• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Fuel Tank Sending Unit Question

As everyone has stated, none of the reproductions currently available are accurate. Testing the units to observe that the desired levels of Ohm resistance does not give a factual reading of the unit at various levels of fuel.

Some of the units are so poor that the plating will begin to rust immediately after installing them into a tank. The Spectra units seem to hold up although they are not accurate.

Seeing that you are replacing the tank, make sure that the sending unit lock ring is the correct thickness. There are numerous threads out there concerning the new lock rings furnished with the new tanks that are not thick enough. Reuse the original lock ring or purchase a new one from a reputable vendor who sells one of the correct thickness material.

Personally, if I was replacing a tank, I would replace the filler tube grommet; reuse the sending unit if operable, just replace the sock; reuse the lock ring and replace the fuel tank studs and nuts and all of the rubber lines.
I would add, perform a leak test on the float, too.
 
I just recently replaced my gas tank in my charger, and tested it before i put it in, after getting the tank back in and strapped up, doesn't work anymore, wish i would've just changed it out while i had it all down. Just my input.
 
my original one just died, period. So went thru 3 repro units from various suppliers, all junk either resistance was way off or simply could not adjust them enough to make them correct. Last one I ordered I got from Van's Auto. Do not who makes them, but this one was perfect out of the box and works wonderfully, no adjustments required. Worth looking there I guess, I would.
 
my original one just died, period. So went thru 3 repro units from various suppliers, all junk either resistance was way off or simply could not adjust them enough to make them correct. Last one I ordered I got from Van's Auto. Do not who makes them, but this one was perfect out of the box and works wonderfully, no adjustments required. Worth looking there I guess, I would.
Thanks, I just ordered one.
 
TriStarr Radiator ( I hope I got that correct) rebuilds fuel sending units. They did a nice job on mine.
 
I'm with the "if it's not broke don't fix it", but there is a lot you can compare between the new one and the original. Get a ohmmeter and compare total resistance between the two and the difference in resistance at the different angles of the arm. Also compare the shape of the two to make sure they are actually shaped the same. My original in my 70 Bird was not able to be saved therefore I have spent endless hours trying to make the new one accurate. The best I have been able to do is get it where I have about a gallon left when it shows E, and when the tank is completely full the gauge shows about a needle width below F. If I make it show F it will run out of gas before E. The cluster was professionally done and calibrated by Redline Gauges and there is nothing wrong there.
I would be happy with your results. What did you have to do to get it to work as it does now? ..................MO
 
I would be happy with your results. What did you have to do to get it to work as it does now? ..................MO
With the tank out and the filler neck removed, I installed the new sender, after comparing the resistance which liked 5 ohms of being what the FSM said it was supposed to be. I used some long enough wires to obtain a ground and the sender wire attached to the sender. I put 1 gallon of gas into the tank with the tank adjusted to the angle it was in the car. Then went to the car and checked the gauge. I had to remove the sender about 5 times and bend the float before I got it to read E. I then installed everything in the car. What I got on the full side was what it was. I am assuming that the 5 ohms may have taken it to F. There is no way that I could find to add that resistance.
 
I would be happy with your results. What did you have to do to get it to work as it does now? ..................MO
With the tank out and the filler neck removed, I installed the new sender, after comparing the resistance which liked 5 ohms of being what the FSM said it was supposed to be. I used some long enough wires to obtain a ground and the sender wire attached to the sender. I put 1 gallon of gas into the tank with the tank adjusted to the angle it was in the car. Then went to the car and checked the gauge. I had to remove the sender about 5 times and bend the float before I got it to read E. I then installed everything in the car. What I got on the full side was what it was. I am assuming that the 5 ohms may have taken it to F. There is no way that I could find to add that resistance.
With the sender installed, could you look in the filler neck and see where the pick up tube was in relation to the bottom of the tank? I have heard that the pick up tube may have to be bent to get it down near the bottom of the tank.............MO
 
Should I use my original sending unit in new gas tank or replace it with a new one. Some say the new units won't read correctly?? I have a new one purchased from Spectra, but still have my original also.
I had the unfortunate luck to have a non-working gas gage. A buddy of mine replaced the tank, sending unit and installed an under-dash gage. This worked well except the tank was full when the gage read 3/4.
So calibrating it again was not an option. So where was empty? Did not find out.
 
With the sender installed, could you look in the filler neck and see where the pick up tube was in relation to the bottom of the tank? I have heard that the pick up tube may have to be bent to get it down near the bottom of the tank.............MO
Definitely and I don't know why everyone (other than those with a Charger) don't do it to make sure things are sitting correctly, both the intake tube/filter sock and the rheostat.
beerestoration2018 174.JPG
 
Definitely and I don't know why everyone (other than those with a Charger) don't do it to make sure things are sitting correctly, both the intake tube/filter sock and the rheostat.
View attachment 861942
I did that since I have a handy dandy inspection camera. First, I took ohm readings to make sure the sender was good and it was. I still get inaccurate readings with fuel in the tank. So, I just fill up every 150 miles or so.
 
You can shine a mag light in there, even with the filler neck in place, and see the float and pickup tube with your eyes. VERY easy to install it sitting crooked.. after smacking the lock ring tight. I took this picture with my pocket camera.
 
Definitely and I don't know why everyone (other than those with a Charger) don't do it to make sure things are sitting correctly, both the intake tube/filter sock and the rheostat.
View attachment 861942
Is this pic , showing the position of components , with everything adjusted to where the guage showed just a bit under full with a full tank, and about one gallon left when needle was on empty? You have provided some great info---Thanks.........................MO
 
Ordered a new one through Summit and tested it this afternoon....77 ohms empty, 8 ohms full. The sending unit was something like $39 and had good reviews....time will tell if it's good or not.

The FULL and EMPTY readings are not hard to duplicate by the aftermarket builders. Where they fall short is the way it reads in between full and empty. The aftermarket sending units supposedly read in a linear manner. The original versions did not. This means the new senders read fine if you just filled up or just ran out of gas but are not accurate in between!
 
VERY easy to install it sitting crooked.. after smacking the lock ring tight. I took this picture with my pocket camera.
You have to get yourself one of these tools Wayne. So much easier to get things lined up and straight.

20191108_060554.jpg
 
Auto Transport Service
Back
Top