Fuel float sending unit question

[Wings65288]

I got a question for you guys, can you test the fuel sending float without actually turning the car on? I just wanted to make sure the float was still working before I put the tank on so I "keyed on" the car and had my son hold the float up in the full position. When I keyed on my dash said my tank was empty even though he was holding the float all the way up. (yes i had the hat plugged into the harness). Thanks guys!

 

[robvas]

How long did you wait? When I fill my car up it takes a couple minutes for the gauge to catch up

 

[Wings65288]

How long did you wait? When I fill my car up it takes a couple minutes for the gauge to catch up

Mine usually is pretty quick so I'd say we sat there for about 30 seconds. But again we aren't able to start it up right now because the fuel tank is out. I'm only able to "key-on".

 

[2003RedfireVert]

It’s probably just a resistor. You can measure the voltage at the pins to see if it changes while you move the float up and down. Make sure it’s getting power and has ground. If the volt reading is changing at the pins but not showing at the guage, keep tracking back to the guage.

My guage changes immediately when I turn the key to the on position.

 

[03' White Snake]

I’ve done this, yes you can check it out of the car. It does take a little bit to respond on the gauges though. Make sure the float is not bending the contact inside the sending unit and not making contact.

Look inside the sending unit, is the yellow wire still attached? If not, carefully open it up and you can re-solder the connection. It is a very simple unit. I repaired mine a few years ago.

 

[Nate14120]

Just commenting that mine has always shown on the dash quickly. Just went through it today actually. Not 100% sure if it's matters but the ground from the sender should be the middle hole.

Pics because why not.

Sent from my SM-N960U using Tapatalk

 

[beau t]

Dose your gauge sweep full and then empty when the key is cycled?
Or did you let the float down to see if it went to full maybe got wires crossed? Worth a shot .

 

[Wings65288]

Dose your gauge sweep full and then empty when the key is cycled?
Or did you let the float down to see if it went to full maybe got wires crossed? Worth a shot .

Yeah I'm going to get a new sending unit. Where would you guys tho

I’ve done this, yes you can check it out of the car. It does take a little bit to respond on the gauges though. Make sure the float is not bending the contact inside the sending unit and not making contact.

Look inside the sending unit, is the yellow wire still attached? If not, carefully open it up and you can re-solder the connection. It is a very simple unit. I repaired mine a few years ago.

Great tip thank you, soldered it back on. The problem wasn't even the fuel pump it was a bad relay on the wiring harness for one of the pumps. I shoulda checked this first oh well. Funny thing is the relay would work for 2 seconds then shut off. I bench tested it and it was checking out fine and it wasn't until I "key-on" the car and plugged/unplugged the relay to find the problem. She's off jackstands again that's all that matters (knock on wood).