Clogged fuel inlet on '78 gas tank

[CG240Z]

Hey guys, some of you guys might have seen my build thread on my 280. Cars about 85% done, I need to update the thread with some new pictures, but my computer is down and I'm having to use my tablet.

Anyways, one thing that's holding me back is the small inlet on the gas tank is clogged, I'm assuming this is the return line since it is the smaller of the two. The tank was in pretty bad shape, a lot of rust on the inside, but I had it boiled and it cleaned everything up, except this one line. I've tried the speedo wire and drill trick with compressed air and carb cleaner, no luck. When I look through the sending unit hole I see the line runs into the internal filter area.

Does anybody know if I can cut an access panel in the tank, then chop the hard line before the clog. Then weld the tank back up. Hopefully that makes sense. I'm thinking if its a return line, it shouldn't matter where the fuel gets dumped back out at.

Or any other suggestion will be helpful. I've also been keeping my eye out on craigslist for a clean tank. Once I get this tank situation solved the car should be making some nice very soon!! Thanks guys!

[FastWoman]

Maybe you could put a "T" fitting on the low pressure line between the tank and fuel pump and connect the return line there.

[CG240Z]

Maybe you could put a "T" fitting on the low pressure line between the tank and fuel pump and connect the return line there.

I'm not exactly getting what you are saying. Are you saying connect the return fuel line into the output fuel line via a T fitting?

[FastWoman]

Pretty much. The return would circulate directly into the intake of the fuel pump. This configuration wouldn't do much to churn/mix the fuel in the tank, but that's not really necessary. At least it would provide a route for return flow.

[Zed Head]

Only adding this so you can be sure about what lines you're looking at. Seems like the return line would be a straight shot back in to the tank. Maybe use an actual drill bit instead of a piece of speedo cable. Worth a shot before you cut a hole.

[CG240Z]

Only adding this so you can be sure about what lines you're looking at. Seems like the return line would be a straight shot back in to the tank. Maybe use an actual drill bit instead of a piece of speedo cable. Worth a shot before you cut a hole.

Thanks for the diagram. So it is line #2, return, but its actually a 90 degree hard line coming off the tank. Then if you follow the line inside the tank it runs down the bottom and to the other side where the internal filter is. So a drill bet won't help much with this.

[EuroDat]

The return line is the small one (2) 1/4" 6.35mm line. Line to the pump is (3) 5/16" 8mm line just to clear that up.

Most people have problems with the line to the pump clogging. This one normally has filtered fuel returning to the tank so its generally not the problem. Since its been standing for a long time and boiling it could have made it worse.

You mentioned, you used compressed air. Did you try to blow it clear? How much pressure did you use on it?

That fuel line can handle 6bar pressure, just make sure the tank is open when you do it. If that is not blowing out whats clogging it, chances are your not going to get it cleaned without cutting the tank open and then is still debatable.

IMO If you are going to cut the tank. I would cut around the pipe with a dremmel and remove it. Clean it or fabricate a new one and weld it back in. You will need a plate (like downut shape) to cover the section where it was cut.

Im assuming the tank is still clean of all fuel and vapour. Otherwise you risk (almost certain) explosion.

Chas

[siteunseen]

I used a section of the stiffest welding wire I could find to punch through the tank liner that had hardened up in those.

[FastWoman]

Thinking about my solution, I can only imagine two disadvantages:

-- Without passage through the tank, the fuel in the recirculation loop could get warm (hot day, heat soaking). This could aggravate hot-restart issues.

-- The system could be difficult to prime if run dry.

[CG240Z]

I'm going to try some more speedo and welding wire action. The tank has been sitting since 95 before I got to it this year, so it's definitely gummed up.

[black gold man]

I see a tank on long island NY CList.