["QUICK-SILVER"]

I do think you need to try another meter. Numbers you're posting are not matching up with logic or what they should be.
Sending unit rheostat range is probably going to be 0-30 ohms or 0-35 ohms. Have seen both listed for sale for the "64" model...along with 0-90 and 10-90. The ones that go up to 90 are listed as fitting "64" to "67". The 30 and 35 are "64" only.

Numbers:
.8 VDC in the rear we'll come back to.
11.8 VDC going to the guage is what's to be expected.
Now then, the guage has three connection points: power supply (B+), ground (B-), and the one that goes to the sending unit.
2.8VDC??? what could that be We've got two points on the guage unaccounted for so far, ground and sending unit wire. Ground would ohm out at 0/zero ohms (ground to ground = 0) and sending unit wire. Now 2.8VDC sounds alright for the sending unit wire, BUT, it checked .8VDC at the back of the car.

So, numbers are not adding up. The voltage drop from front to rear, if it is the 2.8VDC, would definitely be a problem. But you stated that the guage wouldn't drop back to empty even when grounded up front. This sounds like two problems.

Try another meter and retest things. Besides the B+ on the back of the guage there is stud that has a voltage regulator (flat, wire wound, resistor) between it and B+.
Need the B+ reading, opposite end of regulator reading, and sending unit out reading. Sending unit coming out of the guage may be the same as regulator drop reading. And the sending unit out of the guage reading should be the same at the back of the car .

Enough for now
Clay

[AdamIsAdam]

Clay,
I couldn't agree more and have already planned a trip to Home Depot for a new gauge (I have gift certificates there, so I'll buy a nice, auto-adjusting gauge).

Just to be clear, I've got a two wire "harness" type plug at the back of the fuel gauge. I measured both wires. One is clearly the B+ in showing switched power of 11.8 VDC, the other goes to the sending unit, which I got 2.8VDC. I got about the same reading at the junction behind the seat on that wire.

What's troubling is the .8VDC at the gas tank. I examined the wire from the junction to the tank and it looks fine. I was tired and it was late, so I stopped short of putting a jumper wire at that section.

But I feel that I'm not getting accurate readings with my cheap Sperry Multimeter. So I'll buy a better meter and start again.

But, why the heck is my gauge not going to E when I ground the sending unit wire right at the gauge or when I grounded it at the junction behind the seat? Regardless of my readings, why won't it ground to "Empty"?

I'm not totally clear on this:

Besides the B+ on the back of the guage there is stud that has a voltage regulator (flat, wire wound, resistor) between it and B+.
Need the B+ reading, opposite end of regulator reading, and sending unit out reading. Sending unit coming out of the guage may be the same as regulator drop reading. And the sending unit out of the guage reading should be the same at the back of the car .

[Pepi]

Originally Posted by AdamIsAdam

Clay,
I couldn't agree more and have already planned a trip to Home Depot for a new gauge (I have gift certificates there, so I'll buy a nice, auto-adjusting gauge).

Just to be clear, I've got a two wire "harness" type plug at the back of the fuel gauge. I measured both wires. One is clearly the B+ in showing switched power of 11.8 VDC, the other goes to the sending unit, which I got 2.8VDC. I got about the same reading at the junction behind the seat on that wire.

What's troubling is the .8VDC at the gas tank. I examined the wire from the junction to the tank and it looks fine. I was tired and it was late, so I stopped short of putting a jumper wire at that section.

But I feel that I'm not getting accurate readings with my cheap Sperry Multimeter. So I'll buy a better meter and start again.

But, why the heck is my gauge not going to E when I ground the sending unit wire right at the gauge or when I grounded it at the junction behind the seat? Regardless of my readings, why won't it ground to "Empty"?

I'm not totally clear on this:

Are you sure you are getting a good ground for your meter back at the tank? Maybe try to run a wire all the way to the battery neg for your meter so you know you have a good ground, or the same place you are using when you check the junction behind the seat.