Alternate gas tank ground?

[hillbilly deluxe]

So my fuel gauge quit working. I did a bunch of reading and troubleshooting and determined it had no ground. Then I found the ground wire dangling.

My question is this, the ground wire appears to have originally run to the sender location. I can't reach it and have zero desire to drop the tank. I used a jumper to ground the tank to the frame to confirm my hypothesis. Would it be a good idea to put a screw through the very outer corner of the tank lip and run it to the frame?

I don't want to do anything dangerous and or stupid.

This makes the gauge work:

 

[sweetk30]

take the corner wing tab / seam and pop a self tap screw threw it AFTER the welded seam area so you don't pop a hole in the tank side. then bolt a new ground to it.

on some vehicles if you can getto it I clamp a ground wire with a eyelet end on it to the sender hard line with a hose clamp. but as you said you don't have room for this with out droping the tank.

 

[hillbilly deluxe]

Yeah that is exactly what I was getting at. That alligator clip is just on the very edge of the tank lip, probably way past anywhere that would cause a leak.

I just can't help wondering if there's any weird chance that passing any small amount of current through the gas tank is unwise.

 

[sweetk30]

sender grounds to the tank anyways up top via the lock ring and its self touching the tank body .

 

[dyeager535]

Look at it this way...fuel injected setups have 12V motors running in the gas tank all their lives.

Reason gas tanks don't normally explode under any circumstances (yes it happens, you just have to try hard) is because the air fuel ratio *inside* is WAY wrong for combustion. Which is why gas leaks are a real problem, and why peoples vehicles burn to the ground...outside the fuel tank/fuel lines, there is enough oxygen to support combustion.

As mentioned, the lock ring of the sending unit is held into the metal of the tank, so the tank is grounded that way.

 

[hillbilly deluxe]

Excellent points. It's just one of those things I get superstitious about.

I watched them try to blow up a car via the gas tank on Myth Busters and they couldn't do it. The only thing burning was the vapor at the top of the tank. I worked in the oilfield for a long time and I also understand the ratio of gasses needs to be correct for combustion. We used a sniffer that looked for LEL, or lower explosive limit, when entering hazardous environments. Then there was UEL, upper explosive limit, which the environment in the tank is definitely way above.

I saw some clamps before where you hook the wire to them then they have a bolt that clamps them onto a surface. I may look for those before popping in a screw. Either way it's gonna be nice to have a fuel gauge again!

 

[dyeager535]

If you can't clearly see it, brush off that flat lip on the tank so you can see the seam. I believe the attachment method for both halves is pretty large. For some reason I want to think that the tank is somehow spot welded together with a multitude of very tiny "spots" over a fairly wide surface (~1") that appear to look like pin-prick dimples, but do not extend right up to the edge.

If you are very near the edge you would likely be fine, but just brush off the area and see if you can find the area where the two tank halves are joined.