Fuel Tank

[81dmc]

I have had a problem with fuel overflowing when filling my car. No matter what direction I point the damn nozzle, I have to end up cleaning a mess in my trunk. However, I have the fuel tank out for cleaning and I noticed a metal line that runs from the breather to the highest point of the tank. Is it possible for this to clogged?

[Jonathan]

Where do you see/think the fuel is actually overflowing from? Is it up at the gas cap opening or somewhere down lower like the top of the fuel pump or sender?

Reason I say is that when I did some fuel pump work, my tank overflowed the first time I got gas. Turns out, when I had the fuel pump out and then reinstalled it, I hadn't quite pushed it all the way down and since it needed to go down another half inch or so, there wasn't a seal at the boot.

This was where the overflow occurred, but more importantly, it is the reason why it overflowed. Why? Because when that small amount of air was rushing out of that opening, it fooled the gas pump into thinking there wasn't the necessary back pressure to get it to "click off" automatically. So once the tank got right full, it got the back pressure needed to click off, but only after the last two litres or so went all over the ground from the top of the tank, down over the frame and below.

You might be right about the breather line. I'm not sure what being clogged would do as my overflowing came from sort of the opposite problem, with there being an extra air pathway to escape as opposed to one less.

[81dmc]

Where do you see/think the fuel is actually overflowing from? Is it up at the gas cap opening or somewhere down lower like the top of the fuel pump or sender?

It is overflowing from the gas cap opening, and when it happens, the tank is nowhere near full.

[Jonathan]

Ok, got it. So, almost like "spilling" more so than technically "overflowing?"

If you have the access cover in front of the fill tube removed (below the gas cap and master cylinder access hole), you can have a look at the fill tube itself. From what you've described, sounds like it's not a problem down in the tank, but confined to the fill tube. Can you see that it is secured into the top of the tank properly and no other reasons why it might be blocked or pinched or kinked? I don't know what the likelihood of something getting stuck halfway down your fill tube and causing a blockage is as I've never had mine out or looked down through it. Did you have that fill tube off the car when you did your work?

[81dmc]

Ok, got it. So, almost like "spilling" more so than technically "overflowing?"

If you have the access cover in front of the fill tube removed (below the gas cap and master cylinder access hole), you can have a look at the fill tube itself. From what you've described, sounds like it's not a problem down in the tank, but confined to the fill tube. Can you see that it is secured into the top of the tank properly and no other reasons why it might be blocked or pinched or kinked? I don't know what the likelihood of something getting stuck halfway down your fill tube and causing a blockage is as I've never had mine out or looked down through it. Did you have that fill tube off the car when you did your work?

The fill tube is fine, but when air pressure is applied to the tank through the fill hole, it slowly decompressed through the metal air vent line. To my understanding, the vent should be more free-flowing to allow fuel to be filled at a faster rate.

[Jonathan]

The fill tube is fine, but when air pressure is applied to the tank through the fill hole, it slowly decompressed through the metal air vent line. To my understanding, the vent should be more free-flowing to allow fuel to be filled at a faster rate.

Ok, I see what you're saying. Maybe someone else more knowledgeable on how the system works can chime in, but I thought that metal vent line was only supposed to catch fumes through routing back to the charcoal canister and not actually allow a free flowing amount of air through it? I don't know for certain to be honest, but that vent line seems to be the focus of your issues, so hopefully we confirm its real purpose.

[jmettee]

The metal Line is listed on the parts diagram as a vent tube, but I think it's also for static dissipation. Regardless of that, my car "volcanos" fuel when filling with the nozzle on full blast at most pumps. I usually decrease to 1/2 to 3/4 on the pump trigger when close to full to prevent this. I know my vent lines are clear, so I think it's just that some pumps flow too fast for the tank venting design.

[PJ Grady Inc.]

I agree with you Justin. Most pumps flow too fast at "full speed" than any Delorean I've seen can handle. Have you tried just slowing it down 81DMC?
Rob

The metal Line is listed on the parts diagram as a vent tube, but I think it's also for static dissipation. Regardless of that, my car "volcanos" fuel when filling with the nozzle on full blast at most pumps. I usually decrease to 1/2 to 3/4 on the pump trigger when close to full to prevent this. I know my vent lines are clear, so I think it's just that some pumps flow too fast for the tank venting design.

[Jonathan]

Thanks Justin. And agree with you and Rob both on the slow down towards the end part. I do that myself and assumed that trying to think of other explanations. Could be as simple as that for a "fix."

[Slammer]

There's a trap door in the gas filler, are you sure it's moving freely and not stuck?