FUEL GUAGE PROBLEM

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sgrip65

sgrip65

66 Dart GT 273, 65 Dart GT 273 HiPo
FABO Gold Member
Joined
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Hello Members. On my fuel guage 1966 Dart. The guage needle, in the car, goes from below empty to the empty bar on the guage, then stops. Following is what I have done.

1. New Dashboard Printed Circuit Board
2. New IVR4
3. New fuel sending unit.

1. Using the fuel sending unit outside of the car, with proper ground, and manually moving the float,
the dash fuel gauge shows empty to full as it should. This test was done both at the toe kick junction
and at the fuel tank sending unit.

2. The blue wire from the toe kick junction to the fuel tank sending unit ohms out showing no short to ground.

3. The IVR4 is new and the voltage shows as it should.

4. The Printed Circuit Board is new.

5. With the tank out of the car with the fuel sending unit installed along with a jumper ground attached and the. blue wire attached with a jumper wire to the fuel sending unit, I added water to the tank. With the water rising. in the tank, the fuel gauge guage rose from empty to full as it should.

6. I, then, emptied the water, dried the tank, and installed the tank with the fuel sending unit installed. I double checked for power at the fuel sending unit, checked for grounding, added an auxilliray ground, and added fuel. The 66 Dart has a fuel tank capacity of 18 gallons. I added eight gallons of fuel, and the fuel guage rose to the empty bar and stopped.

I do not know what else I can do to resolve the problem. Any other thoughts on this would be appreciated.
Thanks. Sgrip65
 
Hello OM MOPAR. I will give that a try. Thanks. Sgrip65
 
Oldmanmopar said:
Ground the wire at the tank and see if it goes to full. You'll need two people. If it does your problem at the tank.
Click to expand...
Hello Oldman Mopar. I did jump the ground to the fuel sending stud. As you described, the dash fuel guage went to full. So, the problem is at the tank. New tank, or different/new sending unit?
Thanks again. Jerry (sgrip65)
 
sgrip65 said:
Hello Oldman Mopar. I did jump the ground to the fuel sending stud. As you described, the dash fuel guage went to full. So, the problem is at the tank. New tank, or different/new sending unit?
Thanks again. Jerry (sgrip65)
Click to expand...

I have had brand new sending units fail straight out of the box before. Since then I've started using Kramer sending units and haven't had an issue since. According to them, they test each one before it gets boxed.

I've also used Vans' sending units as well and have had good luck.
 
Just Send It said:
I have had brand new sending units fail straight out of the box before. Since then I've started using Kramer sending units and haven't had an issue since. According to them, they test each one before it gets boxed.

I've also used Vans' sending units as well and have had.
Click to expand...

Hello Just Send It. Thank you for the input. Hope to get this resolved. I will update the results. Appreciated. Sgrip65
 
The one thing you have not done is check accuracy. You may have already done so, but you also MUST make certain of electrical integrity.

Keep in mind ALWAYS that "new" parts do NOT mean "properly working" parts.

You've already done some good stuff here, now check the accuracy. The factory had gauge check boxes, that were simply a switch and 3 resistors. The photo is not a factory box, but an aftermarket dupe:

c-3826-jpg.jpg


So now, temporarily disconnect your fuel sender and lay it where it will be stable. Adjust the sender with an ohmeter for 74 ohms. Connect the sender to the gauge, set up battery and ground input (don't forget to ground both the sender AND the cluster!!) and the gauge should read as described on the box. Do the same at 23 ohms (1/2 full) and with 10 ohms (full mark to +3/32 of it)

Also do a search on here. There are many threads detailing that mondern tank replacment senders are simply not accurate. They are not made correctly

There exists a couple of brands of gauge corrector systems, one of which is known as "meter match." This is a little box, about ?? 70 bucks ?? or so, that goes in the circuit and can be programmed to correct readings with an otherwise working system.

This is the cheaper corrector that has shown up, I know nothing of their reliability

ALSO READ THIS THREAD!!

www.forabodiesonly.com

Another gauge corrector--cheaper than MeterMatch, 33.00

I don't know anything about them. Says "Dolphin", seller is "oldnewparts" Fuel Sender To Gauge Converter Module Ohm Adjust To any Sender To Gauge | eBay
www.forabodiesonly.com www.forabodiesonly.com

AND ANOTHER which talks about "meter match"
www.forabodiesonly.com

Fuel Gauge Sending Units compared

I posted this on slantsix.org but I thought I should share it here too. There have been several threads here about the aftermarket sending units not working quite right with the factory gauge. In particular, it reads full when full, empty when empty, but at mid-ranges the aftermarket unit...
www.forabodiesonly.com www.forabodiesonly.com
 
Last edited:
67Dart273 said:
The one thing you have not done is check accuracy. You may have already done so, but you also MUST make certain of electrical integrity.

Keep in mind ALWAYS that "new" parts do NOT mean "properly working" parts.

You've already done some good stuff here, now check the accuracy. The factory had gauge check boxes, that were simply a switch and 3 resistors. The photo is not a factory box, but an aftermarket dupe:

View attachment 1716107086

So now, temporarily disconnect your fuel sender and lay it where it will be stable. Adjust the sender with an ohmeter for 74 ohms. Connect the sender to the gauge, set up battery and ground input (don't forget to ground both the sender AND the cluster!!) and the gauge should read as described on the box. Do the same at 23 ohms (1/2 full) and with 10 ohms (full mark to +3/32 of it)

Also do a search on here. There are many threads detailing that mondern tank replacment senders are simply not accurate. They are not made correctly

There exists a couple of brands of gauge corrector systems, one of which is known as "meter match." This is a little box, about ?? 70 bucks ?? or so, that goes in the circuit and can be programmed to correct readings with an otherwise working system.

This is the cheaper corrector that has shown up, I know nothing of their reliability

ALSO READ THIS THREAD!!

[/URL]

AND ANOTHER which talks about "meter match"
[/URL]
Click to expand...

Hello 67. Good stuff in your reply. Thank you. Looks like I will have something to do today. Appreciated. I will check the attached threads. Sgrip65.
 
Sometimes the tank itself doesn't ground well, that is why the factory added a ground strap on the fuel line itself bridging the rubber line. Is yours missing?
 
Hello Murray, The pronged ground strap from the tank to the metal fuel line jumping the rubber fuel line at the tank to fuel line is installed. As well, I placed an auxilliray ground jumping the rubber connection at the tank to fuel line connection. Great suggestion though. Thank you for your input. Appreciated. Sgrip65
 
This is frustrating. Another idea- what material is the float made of? Brass? Can the float have a small leak (they usually are) and filling with gas? I think gas will seep into areas that water can't. I would sink the float in a can of gas to test this.
 
Murray said:
This is frustrating. Another idea- what material is the float made of? Brass? Can the float have a small leak (they usually are) and filling with gas? I think gas will seep into areas that water can't. I would sink the float in a can of gas to test this.
Click to expand...
Hello Murray. The float is plastic on the new fuel sending unit. The old one, the one I took out, had a brass float. Neither had holes or fuel within the float that I could determine by shaking it, the float. Great recommendation, as we can mark each, as we go, as not being the issue. Always Flow Chart it I have been taught!! It will get figured out as there is a great deal of mopar talent on FABO. Hopefully, it's something quite simple that is staring right at us. To be honest, as Just Send It suggested that the "NEW" sending unit DOES NOT MEAN it works/Functions as it should. I am going to sink the sending unit in a pan of gas and see what happens as you suggeted. Stay tuned, as I am challenged by this, and most learn from such a frustration. Thank you for your input and help on this. Appreciated. Sgrip65
 
The struggle is real and i feel your pain, I have 2 cars a 68 Roadrunner and a 73 Duster and both gauges were off by 50% or so. both have new tanks, senders and PC boards in the dash with solid state regulators. Both senders a Right stuff Detailing from Summit IIRC. What I did was to drop the tank and pull the sender. I set the tank on a cart to approximate the same level as in the car, My lift made it easier. Then I jumper wired every thing with a good ground of course. Then I pull the sender out and bent the arm ever so slightly and reinstall it on the cart. Had to fiddle with it about 4-5 times to get what I approximated was 1/2 tank of fuel. I am happy with the outcome and have not had to guess at the level anymore. Before, reading empty it would only take 9-10 gallons on a 19 gallon tank on the 68. Those ground Jumpers are made of the same Junk as the sender sealing rings. I did the same as you did for the ground strap. Kudos to that. This has been an issue with repop senders forever.
 
george joseph reid said:
The struggle is real and i feel your pain, I have 2 cars a 68 Roadrunner and a 73 Duster and both gauges were off by 50% or so. both have new tanks, senders and PC boards in the dash with solid state regulators. Both senders a Right stuff Detailing from Summit IIRC. What I did was to drop the tank and pull the sender. I set the tank on a cart to approximate the same level as in the car, My lift made it easier. Then I jumper wired every thing with a good ground of course. Then I pull the sender out and bent the arm ever so slightly and reinstall it on the cart. Had to fiddle with it about 4-5 times to get what I approximated was 1/2 tank of fuel. I am happy with the outcome and have not had to guess at the level anymore. Before, reading empty it would only take 9-10 gallons on a 19 gallon tank on the 68. Those ground Jumpers are made of the same Junk as the sender sealing rings. I did the same as you did for the ground strap. Kudos to that. This has been an issue with repop senders forever.
Click to expand...
Hi George. Bending the float arm...genius move. Guess I never thought about that, and I consider myself reasonably handy....most of the time. Thanks, I learned something today. I will post the remedy at the time I get this dilemma fixed up. Appreciated. Sgrip65
 
Oldmanmopar said:
Ground the wire at the tank and see if it goes to full. You'll need two people. If it does your problem at the tank.
Click to expand...
I did this test I have no voltage on my blue wire at the tank so I grounded and still our gauge in my dash reads empty . I can't find if the blue wire should have voltage or not
 
george joseph reid said:
The struggle is real and i feel your pain, I have 2 cars a 68 Roadrunner and a 73 Duster and both gauges were off by 50% or so. both have new tanks, senders and PC boards in the dash with solid state regulators. Both senders a Right stuff Detailing from Summit IIRC. What I did was to drop the tank and pull the sender. I set the tank on a cart to approximate the same level as in the car, My lift made it easier. Then I jumper wired every thing with a good ground of course. Then I pull the sender out and bent the arm ever so slightly and reinstall it on the cart. Had to fiddle with it about 4-5 times to get what I approximated was 1/2 tank of fuel. I am happy with the outcome and have not had to guess at the level anymore. Before, reading empty it would only take 9-10 gallons on a 19 gallon tank on the 68. Those ground Jumpers are made of the same Junk as the sender sealing rings. I did the same as you did for the ground strap. Kudos to that. This has been an issue with repop senders forever.
Click to expand...
I ran a ground from sending unit to a good ground on the car about 10" from sending unit and it's s good ground . I don't have voltage on my blue wire at the tank . I can't find in any post if there is supposed to be or what it should measure
 
Thanks FABO for the tips on solving this gas guage problem. I found that, just because the sending unit is new, does not mean it works. A new tank, another new sending unit, replaced the fuel gauge again, and all new wiring. I am not sure which it was, but it works now as it should. Glad of it too.
Sgrip65
 
Anyone know if that blue wire should have voltage ? If yes what voltage should it have ? I don't want to put 12vdc to it as 12vdc to dead ground with tank full of gas seems like bad mix
 
There should be voltage at all sender wires. OEM mechanical regulator produced a pulse voltage through the gauge windings to fuel and temp senders. Oil sender also if there is an oil gauge. That would show 2.X to 3.x VDC on analog meter that averaged about 5 volts. A digital meter wont show more than rapidly changing numbers. "IVR4" suggests aftermarket solid state regulator. That is said to send increased voltage at switch on then settle back to a steady 5 VDC as needle reaches where it was headed.
 
I seem to have a situation with my fuel gauge that MIGHT be similar to sgrip65 . I’ve pulled the instrument cluster and purchased a device that allows me to dial in resistance. With a good voltage limiter (old and new limiters provide a good 5 volt pulse) - I found that the gauge reads full at 3 ohms, 1/2 full at 11 ohms, and empty at 38 ohms. My sender is out of this loop (still installed) and it has its own problems. 1). Anyone know of sgrip65 solved his problem? 2) Any chance that a gauge corrector system would help me in this case?
 
I probably should have added that I’m dealing with a 71 Duster and I know its maintenance history since I’m the original owner.
 
Ken71Twister said:
I seem to have a situation with my fuel gauge that MIGHT be similar to sgrip65 . I’ve pulled the instrument cluster and purchased a device that allows me to dial in resistance. With a good voltage limiter (old and new limiters provide a good 5 volt pulse) - I found that the gauge reads full at 3 ohms, 1/2 full at 11 ohms, and empty at 38 ohms. My sender is out of this loop (still installed) and it has its own problems. 1). Anyone know of sgrip65 solved his problem? 2) Any chance that a gauge corrector system would help me in this case?
Click to expand...
There started out being "1" then now there are at least three of these gauge correctors on the market. But first, the system has to work "somewhat." "Metermatch" was the original
 
Ken71Twister said:
I seem to have a situation with my fuel gauge that MIGHT be similar to sgrip65 . I’ve pulled the instrument cluster and purchased a device that allows me to dial in resistance. With a good voltage limiter (old and new limiters provide a good 5 volt pulse) - I found that the gauge reads full at 3 ohms, 1/2 full at 11 ohms, and empty at 38 ohms. My sender is out of this loop (still installed) and it has its own problems. 1). Anyone know of sgrip65 solved his problem? 2) Any chance that a gauge corrector system would help me in this case?
Click to expand...
Hi Ken71. I was absolutely lost on this with my fuel gauge problem. I wound up buying a new tank (the old one was dented up.) As well, a new sending unit, I had a different gauge which I installed. I tested, by hand, the new sending unit at the toe kick, and it seemed to work well. However, when I installed the new sending unit, I added exactly 1/2 a tank of fuel, and the gauge went to 1/4 tank. Then I filled the tank completely, and it went to 1/2 full on the guage. I did not test the ohm resistance reading. Anyway, I had the 5 Volt pulse, and, now, the gauge reads at1/2 full when full. There is not any fuel within the float causing the float arm to sink, I have the 5 Volt pulse, the gauge was tested using the sending unit at varied positions outside of the car, the wires have been tested to be sure that there are no shorts to ground, and the PCB (printed circuit board) was tested with no opens or shorts. Anyway, that is where I am at. It was suggested using a meter match device. Looks like this will be a next winter job. What is odd is that, outside of the tank, using manual movements of the sending unit float's arm, the gauge reads empty to full with that movement; however, installed, no. I have been told that these sending units are notorious for false readings. I will live with this till next Winter. Sorry I could not be of more help. Thanks for the inquiry. Sgrip65
 
Thanks to both of you for the responses. Your gauge reading full with manual (out of tank) sending unit operation makes me wonder if the sending unit is designed for a tank with more height. If that’s the case - the sending unit arm might not be able to raise high enough to use its full range. That’s a caution to me to learn more about sending gauges if/when I need to buy a new one.
 
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