fuel boiling in the tank

[86 Daytona]

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86 Dodge Daytona turbo Z runs great no problems no overheating after about a half hour of driving you can hear a hissing when you park from the gas tank and there's a strong fuel smell but no fuel leak under the hood near the canister.( I'm sure it's venting high pressure)
as soon as you open the gas cap the boiling sound stops in the hissing stops.
I've only owned this car for about 2 months changed all the fuel lines the fuel filter the fuel pressure regulator when I first got it no problems up until about a week ago.(when it started getting hot out I live in Nevada so heat will definitely be a problem.
any help would be greatly appreciated thanks

[cordes]

I'm wrong. That must be some pressure in there?

[zin]

Look for where the heat is coming from, assuming the tank is fairly hot to be boiling off fuel like you describe... Most likely source is going to be the exhaust, especially if it's been upgraded to a larger size pipe, that will move it closer to the tank.

Assuming it's not touching (which it could be), adding some insulation, either some "header wrap" or a heat shield to reflect the heat should do the trick.

If it's not the exhaust and it is confirmed that it is getting hot, I'd look at the return line, just because it's too easy to do to not, then I'd probably pull the pump, that's pretty much the last place heat could be put into the fuel/tank.

Lots of fuel vapors is a dangerous situation, very flammable, possibly explosive in the right conditions, definitely not something you'd want to put off fixing!

Best of Luck!

Mike

[turismolover22]

Rollover valve or fuel filler cap

[zin]

Those are some good places to check, especially if the fuel isn't actually being heated, and is just venting. If it is venting inappropriately, the lines going to the canister and check valves may merit inspection.

Mike

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Those are some good places to check, especially if the fuel isn't actually being heated, and is just venting. If it is venting inappropriately, the lines going to the canister and check valves may merit inspection.

Mike

[Reaper1]

I'm going to place my bets on some sort of venting issue. I've seen this sort of thing happen on boats. You will fill the tank and it won't be leaking out of the vent. Leave the boat out in the sun for a few hours and all of a sudden fuel starts to gush out of the vent!

If the car is all stock, make sure the purge solenoid is working correctly. Check the vent tubes for blockage. You might want to put a new fuel cap on it, just to make sure. If you drop the tank, be careful of the vent tube at the top because it is super easy to bust it off, so drop the tank down slowly.