gas guage question

[englands 71]

I put a new tank between the bed rails.
Spliced into the existing fuel gauge wire and ran it to the new sending unit.
Put gas in it and it reads empty.
I took the ground wire off to check my ground and the gauge went past full. Re-connected the ground and it goes to empty. So I know the gauge works . Has a new sending unit . What the Crap ? Any suggestions ?

[summitflier]

Stock gauge?

Is sending unit 30 or 90 ohm?

[BrianG]

Originally Posted by summitflier

Stock gauge?

Is sending unit 30 or 90 ohm?

x2 on checking the ohms of the new sending unit. It won't read right if they are not the same

[englands 71]

Originally Posted by summitflier

Stock gauge?

Is sending unit 30 or 90 ohm?

I'm not sure of the ohm . If mine is reading empty , what would that mean that my ohms is ?
And what would I need to do to correct it ? The tank is a replacement from SOKY Classics, blazer tank. I told them it was going in a 71 and that is what they sold me.

[englands 71]

Originally Posted by BrianG

x2 on checking the ohms of the new sending unit. It won't read right if they are not the same

so what ohms is mine if its reading empty. and what do I do to correct it.

[englands 71]

I haven't checked it yet but I called soky classics and they its a 90 ohms unit.

[summitflier]

If you're using the stock factory gauge, it should be 90 ohm.

[englands 71]

Originally Posted by summitflier

If you're using the stock factory gauge, it should be 90 ohm.

its the factory guage and a 90 ohm sending unit.
Funny thing happened a minute ago.
The brown wire running to the fuse box has a factory type tan colored plastic shield over it. Looked original. I took it off and hooked it up and my gauge went to an 1/8th of a tank which is about what I'm guessing is in it. I'm going to go get a little gas and see what happens.

[englands 71]

I put $10 worth of Premium in it but cant tell if it moved any. After I get the carb back on it ill drive it down and fill it up and see what happens.

[bigbadchev72]

Every aftermarket fuel sender I have put in has had the float sink within a day or two if they are the copper ones. Is it a plastic tank? If so you will need to also ground the metal portion of the sending unit. you will have no reference to ground other wise

[englands 71]

Originally Posted by bigbadchev72

Every aftermarket fuel sender I have put in has had the float sink within a day or two if they are the copper ones. Is it a plastic tank? If so you will need to also ground the metal portion of the sending unit. you will have no reference to ground other wise

I'm not sure that I understand. The plastic tank came with a ground wire that I grounded to the frame. Are you saying that I need to run another ground? Where from the tank would I start a ground wire ?

[BrianG]

If you can get to the sending unit, take it out then while making sure it is grounded, move the float up and see if the gauge changes at all. If it does, take the float out and test it to make sure that it floats.

[englands 71]

I took the white plastic cover off the brown wire where it hooks to the fuse block. Cranked up the truck today and the gauge moved to a little ove a 1/4 tank which is what I think it should have in it. I think the trouble was the clip.

[englands 71]

The gas gauge moved to way past full today ....WTH ?

[T.B.A.]

IIRC, if your gauge reads over full, the sender wire has probably been grounded somewhere between the fuse panel and the tank.
If you can get to the sender, try running another wire out through the door etc, just for testing purposes. I had to run a new wire, as the original was brittle.