[19bonneville66]

My gas gauge stopped working recently, so I went an bought a new sending unit for 66 Bonneville I took the old one out an it looks nothing like the new one I got, the new one is to small, where do I find one to fit it? Guy at part store had no idea where or which one lol help?

[ELKHORNAOG7]

Look on the right side of this thread (vendors) look for (ROBBMC) -----BOB

[Txbobcat]

Also a guy in Hemmings in Calf will rebuild yours or make you another one.

[archerytony]

Originally Posted by ELKHORNAOG7

Look on the right side of this thread (vendors) look for (ROBBMC) -----BOB

Robbmc

[19bonneville66]

I found a sending unit I got it on summit, I just put it in hooked it up grounded it, I had put a new fuel gauge turned the key An nothing happened. I ran a wire from the battery to the gauge just to make sure it worked an it did, I'm not sure where to look now, everything worked fine before the issue I stopped to get gas an 3 days later it was at the same line still so I bought the New sending unit but it still isn't working. Any ideas?

[HWYSTR455]

Does the gauge peg when you turn the key, or does it not move at all?

If it pegs past F, it's an open at the gauge or the sending unit ground is bad.

If it doesn't move at all, or it pegs past E, it's a short at the gauge or power wire to the sending unit.

If it doesn't move at all, the gauge is bad. Or check the fuse.

Think I got those right, it's from memory, not sure how good my memory is these days though!

If you look at the service manual you will see a troubleshooting flow chart which will help isolate.

.

[19bonneville66]

with everything hooked up, when i turn the key on it doesn't move at all, i know the gauge works, ill check the fuse. i hooked the factory gauge up to see if it was still good an when i moved the needle it went back down past E, i moved it alittle past that an it went back up, still wasnt reading anything, i have gas in the tank to

[HWYSTR455]

If you ground the wire that goes to the sending unit, and the gauge goes full, then it's the sending unit, or the sending unit ground. If it doesn't move, it's the wire from the gauge to the sending unit, the gauge, or power to the gauge.

You can use an ohm meter to figure out if it's a power problem. Believe there's also a capacitor on the back of the dash that regulates voltage to the guages, but think if that were bad, all the gauges would be boogered.

Check the connection in the trunk from the rear harness to the sending unit, see if that's plugged in good. Can take a reading there too, see if it's from the connector to the dash or from the connector to the sending unit.

.

[19bonneville66]

put a new fuel sending unit in, grounded it, i bought a new gauge, made new connections, grounded the gauge, i ran a new sending wire from the sending unit to the back of the gauge, turned the key an still nothing,

i unplugged the sending wire from the sending unit, took a test light grounded it an stuck it in to the sending wire connector an the gauge went full, all my other gauges an gauge lights work, its a new sending unit, cant figure it out an its starting to be a pain in the butt dropping the tank everytime to get to the wire lol

[HWYSTR455]

Do you have the ground wire going from the sender to the body? If so, check the grounding of that, make sure it's getting a good contact, the wire is good, etc. If the ground is good, and you peg the gauge with the wire from the gauge grounded, it's a bad sending unit.

.

[19bonneville66]

ill check that ground, could it be that the sending unit that i have in there now is 0-90 ohms and the gauge i have in is 33-240 ohms? i bought a gauge yesterday that is 0-90 ohms that will match the sending unit so it should work then?

[HWYSTR455]

I'm actually not sure what the 66 uses ohm-wise, or what you bought, but if there's a mismatch, yeah, that could be it. Hook the sending unit up to the wire to the gauge and ground it, then move the float to test.

Isn't there OE sending units available for your car? Shoot, think even Rock Auto has them for like 30 bucks or something. Hope you got one that is model specific?

.

[19bonneville66]

Originally Posted by HWYSTR455

I'm actually not sure what the 66 uses ohm-wise, or what you bought, but if there's a mismatch, yeah, that could be it. Hook the sending unit up to the wire to the gauge and ground it, then move the float to test.

Isn't there OE sending units available for your car? Shoot, think even Rock Auto has them for like 30 bucks or something. Hope you got one that is model specific?

.

i couldnt find a sending like the one that came out of my tank, so i found one that looked like mine turned out to be from a 67 impala what they gave me, and it fit in my tank its 0-90ohms, so i was told get a gauge for 0-90 that should be the problem, they will match then. i hope it works,

i bought a sending unit for my car a 66, an when i got it.. it was way to small for the gas tank hole an the fuel line was different, the first picture is what i bought, they have another one for a 66 that looks like it will work but it has a return line, mine only has a fuel line, i looked at rockauto they only have those 2 units, an OPG has only those 2

[HWYSTR455]

Just plug the return line if it's the correct one.

I'm pretty sure your factory gauge is a 0-90 ohm unit, not sure why anyone told you to replace the gauge, they rarely go bad. I think 65 was the change over year, and those were 0-30 ohm range. I thought only the newer gauges and aftermarket stuff was the 240 ohm range stuff.

You said when you grounded the wire the original gauge pegged? If so, it's good.

.

[19bonneville66]

i put a new fuel gauge in 0-90, all new connections, its grounded, i ran a new sending wire to the sending unit, the sending unit is new i grounded it, an the only thing it did when i turned the key on was the needle went past full,

i took the tank all the way out pulled the sending unit out hooked it up, grounded it an moved the float by hand it still went past full,

so thats a bad sending unit? i boxed it back up an am sending it back today an getting the sending unit for my car,

i changed the gauge after i put the new sending unit in an it still didnt work i thought it might be the gauge, so i bought a new one to match my other two gauges, i still have the factory fuel gauge.

just gotta wait for the new sending unit now

[HWYSTR455]

Originally Posted by 19bonneville66

i put a new fuel gauge in 0-90, all new connections, its grounded, i ran a new sending wire to the sending unit, the sending unit is new i grounded it, an the only thing it did when i turned the key on was the needle went past full,

i took the tank all the way out pulled the sending unit out hooked it up, grounded it an moved the float by hand it still went past full,

so thats a bad sending unit? i boxed it back up an am sending it back today an getting the sending unit for my car,

i changed the gauge after i put the new sending unit in an it still didnt work i thought it might be the gauge, so i bought a new one to match my other two gauges, i still have the factory fuel gauge.

just gotta wait for the new sending unit now

Ok, you grounded the gauge? Maybe that's the problem. Or maybe the wires are swapped. So when the gauge pegs past full that means the gauge wire that goes from the gauge to the sending unit is grounded. Or the sending unit is bad, grounded internally.

To test the sending unit, use an ohm meter, red on the lead that goes to the gauge, black on the ground, and swing the float arm. It should go from 0 to 90. If it stays 0 regardless of how you swing the arm, it's grounded internally. If you get infinate, regardless of where you move the arm, it's open internally.

So that will eliminate the sending unit. Now the gauge. So when the sending unit plug/wire is unplugged/disconnected from the sending unit, the gauge should read empty. Grounded, it should read full, or actually, past full. If it reads any different than that, then you know it's the gauge, or the wiring to the gauge/sending unit.

.

[19bonneville66]

i finally got the right sending unit! frankspontiacparts.com they had the one i needed, i got it in the mail yesterday when i got home i wired everything up turned the key on an moved the float an it worked fine, 76$ an 5 wrong sending units later, i just have to run the new sending wire an put the tank back,

thank you everyone for your help an time i appreciate it

[HWYSTR455]

Woo-hoo! Great to hear!

.

[Txbobcat]

And you got all this done in less than a month. Many guys might have taken a year or two.