Fuel Gauge test?

[dkuehl]

I thought I had read it somewhere on this site about how to test the sender and gauge.. but now I can't find it...

I am looking for the pins in the fuel sender harness to cross to get the fuel gauge to move to see if it is the gauge or the sender.. The gauge reads empty all the time and I have not seen it move ever…

any help?

[bravekozak]

The fuel sender has a red wire for power and a black wire for ground. Ignore the black/white stripe wire, that is for power to the fuel pump motor.

[bravekozak]

Here are the approximate values you should be getting when you put your ohmeter across the red and black wires at the sender.

Empty, 95 ohms, arm down, high resistance
Half full, 32.5 ohms, arm level, medium resistance
Full, 7 ohms, arm up, low resistance

Usually, the most wear occurs in the middle of the resistance wire windings. That is where the break normally happens. Most members find they have a reading when the tank is full. but it drops below empty when the level falls below half a tank.

In your case, where there is no needle movement, check to make sure your fuel sender is getting power to the red wire with a 12V test light. If it is then, check the resistance with an ohmeter. If the resistance is O.K., then test your fuel gauge. Good luck.

[bravekozak]

NOS parts still show one fuel level sender remaining in stock.
It's pricey. But, you have to ask yourself if you want another twenty years of knowing exactly how much gas you have left in your tank.

[bravekozak]

Those with carb senders have to go to Four Green.
KK14260960B

[needragr]

I have a 89 L that had a tach cluster conversion in it by the PO. I am recognizing that the gauge needle NEVER moves off empty.
Are there differences in the two clusters that the PO never wired, resulting in this situation or is it still just the sender, gauge, or wiring that I should focus on to troubleshoot?

[william]

No difference in clusters I would suspect the sender.
But could be a wire.

[needragr]

& the only way to test it is to pull out the R. seat & carpet?

[navdoc101]

Why not try pulling the guage cluster & cleaning/ sanding all the pins.
Worked on mine.

[needragr]

Here are the approximate values you should be getting when you put your ohmeter across the red and black wires at the sender.

Empty, 95 ohms, arm down, high resistance
Half full, 32.5 ohms, arm level, medium resistance
Full, 7 ohms, arm up, low resistance

Usually, the most wear occurs in the middle of the resistance wire windings. That is where the break normally happens. Most members find they have a reading when the tank is full. but it drops below empty when the level falls below half a tank.

In your case, where there is no needle movement, check to make sure your fuel sender is getting power to the red wire with a 12V test light. If it is then, check the resistance with an ohmeter. If the resistance is O.K., then test your fuel gauge. Good luck.

I would assume this is the same for FI senders as carbed? I just pulled a sender from the 89LX Im striping, tested at the lowest range of my meter (200ohm) ,,, No reading (open) at empty, 1/2, and only at the top do I get any change in resistance.
Can I crack one & fix it before I tear into my driver to troubleshoot & possible replace?

[bravekozak]

Thread 41962

[needragr]

10 pages! Thanks that is exactly what I found: windings wiped out.
On a positve note I tore into the driver, pulled the sender & it tested- ok.
Checked continuity of the yellow wire to the connector under the dash & that is ok.
SO I must have a bad gauge?
I pulled the cluster and found all manner of mayhem had taken place.
for whatever reason the PO had ripped open further the hole stamped in the support directly behind the cluster and had also attached wires to the 3 vertical screws on the back , when traced through the firewall two were attached to either side of the coil? WTF!

[needragr]

well its time to update this progress thread.
i figured out the wiring issues got my cluster working, installed the other sender and ....it works! Sort of...
if tank is full it shows .5 full on the gauge.
its better that no gauge but itll only read for about 200 miles then its buried.
Q: has anyone taken the sender element out of a late sender and transplanted it into an early carb sender? Or are those parts the same?

[FestYboy]

The sender is the same, so if you have a good one from an EFI car, it will swap over.

[needragr]

Thx well one popped up @ my local Pick n Pull, so I took a chance.

FAIL