Gas Gauge/Sender pissin' me off....

[SwitchBlade327]

I still don't have this straightened out. Someone school me on how exactly this shit is supposed to be wired up so i know if i got it right or if the sender is screwed up. I don't wanna siphon out this full and huge gas tank unless I'm sure it's necessary. I know the gauge is working correctly, but it's staying on empty the way it's wired right now, and the tank is damn near full up to the gas cap.

[36-3window]

i don't know what brand you have,but they all work about the same.the fuel gauge should have three terminals on it. one is ground,one is 12 volts + switched and the last goes to the sender. the sender in the tank should be grounded to the frame.


what gauges are you using? does the gauge and sender match? you can't mix and match these! stewart warner and VDO senders work opposite of each other. what happens when you take the wire off the sender? what happens when you take that wire and go to ground? it may just be your sender isn't grounded,check that too

[40StudeDude]

As I understand it...the gauge (and sending unit) works off "Ohms", if neither is matched to the same "Ohms", they simply won't work together...when you buy a set, make sure they are matched to each other...probably too late for you now...
R-

[Gr8ballsofir]

What make is it? On my 50 Buick, there is one wire going to the middle of the sender. The outside is grounded through the tank. The voltage goes from the battery, through the gauge and then on to the sender. The sender acts as a variable resistor which controls the amount of current that can travel through the guage. If the tank is full the float is in the up position and there is NO resistance, so the guage goes all the way up. If the tank is empty, the float is in the lowered position and there is TOTAL resistance, so the guage drops to zero.

An "easy" way to check is to connect an OHM meter between a ground source (BAT Minus or body screw) and the wire that goes to the gas tank (disconnected from the fuel guage). If your sure the tank is full, you should get Zero ohms on the meter. If there is some resistance then you probably have a broken wire or bad (dirty?) sender. I took mine apart and found it was dirty, cleaned it and it works great!!

[flt-blk]

Are you sure you're sending unit float didn't spring a leak and sink itself?
TZ

[SwitchBlade327]

it's the stock 60 pontiac gauge and sending unit. Got a voltage reducer on the gauge. I put a multitester on the sender and it read like .31 resistance, I don't know how full the tank is exactly, but i know it's closer to being full than it is to empty. There is only two places for wires on the back of the gauge. So i have the hot wire going in one side with the voltage drop on it, then the wire goes back to the fuel sender and is grounded from the sender as well. could i just have the wires in the wrong place on the gauge? If the wires were flipped around would the needle go the wrong way? The sender in the tank was grounded to the trunk floor originally it looks like, but I've got a temp grround while I'm checking to see if things are working or not. When I took the power wire loose, the needle would very very slowly start working it's way back towards Full.

[choprods]

Why the reducer?if stock guage and sender shouldn't it work without that?

[SwitchBlade327]

12 volts...

[Gr8ballsofir]

Try switching the 2 wires. DC voltage only works 1 way. If the wires are backwards your guage will peg on empty... Try setting your multitester on DC voltage and put it on the 2 guage terminals. See which way is positive. Is it digital or analog? It sounds like your guage is wired backwards.

[SwitchBlade327]

I'll feel REAL stupid if that's all the problem is, but I'll be happy at the same time. Won't be able to find out until monday though. Thanks guys.

[Gr8ballsofir]

How do you think I know that the meter goes backwards when the wires are reversed? We all learn from our mistakes. that's why I know so much!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[SwitchBlade327]

well found out i had it wired right, dropped the tank, sender seems okay, but the gauge is screwed. Put up a post in the classifieds lookin' for one. Shoulda known some little hard to find shit would pop up.