The 18 gallon plastic gas tank in my 75 D-100 had a hairline crack/leak and the gauge was reading inaccurately (only read from 3/8 of a tank down to empty) when tank was almost full , so I decided to drop the tank. I patched the crack and installed a new sending unit. Replaced all the rubber lines and put it all back together. I put 5 gallons of gas in and started it up. It ran perfectly until it burned all the fuel in the gas line then it quit. Now its not getting any gas and I cannot figure out why. All the lines are hooked up correctly same way as before. I have checked this multiple times and see no kinks in the lines or any other reason for gas not to come through. When I pour gas in the carb it fires right up. So its definitely not getting fuel through the fuel line. The gas gauge needle barely moves at all as well.

What could be keeping me from getting gas and why is the gauge still not reading right? What could I be missing here? I should have known this would not be so easy as to just start working good on the first try!!

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

Faulty sending unit (cracked or blocked fuel pickup pipe), fuel strainer not properly installed on the fuel pickup pipe.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks for the reply Dan. I'd say its a good possibility on the sender being faulty, it's a remanufactured unit. I really did'nt want to go with a reman but I could not find a Mopar original. I'm going to pull it all back out and check.

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

Any air leak thru a crack or "pin-hole" will make it hard to suck fuel thru the line so look closely for any way air can get into the line.
DD

Ok, pulled everything back out and did following:

!. Blew out all the lines with compressed air to make sure no blockage and all was clear.
2. Verified fuel pump was pulling by cranking engine with fuel line off.
3. Hooked up sender to wires with tank removed and verified it was working with the gauge. I then calibrated the two by adjusting the stop tabs on the float arm with the full mark on gauge.

buttoned it all back up, put about 3 more gallons of gas in than the first time and it cranked right up. Now the fuel gauge is not reading again!!! What could be keeping this gauge from working with tank installed? Am i losing ground from rubber gasket under the sender or could I have gotten the arm caught under the lower float stop when i put the sender back in the tank??

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

The round portion and tap or stub flexible fuel line attaches to has to have a good ground. This is accomplished with a factory metal strap bridging flexible cupping between steal fuel line and sending unit which attaches to sending unit's tap, and metal fuel line to provide a ground path.

If your factory ground strap is not making a good electrical connection, than fashion a jumper using a length of wire attached by small hose clamps.

Sometimes steel fuel line's attachment clips will loose enough conductivity from corrosion it no longer can function as a grounding point. In such a case attach a wire to sending unit tap, and ground to frame member via a screw & eye.

A quick test for bad ground: Attach a jumper to sending unit tap, and ground jumper to a known good grounding point, and see if gage moves.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

My truck has the factory original grounding wire that attaches to frame cross member with an eye and bolt on one end. The other end attaches to the top of the sending unit with a boot that slides over the stud connector. This wire is in good condition and is securely in place. One would think it would give sufficient ground, in which it does perfectly when sending unit is connected to both wires and "hanging" outside the plastic tank. Needle moves great and reads accurately with float arm positioning.

But when sender and tank are reinstalled together, the highest the gauge will go is the 1/4 tank mark. The gauge will move from empty mark up to about the 1/4 tank mark as the tank is filled from 1/2 tank up to being completely full. What in the world could be making this gauge act like this when it is all put back together?? The fact that everything works perfect when sender is out of tank means to me that the gauge and sender are good. So is it in the wiring? What is making the difference here?

I ran another ground wire from the sender ground stud directly over to the frame and it yielded no results. I have the frame grounded really well on this truck so I thought that might do the trick but it didn't. Wjajr, are you saying I should try running a ground from the sender and "bridge over" the rubber lines to the steel lines as a way of tying the sender to the steel lines together? Thanks for the help on this!!

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil

I didn't go back and read your first post explaining the vehicle is a truck, and my memory seams to be located in some black hole in another town these days...

A Body cars use a steel jumper or strap to ground sending unit to steel fuel line. It is the first suspect if fuel gage is not working; or rather a bad ground.

You may have a different problem, either resistance coil does not posses the same parameters (about 10 ohms to 78 ohms) as the factory unit which will cause a factory gage to give false reading, or the float is experiencing restricted articulation in some way within the tank, and not able to fully swing to register full.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks Wjajr, for making me think about the interior positioning of the sender. When I installed the unit, I became more focused on getting the holes for the screws to line up more than the movement of the float arm within the interior of the tank. It sounds weird but even though those screw holes in the top of the sender appear to be uniform, they didn't want to line up in whatever position I "clocked" the sender.

Well I'll have to burn off some fuel now for about a week and pull it back out and see if that's the problem. The good news is, it's not gonna take me very long as much practice as I've had pulling it in and out!!

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1975 Dodge D100 2wd Reg.cab 225/6, 727auto, 3.55 gears, Cat delete with 2.25" Thrush Exhaust, Dist recurve by DI, 9.1 comp, Factory aluminum 1bbl intake with heatshield, 63 Jet, Delete ballast with Pertronix Flame Thrower 3ohm coil