Fuel Gauge and fuel sending unit

[Scooter]

Been reading about on fuel gauge and sending unit issues as my gauge has not read correctly since I bought the car. When I fill up the gauge reads full tank correctly.. but drops like a rock quickly after driving just a bit. When it reads 1/4 tank I still have about 10 gallons left. Many people seem to think the grounding as the primary culprit, about an equal amount of folks feel the repop units are just junk. Mine is a repop installed by previous owner. Had not looked up what the actual ground strap looked like but figured it would not be hard to spot. Had some time yesterday to crawl around under the car and located the body side of the grounding strap just flopping about, luckily the tank side was still loosely attached. I cannot believe some engineer 40+ years back thought this:



Was a good idea. 

Did not have time to remove the muffler heat-shield and do it up right, so I just clipped both ends on so I did not lose the strap on the street. With the fuel gauge as sensitive as I'm reading to proper ground, how the heck did this setup ever fly? I'm thinking of running a wire held in place with a small hose clamp on the tank side and attaching an eyelet lug on the other end grounded to the frame. Anyone invent a better mousetrap?

[71383bee]

I think the ground has to go to the sending unit itself. Not just the tank. The sending unit is isolated from the tank by the gasket.

The strap goes from the outlet nipple on the unit over the small piece of rubber hose to the steel hard fuel line.

To be honest I don't recall a problem with them grabbing and staying connected once they are in.  Guess that's why they stuck with that system for so long on a lot of cars.


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[RUNCHARGER]

If it reads at all then you have a ground. These repro sending units are notorious for acting like that. I've used 4 of them in the last few years and they all went to empty when the tank was half full.

[Scooter]

If it reads at all then you have a ground. These repro sending units are notorious for acting like that. I've used 4 of them in the last few years and they all went to empty when the tank was half full.

Odd.. it was reading when the strap was just flopping about, not sure where is was finding a ground? Was there anything to be done to get them to read accurately? Really bugs me to be reading 1/4 tank with 10 gallons left. Or did you just leave yours as it's not worth the time to try to tweak it in?