Am I Missing a Grounding Strap For My Gas Tank Sending Unit?

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Duster256

Duster256

Honolulu, Hawaii
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I recently pulled both rear tires/wheels to take a peek at what kind of rear shock absorbers were on the car. I noticed that the previous owner installed air shocks and had zip-tied the air supply line T-fitting to the blue wire for the gas tank sending unit. See the 4 attached photos. Notice in the first pic that the fitting on the air shock closest to the camera (upper left corner of the pic) doesn't have a supply line attached to it.

Two questions for FABO Nation:
  • I believe my car is missing a grounding strap for the gas gauge sending unit?
  • A missing grounding strap could cause or contribute to my inaccurate gas gauge readings (the infamous 9-gallon fillup)?
Thanks, Dave

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Probably getting a good ground right off the tank straps, but yes you're missing the factory ground strap.
 
dadsbee said:
Probably getting a good ground right off the tank straps, but yes you're missing the factory ground strap.
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The strap grounds the tank but with an o ring seal for the sender, the sender to chassis or fuel line ground is sketchy.
 
toolmanmike said:
The strap grounds the tank but with an o ring seal for the sender, the sender to chassis or fuel line ground is sketchy.
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The lock ring grounds the sender to the tank just fine, the O ring is between the tank and the inner sender face.
 
dadsbee said:
The lock ring grounds the sender to the tank just fine, the O ring is between the tank and the inner sender face.
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For clean, non-rusty parts, agreed. The factory used a clip on ground strap spanning the rubber hose section from sender pipe to fuel hard line for a reason though. If it wasn't necessary, they would have for sure decided to save a few cents on every car and done away with them.
 
cudamark said:
For clean, non-rusty parts, agreed. The factory used a clip on ground strap spanning the rubber hose section from sender pipe to fuel hard line for a reason though. If it wasn't necessary, they would have for sure decided to save a few cents on every car and done away with them.
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Guess you missed post #5.... I do know what is proper..
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cudamark said:
For clean, non-rusty parts, agreed. The factory used a clip on ground strap spanning the rubber hose section from sender pipe to fuel hard line for a reason though. If it wasn't necessary, they would have for sure decided to save a few cents on every car and done away with them.
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I get the logic there but I don't really see why it's necessary.
 
you can just use a piece of wire from the sending unit outlet to any good ground, like a ring terminal on the wire screwed to the frame somewhere convenient.
 
RustyRatRod said:
If somebody doesn't think you know what proper is, they ain't been readin your threads. lol
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LOL, and here's a better way than factory, as factory correct = expecting a body ground from a grungy fuel line, one bolt on tube clamp and some clip on tube holders to do a good job.
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Yes you are missing the ground strap.
And I will add this:
If your fuel gauge isn't working, many times (missing ground strap) is the reason.
 
I'm guessing it probably has something to do with static buildup control. If you're pumping the fluid from metal through a rubber hose to more metal, maybe they were protecting against some kind of static buildup? Probably rare and plenty of places for it to dissipate, but cheap insurance.
 
Map63Vette said:
I'm guessing it probably has something to do with static buildup control. If you're pumping the fluid from metal through a rubber hose to more metal, maybe they were protecting against some kind of static buildup? Probably rare and plenty of places for it to dissipate, but cheap insurance.
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Nope......Actually it is there to complete the ground circuit between the metal sending unit and the metal fuel line, which has the rubber fuel line between the two.

Remove this strap, and your gas gauge will not operate.
 
Okaaaay . . . Looks like my post opened up a big can of worms here! Differing opinions on the necessity of a sending unit ground strap encourages meaningful discussion. I’ll install a ground strap and if my gas gauge operation improves, great, and if not, no harm no foul. Thanks everyone for chiming in! Dave
 
Duster256 said:
Okaaaay . . . Looks like my post opened up a big can of worms here! Differing opinions on the necessity of a sending unit ground strap encourages meaningful discussion. I’ll install a ground strap and if my gas gauge operation improves, great, and if not, no harm no foul. Thanks everyone for chiming in! Dave
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If you want to test it out for free, just clip a wire from the sending unit line to the fuel line and see if your gauge changes. I doubt it'll correct your 9 gallon fillup problem but adding a strap definitely won't hurt anything.

The line on your sending unit looks pretty shiny. Do you know if this is an aftermarket sending unit? They're notoriously inaccurate. They require removing and bending the arm to get accurate read outs.

My car has an original one and it stays on Full for the first 50 miles and then drops from Full to Empty over the next 25 miles and stays on Empty until it's actually empty. I don't think anything can be done about that.
 
Keep in mind, with ANY tank sending unit, especially the new crap. The only thing your really care about is.... is Empty accurate !!???
 
it's kind of hard to do this once the unit is in the tank, but you can bend the arm attached to the float to change how it reads. I purposely make mine read empty when it still has 3-4 gallons in it so that I never run out.
 
ESP47 said:
If you want to test it out for free, just clip a wire from the sending unit line to the fuel line and see if your gauge changes. I doubt it'll correct your 9 gallon fillup problem but adding a strap definitely won't hurt anything.

The line on your sending unit looks pretty shiny. Do you know if this is an aftermarket sending unit? They're notoriously inaccurate. They require removing and bending the arm to get accurate read outs.

My car has an original one and it stays on Full for the first 50 miles and then drops from Full to Empty over the next 25 miles and stays on Empty until it's actually empty. I don't think anything can be done about that.
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Tx for the tip, will give it a try. I’m the third owner so I’m unsure if the sending unit is OEM or aftermarket but others on FABO have also reported 9 gallon fill ups and possible fixes. Keeping my crossed.
 
dadsbee said:
Sorry, but it will... in most cases. Most of those bonding clips rotted off 35+ years ago.
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And most of those cars, the gas gauges don't work. I can't count the A body's I've ran into where the gas gauge didn't work, and they were missing the ground strap. By adding the ground strap, voila the fuel gauge worked.

We could go back and forth until we are blue in the face on this subject. I'm not going to do it.

The Chrysler engineer's put the ground strap on for a reason.
That's good enough for me.
 
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