Hi all,
Two problems today:

1) Filled up the 70 roadrunner today for the first time since I got it. Fuel gauge moved quickly to half then crawls up to just short of 3 quarters full. The tank itself is definitely full. Is this the gauge itself or would there be some problem with the sending unit?
2) More serious issue is a gas leak. Got home from the station and a little while later noticed a puddle of gas under left rear. Moved the car to garage, leaked again. Brought the car out and put it in the carport....no leak. Must have got to its level where it wouldn't leak. Put it up on jacks and refilled the tank. So far, no leak. I can't tell from crawling underneath where the leak is. I am thinking it may be the seal, but not sure. I'm wondering why it only leaked after running. Perhaps a hose? Any ideas? It'll be a couple of days before I can get it on a hoist to have a really good look.

Marty

 

1) It sounds more like it is the sending unit than the gauge.

2) Check the fill tube and return tube for cracks. Same thing with the fuel lines. If you have to drop the tank to replace the sending unit, that would be the time to replace any of these other parts if they look "not up to par".

 

Yes, the first problem is probably the sending unit. My buddies 68 Barracuda does the same thing.
The second problem I think I have narrowed down, but I won't know for sure until tomorrow afternoon when I can get it on a hoist at mu buddies shop.
Funny, I topped it up yesterday and ran it while sitting on jacks. No leaks. But over the next 24 hours I would get whiffs of gas from the carport area...and yet...the tanks is still full.

Marty

 

i have had issues in the past with the sending units getting gunked up. Some times the sediments from the fuel will attach to the sending unit and prevent the reed switch from moving up smoothly. You said that it went to half a tank, then creeped to three quarters, if you do drop the tank, look for some build up. if you are not dropping the tank, drop a fuel system cleaner in there, and maybe another one when you are lower on fuel, seeing as we do have some large gas tanks.

 

Well....got the car up on a hoist late this afternoon and figured out what was causing the leak. The two tubes entering, or leaving, the tank were moveable. I guess the original weld had failed. Tempoary fix:...Gas tank putty to hold the tubes in place. New hoses and clamps. Solved the problem. Will look at pulling the tank after the winter and having the tubes rewelded. I'll check the fuel sending unit at that time to solve the other problem...hopefully.

Marty