Fuel Gauge Reading

[Bayou Dave]

When I got my boat the fuel gauge always read empty with the key off and thought it seemed accurate with the key on. I have my interior out and decided to check the fuel sender and pulled the float out. Raising the float out of the tank the fuel gauge went down to empty. When I buttoned everything up the fuel gauge stays at 3/4 tank (which is about how much gas is in the tank) with key on or off. I never pulled any wires off except the green one which is under one of the screws. Any clue why it now doesn't go to empty with the key off? Does it even matter where the gauge is with the key off?
Thanks... Dave

 

[ajgraz]

Did you put the green wire back?

 

[Bayou Dave]

Did you put the green wire back?

Yes, but not sure it was the same screw I put it under.

 

[alldodge]

Think it just coincidence but the gauge may have taken a powder. Remove the wire off the sender and see if it changes. If not may need to remove the sender again to see if its hung, but this should still have no effect when power is off

 

[Bayou Dave]

Think it just coincidence but the gauge may have taken a powder. Remove the wire off the sender and see if it changes. If not may need to remove the sender again to see if its hung, but this should still have no effect when power is off

I will pull the sender wire off tomorrow and see if it changes on the gauge. Do you know if a gauge normally returns to empty when the power is off or stays where it when the power is on? I have seen some auto fuel gauges go to empty and some not with the key off.

 

[alldodge]

Most that I have seen all go to empty

 

[wrench 3]

Try tapping the gauge with your knuckle with the key off to see if the needle is stuck.

 

[Bayou Dave]

Try tapping the gauge with your knuckle with the key off to see if the needle is stuck.

Good idea. If that doesn't work I will take off the sender wire. If those don't work I will pull the sending unit again.

 

[Bayou Dave]

Good news, bad news. I tapped on the guage and it went to 1/2, tapped and then 1/4, tapped and then empty. Turned the key on and it is stuck on empty. Tapping will not move the needle. Any ideas how to unstick the needle?

 

[Silvertip]

The needle isn't stuck. The movement is bad. Time to replace the gauge.

 

[Bayou Dave]

The needle isn't stuck. The movement is bad. Time to replace the gauge.

That is going to suck.The fuel gauge is part of a cluster with Volts and Speedometer.

 

[alldodge]

Make sure you didn't loose a connection to the gauge before replacing it. Check for 12V and ground. Then ground the sender wire and it should peg full.

 

[Bayou Dave]

Make sure you didn't loose a connection to the gauge before replacing it. Check for 12V and ground. Then ground the sender wire and it should peg full.

Do these checks at the gauge?

 

[alldodge]

Do these checks at the gauge?

yes

With the gauge hanging, there is probably an issue, just check everything before spending money

 

[Bayou Dave]

yes

With the gauge hanging, there is probably an issue, just check everything before spending money

I did the following today.

Checked for power on the purple wire on the gauge I terminal and have 12v

Turned key on and grounded the sender wire at the gauge and sender. Went to full each time.

Hooked up test light from negative on battery and touched the sender wire at gauge. Light came on.

Tapped on gauge until it went to empty. Turned key on and it went to 3/4, which is about how much fuel is in the tank.

With key still on I took off the ground wire at the tank and gauge went from 3/4 to empty. Put ground wire on again and gauge went back to 3/4.

It appears that the gauge is reading correctly, but I have to tap it back to empty each time I turn the key off.

 

[alldodge]

have to tap it back to empty each time I turn the key off.

You can do that but the gauge movement is dragging as Silver mentioned. Look in the future to replace or if you can take it apart, might be able to free it up. I would guess it got some moisture in it and corroded some

 

[Bayou Dave]

Just had a thought. By removing the ground wire at the tank the gauge goes to empty when the key is on. Doing that detaches the ground wire from the sender. I guess it is possible that part of the sender in the tank is hitting something it shouldn't when the ground wire is connected. Think I will pull the sender and move it around a bit and see if that helps.

 

[alldodge]

Just had a thought. By removing the ground wire at the tank the gauge goes to empty when the key is on. Doing that detaches the ground wire from the sender. I guess it is possible that part of the sender in the tank is hitting something it shouldn't when the ground wire is connected. Think I will pull the sender and move it around a bit and see if that helps.

What your doing is the same as removing the sender wire from the gauge. The gauge sees max resistance and goes to empty, so its just working as it should. Don't see the sender being the issue, think it was just coincidence that the gauge messed up the same time you removed the sender. Could be you didn't notice the gauge hanging a bit, maybe not

 

[Bayou Dave]

What your doing is the same as removing the sender wire from the gauge. The gauge sees max resistance and goes to empty, so its just working as it should. Don't see the sender being the issue, think it was just coincidence that the gauge messed up the same time you removed the sender. Could be you didn't notice the gauge hanging a bit, maybe not

Got you. I probably never noticed it hanging. I have a spare opening in the dash and will just get a single gauge instead of spending big bucks to replace the fuel gauge, volts, speedometer cluster I have now.