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Sending unit part 2

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steve from staten island

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So i have a gas gauge that was checked out to be in working condition, a original Mopar sending unit refurbished by a reliable vendor, new wiring, proper ground and with close to ten gallons ( good nine gallons)in tank and it registers a 1/4 tank at the gauge. Honestly dont know what else to do.
 
Sounds like you "just" need to bend the float arm? (Like a toilet!) Not what anyone wants to do, I know..but it worked for me. My aftermarket unit only read 1/2 on the gauge, when the gas was visible at the level of the filler neck.
 
beanhead said:
Sounds like you "just" need to bend the float arm? (Like a toilet!) Not what anyone wants to do, I know..but it worked for me. My aftermarket unit only read 1/2 on the gauge, when the gas was visible at the level of the filler neck.
Click to expand...
Dang.... I'm basically in the same boat as Stanton. My gas gauge didn't work for 20 yrs. (not hooked up), so I don't know how good it is.

New aftermarket sender, reads 1/2 tank when full. Cleaned ground & put in new strap, reads 1/2 when full. Put in an additional ground wire, reads 1/2 when full. Installed a used, correct sender, reads 1/2 tank when full. I bought a reproduction gas gage (only original gage left in my dash).... so I'm hoping that's it, or I'm out of ideas too. I guess it could be the toilet bowl idea, but TWO senders? I still have the original tank in my car.
 
Instead of doing the parts swap method of trying to fix stuff, why not do it properly and get the resistance specifications of your sender, test it with an ohm meter and see if it measures the proper resistance at empty, 1/2, and full. Then why not get some resisters that match the sender resistance or what the Chrysler gauge tester used to check empty, 1/2, and full and apply voltage across the gauge with the resistors in place and see if it reads properly. There is a thread on here somewhere that has all the resistance values needed to perform these checks.
 
Idrivemopar makes a good point, this should be checked before installing. If you get good readings moving the sender arm on the bench, (should read 9-10 ohms full and around 60-70 when empty) you know at least that the sending unit function is good. That leaves float arm adjustment, gauge, or wiring problem. A good quick gauge check is to ground the sending unit wire, turn the key on and back off, the gauge should peg full. In Steve's case it seems all these can be ruled out, leaving only the float arm adjustment.. @PurpleBeeper you can try the quick gauge test to make sure the gauge works, and then temporarily run a piece of wire from your gauge wire under the dash down to your sending unit(bypassing the existing wire)...to rule out high resistance in the wire, especially if it's old
 
idrivemopar said:
Instead of doing the parts swap method of trying to fix stuff, why not do it properly and get the resistance specifications of your sender, test it with an ohm meter and see if it measures the proper resistance at empty, 1/2, and full. Then why not get some resisters that match the sender resistance or what the Chrysler gauge tester used to check empty, 1/2, and full and apply voltage across the gauge with the resistors in place and see if it reads properly. There is a thread on here somewhere that has all the resistance values needed to perform these checks.
Click to expand...
I would have thought the guy who redid my unit would have done that as i paid him well. Were would the resistor be soldered in?
 
I agree with idrivemopar and beanhead. If you do everything they say you should be in business.
 
beanhead said:
Idrivemopar makes a good point, this should be checked before installing. If you get good readings moving the sender arm on the bench, (should read 9-10 ohms full and around 60-70 when empty) you know at least that the sending unit function is good. That leaves float arm adjustment, gauge, or wiring problem. A good quick gauge check is to ground the sending unit wire, turn the key on and back off, the gauge should peg full. In Steve's case it seems all these can be ruled out, leaving only the float arm adjustment.. @PurpleBeeper you can try the quick gauge test to make sure the gauge works, and then temporarily run a piece of wire from your gauge wire under the dash down to your sending unit(bypassing the existing wire)...to rule out high resistance in the wire, especially if it's old
Click to expand...

THANKS BEAN! I do have original body wiring & I didn't think of that. I will try running a wire from sender as close as I can to the gauge (at some convenient connector) and see if the gauge moves up higher than 1/2-way. GREAT IDEA
 
I had to actually break my sender arm off the unit, re-weld back on, and then twist it around until it read correctly at empty. Now it reads normal as it gets towards empty but still goes way past full when full..... What a joke these senders are. One can only dick with these things for so long....it gets old. Thanks aftermarket dumbasses.
 
Roadcuda said:
This is what I used on my Road Runner. It was easy to install, and has good instructions.

http://technoversions.com/MeterMatchHome.html
Click to expand...

I bought the same thing and had inconsistent readings. First, you need an electronic dash voltage regulator. The points style on off on off messes the readings up. But even with an electronic vr installed, my fuel level was inconsistent after setting the values and it wonked up my temp gauge.

I ended up bending the arm to read full when full and empty when empty.
 
I did two things to resolve this on the 68 GTX.

1. With the sender out, connect a jumper to ground and hook up the gauge lead. Move the sending unit float arm slowly through the range and confirm the gauge works through the entire movement. This is a lot easier than resistors and all that stuff. Also assumes you bench tested it with an ohm meter first to make sure it's in spec.

2 . Tweak the arm. All I did was eyeball the arm from where it should empty to full and bent it a little. The arm was low, it sat below the fuel sock when at the bottom part of the throw. It doesn't take a lot.

This worked really good. One thing is the aftermarket senders have too much throw for the tank meaning it'll never be over full or over empty depending on how you bend the float arm.
 
I've been dealing with this. Any new repro sender is foreign made junk. I've sent 2 back. The Chinese senders are not made to read properly as the original factory senders did. They absolutely will never read full or correctly through the range. We need to not put up with that junk otherwise companies will keep shoving it off on us. I've heard the Canadian made senders (spectra) work as the originals did but I've never tried one. I've resorted to soaking my original sender in a tub of evaporust and installing a new float and sock
 
400sforever said:
I've been dealing with this. Any new repro sender is foreign made junk. I've sent 2 back. The Chinese senders are not made to read properly as the original factory senders did. They absolutely will never read full or correctly through the range. We need to not put up with that junk otherwise companies will keep shoving it off on us. I've heard the Canadian made senders (spectra) work as the originals did but I've never tried one. I've resorted to soaking my original sender in a tub of evaporust and installing a new float and sock
Click to expand...
I have yet to see a new one work properly....Spectra included....Ohms read within range and wallah not even close....

Reproduction junk...
 
on second thought, i'll leave well enuff alone, and watch the miles
 
I have had the gauge read low and not register full when the tank is full. I had check everything and no change. New rebuilt sending unit. I finally went under the dash and first loosened the nuts that hold the gauge to the circuit board then cleaned the contact area and re tightened the nuts and I had a correct reading gauge. Maybe I was lucky but I have a working gauge.
 
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