66 Buick riviera gs gas stuck on empty

[BoLo]

Ok so at some point my gas gauge did work when I first got my car last year may 21 but it was sporadic cause sometimes it would work when I was full it would be good then it would go straight to empty like mid drive 

 then upon always filling up I noticed a leak when at full so I saved up got a new tank and fuel sending unit ran a verified chassis ground before putting the unit up I made sure it worked I also made sure I had 12 volts at the tank I did a test with a light and a test with multimeter (note with multimeter light was visible dim as in comparison so another Random check where it was very bright BUT still was at 12  need never budged I’m stumped helpppp

[61polara]

Did you test that the new sending unit was actually good before you installed it?  Did you test that the gauge actually worked while you had the wires disconnected?  One or both of these are at fault.

[Dandy Dave]

You need the check the sending unit in the tank with a olms reading. Best to take it out when you do that. A lot of times the problem is with a bad ground that won't send a signal to the gauge, or it could be that the tank float has sunk. I think your next move is to check the wires and gage. 

Edited March 7, 2022 by Dandy Dave (see edit history)

[joe_padavano]

17 minutes ago, Dandy Dave said:

You need the check the sending unit in the tank with a olms reading. Best to take it out when you do that. A lot of times the problem is with a bad ground that won't send a signal to the gauge, or it could be that the tank float has sunk. I think your next move is to check the wires and gage. 

^^^This. The stock sending unit reads 0 ohms empty and 90 ohms full. Check that from the sender wire to chassis ground. The ground wire from the sender is held with a ring terminal and a sheet metal screw, and rust there will cause a problem. The wire to the sender isn't a power wire, it's a wire to ground for the sender. If you are reading voltage there it's because there is no load on the circuit.

 

One easy test to see if it's the sender or the gauge is to disconnect the sender wire in the trunk. With the wire disconnected the gauge should read FULL, or even past full. Now ground the wire to the gauge. The gauge should read empty. If that works, the problem is the sender (or wiring to it). If that test doesn't work, the problem is the gauge or wiring to it.

[BoLo]

61polara

 

yes sir originally I had it in the tank but what I did was I took it out and checked it it read at 90 ohms and zero so it worked perfect it was brand-new but I still checked 

[BoLo]

2 hours ago, joe_padavano said:

^^^This. The stock sending unit reads 0 ohms empty and 90 ohms full. Check that from the sender wire to chassis ground. The ground wire from the sender is held with a ring terminal and a sheet metal screw, and rust there will cause a problem. The wire to the sender isn't a power wire, it's a wire to ground for the sender. If you are reading voltage there it's because there is no load on the circuit.

 

One easy test to see if it's the sender or the gauge is to disconnect the sender wire in the trunk. With the wire disconnected the gauge should read FULL, or even past full. Now ground the wire to the gauge. The gauge should read empty. If that works, the problem is the sender (or wiring to it). If that test doesn't work, the problem is the gauge or wiring to it.

it’s got to be the gauge wiring

I chose the chassis ground that I knew was solid and  checked it Before actually putting it all back in the tank  i spliced that’s together with my positive feed so it’s got to be something in the cluster something in a gauge that’s not telling the gauge what the fil sender is doing 

[BoLo]

3 hours ago, 61polara said:

Did you test that the new sending unit was actually good before you installed it?  Did you test that the gauge actually worked while you had the wires disconnected?  One or both of these are at fault.

No sir I checked these from the jump because I read many articles about the situation 

[BoLo]

The gauge fuel cluster is merely just like a grid on the backside no wires connected to it so what is the actual process of determining if my fuel gauge is bad I know exactly how to get back there but once you open the dash and look down it’s green style grip no wires connected in the back 

[BoLo]

Not mine but this is just how it looks 

but in my dash 

[Bloo]

11 hours ago, joe_padavano said:

One easy test to see if it's the sender or the gauge is to disconnect the sender wire in the trunk. With the wire disconnected the gauge should read FULL, or even past full. Now ground the wire to the gauge. The gauge should read empty. If that works, the problem is the sender (or wiring to it). If that test doesn't work, the problem is the gauge or wiring to it.

^^Exactly this.

 

8 hours ago, BoLo said:

it’s got to be the gauge wiring

I chose the chassis ground that I knew was solid and  checked it Before actually putting it all back in the tank  i spliced that’s together with my positive feed so it’s got to be something in the cluster something in a gauge that’s not telling the gauge what the fil sender is doing

 

I'm not quite sure what you mean. The insulated terminal or wire coming out of the sending unit connects to the wire heading to the front of the car. The ground wire from the chassis connects to the metal part of the sending unit or tank. Is that what you have?

 

[BoLo]

1 hour ago, Bloo said:

^^Exactly this.

 

 

I'm not quite sure what you mean. The insulated terminal or wire coming out of the sending unit connects to the wire heading to the front of the car. The ground wire from the chassis connects to the metal part of the sending unit or tank. Is that what you have?

 

Yes the ground with the ring is on a good chassis ground  

the other wire is connected where the original was I cut it cleaned it up and used a waterproof but connector the ones where u use a lighter to seal it 

as I followed it it goes into a harness with other wires up to the front and connects into another harness 

 

 

I was able to check voltage I have 12 volts going to the hot side on my gas gauge 

Olhms I went to ground 0 resistance  constant beep

i tested the ground to ground and got 0 resistance constant beep

i couldn’t test ground to hot today but will

tomorrow  

 

but I see what u guys mean I will disconnect sender tomorrow and then ground it

And see what happens