Look to find an NOS unit OR a nonfunctional OE unit that you can have repaired.
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Gas gauge problems
- Thread starter plymouth71
- Start date
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plymouth71
The Moomobile
That helps a lot,I would have never figured there was so much to troubleshooting a nonfunctional gauge,thanks
plymouth71
The Moomobile
I'll start looking,thanks
plymouth71
The Moomobile
I'll start looking,thanks
tell me about it. As you can see from the chart I added and removed one gallon at a time to create the resistance charts.
Frnknsteen
Well-Known Member
One other thing. When you remove your sender, make sure the float isn't full of gas. Could just be a bad float that is sinking in the fuel. When you remove the sender, ground the body of it to chassis and move the float arm up and down. If the gauge reacts, the sender is good and it may just be the float leaked and filled with gas.
My fuel gauge isn't working on my '71 Chev C10. I just pulled it out this past weekend and found that the sender works fine when you move the arm, the float just had a crack in it and filled with gas. Ordered a new float and it's good to go.
My fuel gauge isn't working on my '71 Chev C10. I just pulled it out this past weekend and found that the sender works fine when you move the arm, the float just had a crack in it and filled with gas. Ordered a new float and it's good to go.
Frnknsteen
Well-Known Member
Curious,... How do the bends on the float arm and the position of the sweeper box compare between the OE and the aftermarket? I'm wondering if there is a slight difference in the float location on the arm, relative to the sender body and pickup tube, and if that has something to do with the difference in the profiles as you fill it.
I'm thinking if the float is pointed down more at the bottom of the stroke, it is going to move the arm more at the bottom than the aftermarket one if the float arm has a lesser angle. Once you get some fuel in there, and the arm starts to get at an angle, it would move less for a given rise in fuel. Don't know if I am explaining what I am thinking correctly.
Reason I say that is the OE reacts once 2 gallons have been added, while the aftermarket doesn't react until 4 gallons have been added. That tells me the OE float sits lower in the tank. If the windings in the sweeper spring are consistent, it should be linear, but it isn't. That's why I'm wondering if the bends in the float arm are different, causing it to move different amounts as the fuel level rises.
Just a thought,... sorry,... didn't mean to get side tracked.
I saw a photo of a confirmed NOS 67 and the tube layout and the location of the reostat and the length of the arm the float is on are very different from my later production NOS and the aftermarket ones. I agree that all you mentioned will effect the graph now let me toss in one more for you...
The shape of the tank. If it were a pure rectangle one gallon added would raise the fuel level (just for example but not in reality) 1 inch the next gallon another 1 inch etc. but a-body tanks are tapered on the bottom so the fuel level will rise at a non linear rate till the level is above the tapered area, then it will raise lineally till it hits the carved out area for the spare tire.
I have seen the winding on aftermarket senders and they do seem to have the same number of winding per inch throughout the entire range and on at least one OE sender they were not.
ALSO (but I don't know this for sure) the gauge might have its own non linearity. I was building a resister box to prove that out but haven't finished it yet.
Frnknsteen
Well-Known Member
I agree completely,... the shape of the tank will affect linearity, but in your case, I assumed you were testing both senders in the same tank, so the tank shape would be removed from the equation. Interesting that the length of arm and rheostat location were different. You'd think that would be an easy thing for them to duplicate. Also find it interesting that the windings were not consistent on the OE sender.
I agree with you that the gauge itself is not necessarily linear. At least on the rally gauge set I rebuilt, the resistance range was 10ohms to 75 ohms, with about 23 ohms putting the needle in the middle of the gauge. If they were linear, the midpoint should be 32.5 ohms
jedrattle
Well-Known Member
What companies do this repair?
67Dart273
Well-Known Member
Did you generate this yourself, or where did you get this?
ALSO TO OP: REpop senders have a VERY bad reputation for accuraccy. For about 50 bucks, there is a little add-on box you can buy which can be used to accurize your gauge readings "Meter Match"
TechnoVersions - MeterMatch for Analog Gauge Correction
I would NOT play with this until you get the system working or replace sender and do so........
Yes one gallon at a time!
Yes same tank but if the OE sender is "calibrated" to the tank or the gauge or both I suspect that is why you see the difference in profiles on the graph.
furyus2
Well-Known Member
This is interesting. Better than trying to find an original sender.
famous bob
mopar misfit
Having replaced all fuel related pieces in my 68 fastback, and the dam gauge still aint right, it makes me want to go to a 20gal fuel cell !
Wagon of Death
Aussie Barracuda Fisherman
Im right there with ya Bob...Im gonna give this one more try and then its fuel cell time...Im over guessing
Pawned
N.R.A. Lifetime Member - And damn proud of it
I have been fighting this from 10 different ways, for the last 5 years. I have almost given up on getting the gas gauge to work. There have been numerous threads on this subject and 100s of people that know it all, have given advice to NO END.
I will keep playing with this on my free time, but do not see a positive end to this problem
I will keep playing with this on my free time, but do not see a positive end to this problem
Frnknsteen
Well-Known Member
There really isn't much to it. I see a ton of people having issues with their fuel senders, and I guess I don't see why. There isn't much to the system. As long as you are getting the proper voltage to the gauge (That is an issue for many). I bought a variable DC power supply that I can calibrate with my volt meter to test the gauge itself (using a variety of resistors). Then confirm the sender is properly grounded. After that, it all comes down to resistance of the sweeper on the fuel level arm.
Don't get me wrong,... if the aftermarket ones have the wrong resistance range,... that is going to mess with you! I had to add a 10ohm resistor to my temp gauge in my Chev C10 because the resistance of the sender was off when at normal operating temp. I confirmed temp with a calibrated IR thermometer, then added the extra resistor. Needle runs right where it should now. If I see it spike up or down, I will know I have a problem.
I don't worry too much about accuracy of the fuel gauge as I consider it a reference only. Except at the bottom. I need to know when I am going to run out. I don't know about other models, but on my Charger gauge, you can adjust the needles. I set mine so 75 ohms sets me just below empty. I will tweak it a bit once I get everything installed and see what the resistance of the sender is with the float arm all the way down.
Don't get me wrong,... if the aftermarket ones have the wrong resistance range,... that is going to mess with you! I had to add a 10ohm resistor to my temp gauge in my Chev C10 because the resistance of the sender was off when at normal operating temp. I confirmed temp with a calibrated IR thermometer, then added the extra resistor. Needle runs right where it should now. If I see it spike up or down, I will know I have a problem.
I don't worry too much about accuracy of the fuel gauge as I consider it a reference only. Except at the bottom. I need to know when I am going to run out. I don't know about other models, but on my Charger gauge, you can adjust the needles. I set mine so 75 ohms sets me just below empty. I will tweak it a bit once I get everything installed and see what the resistance of the sender is with the float arm all the way down.
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