Two wire fuel sending unit

[uncleaud]

Is there a quick and easy way to check the sending unit with it out of the tank? I have current at both wires but don't get any response at the gauge when I move the float up and down or when I touch the two wires together. Wait a minute. the light bulb just come on in my head. If the unit is out of the tank I may need a jumper wire from the unit to ground.  I'll be back!!

[joecoozie]

Yep.

Needs  ground to the flange.

[Sniper]

Just remember that gauge works by differing magnetic fields so it is immune to voltage differences,ie 6 vs 12v.

 

But yes, you need to ground both the sender AND the gauge.

[uncleaud]

Ok...I tried that and it didn't change anything, right now the needle reads empty. Can I ground out a wire at the sender and get it to move like a single wire sender?

 

Shouldn't I get an ohm reading between the contacts on the sender?

[Veemoney]

Here is how I tested the set-up out of my 47 WC.

Below the testing info is the proper hook-up of your gauge according to the Motors Manual. It does not show the gauge needs to be grounded and during my testing I did not ground the gauge but it doesn't hurt anything if you do. It is important that the gauge sits upright as it would in the dash for balance. Also note the gauge does take a bit to warm up before the needle moves so don't expect it to jump when you give it power.

 

1. Make sure the sending unit flange is level and grounded to the battery. I had a tough time getting a good ground at the flange.
2. Carefully clean the points of the gauge by pulling bond paper through the closed set
3. Gauge does not require ground but should be upright as if it were in the dash so the balance is correct. 
4. Set float on gauge up near the position it would be when the tank is full
5. Use jumper wires to connect numbered terminals first 
6. Hook up power with jumper wire from 6v battery to Ign SW terminal on gauge.
7. Give it a minute or 2 to warm up and start moving to full if it moves great
   1. If not check sender ground and try it at a couple positions mine was touchy
   2. Move the float 1/4 inch to see if this gets a reaction
8. Next position the float as if the tank was empty. You can measure the gas tank from the flange to the bottom of the tank to get the position. and see if the gauge responds correctly.
9. You can hook up an ohm meter to terminals 1&2 and check to see as you move the float arm if the resistance changes. it should and if not the resistance windings could be dirty, distorted or not making contact with the float arm which takes the current to ground. I disassembled my sending unit and the windings were full of crud as well as distorted. The arm contact needs to rub lightly on the windings, mine needed to be bent out slightly to make contact. Once cleaned adjusted and assembled it worked.

 

Edited May 5, 2023 by Veemoney

[bacelaw]

I just went through this and ran a ground wire under one of the mounting screws to the frame.  Solved all my issues.  Moparpro did send me a fuel sender that was bad out of the box - swapped it out and all is well...

[Semmerling]

3 hours ago, Veemoney said:

Here is how I tested the set-up out of my 47 WC.

Below the testing info is the proper hook-up of your gauge according to the Motors Manual. It does not show the gauge needs to be grounded and during my testing I did not ground the gauge but it doesn't hurt anything if you do. It is important that the gauge sits upright as it would in the dash for balance. Also note the gauge does take a bit to warm up before the needle moves so don't expect it to jump when you give it power.

 

1. Make sure the sending unit flange is level and grounded to the battery. I had a tough time getting a good ground at the flange.
2. Carefully clean the points of the gauge by pulling bond paper through the closed set
3. Gauge does not require ground but should be upright as if it were in the dash so the balance is correct. 
4. Set float on gauge up near the position it would be when the tank is full
5. Use jumper wires to connect numbered terminals first 
6. Hook up power with jumper wire from 6v battery to Ign SW terminal on gauge.
7. Give it a minute or 2 to warm up and start moving to full if it moves great
   1. If not check sender ground and try it at a couple positions mine was touchy
   2. Move the float 1/4 inch to see if this gets a reaction
8. Next position the float as if the tank was empty. You can measure the gas tank from the flange to the bottom of the tank to get the position. and see if the gauge responds correctly.
9. You can hook up an ohm meter to terminals 1&2 and check to see as you move the float arm if the resistance changes. it should and if not the resistance windings could be dirty, distorted or not making contact with the float arm which takes the current to ground. I disassembled my sending unit and the windings were full of crud as well as distorted. The arm contact needs to rub lightly on the windings, mine needed to be bent out slightly to make contact. Once cleaned adjusted and assembled it worked.

 

 

 

This is a perfect example of something that well written and topic specific enough that it should be recast in its own thread with a searchable title.

 

Thank you for putting this out here

[greg g]

Bad out of the box describes a lot of electrical items from China and Mexico.  I have the sender from the aforementioned vendor.  It wakes up, goes to about 3/4 full, waves at me, then drops to empty.  Does this regardless of amount of fuel in the tank. Once in a great while, when driving,  if by chance I am looking at the gauge, it may reflect actual fuel level. But never for more than 30 seconds.  I got it through a third party, after he got his original  working as it should. It does have a dedicated ground wire.  I am hesitant to play with it for fear of messing up my original trunk mat.

[uncleaud]

I run the test as shown above and didn't, get any results so I bit the bullet and drilled the rivets out of the top and took it apart, found a small copper piece that had popped off the end of the resistance winding. I clamped  it back over the rivets that it popped off of and give it a little solder to hook it back where it belonged. Cleaned it up a little and put it back together. Presto change, it works again. Love it when a plan comes together.?