Fuel line coming off

I have an interesting problem. An In-tank fuel line is giving me fits. It goes from the outlet of the pump to the bulkhead fitting for the tank exit. The fittings are hard, slippery plastic. The fuel line inside the tank (proper submersible line) has popped off twice and has been cut by excessive clamp pressure once. To make it interesting, the two fittings are different sizes. There's 60 psi in the hose.

The factory deals with this by using a plastic corrugated line that's heat-shrunk on. Due to our size mismatch, this is not an option.

Any ideas? I'm tempted to glue it on if I can find a fuel safe epoxy.

Brass barb adapter in tank with correct size hoses on each side?

That would be great, but I'm not sure we can get the barbs attached to the plastic. I'll check sizes, we might be able to cut threads in it and use female NPT adapters.

Looks like Loctite E-120HP epoxy may also do the trick.

Does the line have to be able to move and flex?

The times I have seen rubber hose in an OEM application seemed to always involve the two barbs being so close together that the hose physically couldn't blow off. I wonder if you could approximate this with a section of hardline, but this would only work if it didn't have to articulate or change length with assembly.

Does there exist an alternate fuel pump with a more appropriate outlet size?

I just changed a water separator on a diesel truck that used plastic lines and barbs. A real pain to install unless you use a little heat gun. That is also how you move the fuel line on a 4.6 S197 mustang when changing the intake. One shot deal, cut the line and reinstall the barb in the plastic line. NO pressure just don't melt it or you are screwed.

is double/triple clamping an option? it would depend on how long the plastic fittings are.

Wrap safety wire in front of each clamp and tie it back to behind each fitting??

The reason we've done this is because there are no high flow pumps that fit in the housing. The stock unit is admirably short. So we've combined parts to get a high flow pump in there.

The plastic fittings are on the housing that contains the pump, not the pump itself. They're actually barbed, but clamping just isn't holding them.

We're going to pick up some nylon hose and see if we can heat-shrink it into place, similar to the factory setup.

Going to brass might work on the big one, a 1/8 NPT female would work. But the smaller one is just a bit too small. We'll see when the pump assembly what the latest failure was. Oddly, the last time it popped right off it came off the big end.

This just in: latest failure was...out of gas.

Sigh.

For some reason, the fuel gauge wasn't reading properly. Must be the CAN system, although it bench tests fine. The good news is that we now know an ND Miata will suck the tank absolutely dry.

The clamps on your hose are staying on the hose and likely will so tie the clamps back to the fittings and you'll likely be set

Tying them back is harder than you might think, there's nothing to tie to.

Funny. I just watched a Roadkill episode where the '55 wasn't running right, but it was just out of gas.

I've had it happen before, enough that the first thing I did last time was to throw a few gallons in it. But not this time, as the symptoms were identical to the last time the hose popped off. One cough and dead.

Man, you want a tutorial in how complex modern cars are, you should see the logic on this fuel gauge. We were messing with the fuel injector pulse width signal transmit to see if we could get the range calculations working, and it "locked" the gauge. It only runs purely off the fuel level sender when you're refuelling (VSS at 0, change of 2L or more). Lots to learn.

^That's kinda crazy. Makes me curious.

You should see how the reverse lights work. It's nuts. I understand why, I'm comfortable with computers and I know it'll be far more reliable than a big bundle of wires - but I would not want to work on this car without the right documentation or tools.