gas gage not reading correct

[Perry C]

I have a 1986 c10 with dual tanks, I can hear the switch change the tank selector valve but the fuel gage only reads 1/8 on the left and 1/4 tank on right and both are over half. any ideas? thanks in advance.

 

[supercharged]

My guess would be a poor ground. If it changes readings from left to right tank.
How do you know for sure their over half full ?

 

[HotRodPC]

Jepper, 1st and usually is the most common fuel gauge issues, is check the grounds. Not only tight, make sure they're clean and not broke.

 

[Perry C]

gas gage

I cleaned the grounds that I found they were good not broke I couldn"t get to the connections on the sending unit.

 

[HotRodPC]

I cleaned the grounds that I found they were good not broke I couldn"t get to the connections on the sending unit.

It could be those too. How about this truck as far as sitting for any length of time with bad gas in it in it's history? Sometimes the sending units can be jacked up gunk and ****.

 

[Perry C]

I just traded for it so I don't really know the history or how long it may have been sitting. I think it was being driven daily. Another problem it has is It idels up and down at different times I thought at first the electric choke but I watched while it did it and the choke never ingaged. It does have a plug on top of the carb that I'm not sure what that controls. I wondered if the selector valve was opening and closing properly I can hear it and the gage changes somewhat.
Never had so many opitions on what could be wrong with fuel gage. Can I undo the wire from the fuel selector and ground out any certain combination of the wires to check the ful gage and switch it self?

 

[HotRodPC]

That ideling up and down can also be a dirty EGR valve. Just take it off and clean the port and the pintle. Make sure it's able to open and close without any carbon build up in the way.

 

[MrMarty51]

unplug wire from sending unit = guage should move{I dont remember if full or empty}.
Ground wire to sending unit = guage should move {read above upper comment}.

 

[MrMarty51]

unplug wire from sending unit = guage should move{I dont remember if full or empty}.
Ground wire to sending unit = guage should move {read above upper comment}.

Then,if a feller knew what resistors,or,had a variable carbon pile resistor,they could check the guages for accuracy.

If the guage needle moves with the above prescribed test,it then is either a bad ground or a bad sender{s}.

 

[fallguy]

Sending unit

It could be those too. How about this truck as far as sitting for any length of time with bad gas in it in it's history? Sometimes the sending units can be jacked up gunk and ****.

Had the same issue. Had to drop tank (easy to do) and replaced sending unit on top of tank...also easy. Make sure tank is empty & to save yourself a MAJOR PIA...make your fuel lines 2' long to the sending unit & coil wen you put take back up into place....the factory 4" lines can only be reinstalled by a magician....with rubber bones in his arm!!!

 

[philjafo]

If the bolts holding the bed on aren't rusty there's only 8 and the bed comes off easy. Easier then dropping a tank with a lot of fuel in it anyway.

 

[HotRodPC]

If the bolts holding the bed on aren't rusty there's only 8 and the bed comes off easy. Easier then dropping a tank with a lot of fuel in it anyway.

Especially if you're working on both tanks and while there, may as well replace all the fuel lines. It's certianly worthy of doing a good, neat and thorough job. 2 strong guys or 4 sissies can lift the bed off.

 

[Perry C]

well I unplugged the fuel selector valve and the gas gage goes to full I tried grounding out the 3 pink or look pink but it didn't change the gas gage. pulg the fuel selector back up select right tank 1/4 tank left tank does go to empty from an 1/8 tank but I've dove a couple of days on the left tank.

 

[HotRodPC]

well I unplugged the fuel selector valve and the gas gage goes to full I tried grounding out the 3 pink or look pink but it didn't change the gas gage. pulg the fuel selector back up select right tank 1/4 tank left tank does go to empty from an 1/8 tank but I've dove a couple of days on the left tank.

So what's all that mean???

 

[Perry C]

Could it be the selector valve or does that narrow it down to the sending units? I can hear the valve switch but could it have a short in it not reading the fuel sending units right?