Mine is empty when the gauge reads 1/4 tank. Don't ask how I discovered
Full Version: Fuel sender calibration
Is there such a thing?
Mine is empty when the gauge reads 1/4 tank. Don't ask how I discovered
Mine is empty when the gauge reads 1/4 tank. Don't ask how I discovered
Not really.
The light in the gauge should go on when there is only a gallon or two left in the tank. Hopefully that still works? If so, rely on it over the needle in the gauge.
The sender just varies resistance from full to empty. I forget which way is which; it might be that higher resistance is a lower reading on the gauge? The only way I can think of to calibrate it would be to add a resistor in series with the sender, or in parallel with it.
If the light isn't working, you should probably pull the sender out and check it over; possibly clean it up so the float moves smoothly.
--DD
The light in the gauge should go on when there is only a gallon or two left in the tank. Hopefully that still works? If so, rely on it over the needle in the gauge.
The sender just varies resistance from full to empty. I forget which way is which; it might be that higher resistance is a lower reading on the gauge? The only way I can think of to calibrate it would be to add a resistor in series with the sender, or in parallel with it.
If the light isn't working, you should probably pull the sender out and check it over; possibly clean it up so the float moves smoothly.
--DD
QUOTE(Dave_Darling @ Sep 20 2014, 01:37 AM) 
Not really.
The light in the gauge should go on when there is only a gallon or two left in the tank. Hopefully that still works? If so, rely on it over the needle in the gauge.
The sender just varies resistance from full to empty. I forget which way is which; it might be that higher resistance is a lower reading on the gauge? The only way I can think of to calibrate it would be to add a resistor in series with the sender, or in parallel with it.
If the light isn't working, you should probably pull the sender out and check it over; possibly clean it up so the float moves smoothly.
--DD
Rats! Essentially it either works or it doesn't. My light does still work so that's good but I want a reliable reading so I guess I'll get a new sender :-(
I think McMark did a write up on rebuilding the sender unit. You can try to clean the resistor wire with lacquer thinner and a que tip before getting more invasive. You need to carefully open the sender to get to it.
QUOTE(Mike Bellis @ Sep 20 2014, 12:04 PM)
I think McMark did a write up on rebuilding the sender unit. You can try to clean the resistor wire with lacquer thinner and a que tip before getting more invasive. You need to carefully open the sender to get to it.
Uber grood
I'll look for the thread.
That may not fix the problem. The gauge in my wife's SC was like that when we bought the car. The problem was the gauge, not the sender.
I suggest removing the sender, and measuring the resistance across the gauge output. (From "G" to the three-line ground symbol.) Check it with the sender right-side up, and again with it upside down. Someone here will remember the correct range; I think it's on the order of 90 ohms - 0 ohms? Verify that first. If that measures OK, then I would suspect the gauge. See if you can swap with someone else, or pick up a spare. You might be able to borrow one for testing.
--DD
I suggest removing the sender, and measuring the resistance across the gauge output. (From "G" to the three-line ground symbol.) Check it with the sender right-side up, and again with it upside down. Someone here will remember the correct range; I think it's on the order of 90 ohms - 0 ohms? Verify that first. If that measures OK, then I would suspect the gauge. See if you can swap with someone else, or pick up a spare. You might be able to borrow one for testing.
--DD
QUOTE(Dave_Darling @ Sep 20 2014, 12:11 PM)
That may not fix the problem. The gauge in my wife's SC was like that when we bought the car. The problem was the gauge, not the sender.
I suggest removing the sender, and measuring the resistance across the gauge output. (From "G" to the three-line ground symbol.) Check it with the sender right-side up, and again with it upside down. Someone here will remember the correct range; I think it's on the order of 90 ohms - 0 ohms? Verify that first. If that measures OK, then I would suspect the gauge. See if you can swap with someone else, or pick up a spare. You might be able to borrow one for testing.
--DD
Another good suggestion!
My tank is soon to come out (for a sway bar installation) so I can attack this at the same time :-)
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