Converted to a center fuel gauge a while ago. I knew the old sending unit was bad because it would never read over 1/2-3/4 of a tank with the old gauge or new center gauge. So I replaced the sending unit tonight get everything hooked up and "BAM" gauges reads empty. If I remove the brown wire in the trunk it jumps over full the way it should. Is this brand new sending unit bad or am I missing something? Please help before I go nuts.

Converted to a center fuel gauge a while ago. I knew the old sending unit was bad because it would never read over 1/2-3/4 of a tank with the old gauge or new center gauge. So I replaced the sending unit tonight get everything hooked up and "BAM" gauges reads empty. If I remove the brown wire in the trunk it jumps over full the way it should. Is this brand new sending unit bad or am I missing something? Please help before I go nuts.


Wire connections reversed on new sending unit???

Nope, two different terminals can't make that mistake.

How about the connections on the fuel gauge,is it possible those got switched when you did the gauge conversion?Or it could be a faulty ground.

Everything worked after the conversion as it did before it. The only reason I changed the sender is because I never had an accurate reading, now it is just on empty. As for the ground, it is grounded in the same manner it was prior. I do not want to have to drop the tank again.

Get yourself a 0-100 or 0-500 ohm potentimeter, or a resistor box and wire it to the tan wire at the sending unit, removed from the unit, and ground.

Vary the resistor from 100 ohms down to zero and watch the gauge follow, 90 ohms full, 45 ohms, half tank, 25 ohms 1/4 tank.

Get yourself a 0-100 or 0-500 ohm potentimeter, or a resistor box and wire it to the tan wire at the sending unit, removed from the unit, and ground.

Vary the resistor from 100 ohms down to zero and watch the gauge follow, 90 ohms full, 45 ohms, half tank, 25 ohms 1/4 tank.

I will be doing that tomorrow. Thanks. How often does one get a bad sending unit.

I personally am still using my OE unit, so I wouldn't know.

What you've got is either a bad sending unit or it is incorrectly installed.

One thing that can happen is, if you're not super careful in keeping the locking ring centered, it can shift to the side a lil, and touch the terminal where the tan wire connects, grounding it out.

Your test is showing you that you are grounding out "downstream" from that connector in the trunk. I'm afraid you're gonna have to pull the tank again.

What you've got is either a bad sending unit or it is incorrectly installed.

One thing that can happen is, if you're not super careful in keeping the locking ring centered, it can shift to the side a lil, and touch the terminal where the tan wire connects, grounding it out.

Your test is showing you that you are grounding out "downstream" from that connector in the trunk. I'm afraid you're gonna have to pull the tank again.
Good call Jim. He say it reads empty but my first thought is when grounded it would be below empty. I dunno:confused: I used to put a test light in there and they read about half generally.

Jeff

Well I have the tank half down (can't bring it all the way alone with the gas in it) I was able to remove the tan wire and everything there seems fine. Regrounded it that all seems fine. Gauge in the dash tests fine. So I got a bad sending unit (yipee). Now I know why NOS parts are so expensive, pay up front for the good part and save on the double labor and couple of six packs for a buddy to help.

I don't know which sending unit you bought, but the $49 "repro" unit I bought from Rick's was no good out of the box (float arm binding in the mechanism; the coil was cheap and the housing wasn't any better). I bought the $79 Spectra Premium unit from RockAuto.com and it works perfectly.

$49 unit from Ground Up. That is all I can find with the two lines unless I want to pay near $300.

http://www.rockauto.com/catalog/x,carcode,1034738,parttype,4436

SPECTRA PREMIUM Part # FG104D
Includes Fuel Sender, Float and Strainer (Fuel Pump Not Included); 2 Outlet
$73.79

Thanks Eric. I swear they didn't have that one month ago I checked before I went to Ground Up.

Found the problem, Okay my bad I guess. When I removed the unit from the tank it revealed the insulation on the flat wire that goes from the rheostat to the terminal had been pulled down the wire and it was grounding out on the inside of the unit.
So I wound up taking apart the old rheostat cleaning the contact and taking the float from the new one putting on the old one (old float didn't look to good) tested and bingo, good to go.
Thank you to all for your help.