem is not the sending unit.

Unless it comes out looking like it was soaked in a metal eating acid for 50 years...

[WOLFMANmike]

Originally Posted by Railroader

The sending units are easily checked, if you have it pulled from tank, with a multimeter. Place positive lead on unit where the wire to gauge goes, negative lead on grounding wire. It should read 0-2 ohms with the float at empty position and 30-32 at full position. If you get readings like this, the problem is not the sending unit.

Can this technique you speak of also be used as a way of setting the unit so that it reads properly from empty to full in the tank?

[bloo]

Yes.

You can do a lot more if the tank is out. It has to be able to go down to zero (or extremely close) and up to 30. If the float hits bottom before the sender gets to zero, the gauge won't ever get to empty. If it hits the top before it gets to 30 the gauge will never get to full.

If the arm is too long, you will never get full gauge sweep because it will hit either the top or bottom of the tank. If it is too short, you will either be able to burn a bunch of gas before the gauge moves off of full (fairly common on 60s vehicles in general), or it will do what you are seeing, and your gauge will get to E too early (you have a gigantic reserve).

The bend of the arm also matters, as well as the length. The float should never hit the top or the bottom, as banging around might damage it. The gauge should get to E (0 ohms) before you run out of gas, and the bend of the arm sets that.

I turn the tank upside down and make sure it gets to 30 ohms or more. Then I turn it right side up and make sure it gets to zero. Then I put some gas in it and suck it out through the fuel pickup with a plastic squeeze-bulb type transfer pump (DONT use anything ELECTRIC). I make sure that the sending unit gets to zero ohms before the pump sucks air. Then, if you suck all the gas out from that point until the pump cant suck any more, that is the size of your reserve. There will be a little gas in the bottom that you cant suck out. That is unavoidable.

Thats the long version.

If you don't have the tank out, and you don't wanna do the whole routine, try bending the arm so the float goes lower in the tank before the arm hits the stop.

I hear a lot of people complaining about aftermarket sending units these days. Good luck.

[chevy_mike]

Or you can use a long stick and check your fuel level. If the stick comes out wet, you still have fuel.

[WOLFMANmike]

Originally Posted by chevy_mike

Or you can use a long stick and check your fuel level. If the stick comes out wet, you still have fuel.

Lol no thanks can't tell how much that way it would be no different than now lol

[Railroader]

I didn't want to pull my tank so this is the process I used. Drain the tank. I used one of those "jiggling" hoses. Can't think of the proper name, got it at Walmart.

Gauge should read empty. Add one gallon of gas at a time, check gauge after each gallon. You can determine when it moves off empty and when it reads full.
When gauge reads full, keep adding gas (if you can) and you can see how much gauge is off.

Keep up how many gallons it took to move off empty and full reading. Adjust sending unit arm as needed. Repeat process until you get good readings.

Slow process but it will work. Make small adjustments to sending unit arm.