Fuel Heating Up - First Gen Vitz/Yaris

[Owais Yunus]

Hello all. Hope you're doing well.

I've had a problem with my 1.5 Vitz for some time now. Its a 3 door vitz with a 1nz swapped into it. A few months ago, the car stopped in traffic and wouldn't start for some time. When I opened the fuel filter/pump housing, I found out that the fuel inside the tank has boiled to a point that the pump no longer works. It was so hot that I couldn't touch the fuel. Suspecting the pump, I replaced it with a new one, only for it to happen again. Fuel boiled and weakened the pump. This has happened quite frequently and I've changed 4 fuel pumps now. The 4th brand new pump has started warming up too. Previously, it used to take some time to warm up. Now it warms up quite soon.

Things that I've done are as follows.

1. Suspecting the exhaust, I wrapped it around the fuel tank area with no help whatsoever.
2. Replaced the fuel filter and strainer.
3. Replaced the intank regulator.
4. Checked the evap system thoroughly.
5. Tried running the car with the fuel cap open to avoid any vacuum buildup.
6. Checked the wiring and voltages and ground.

This issue has been really bugging me and I cant really drive the car for more than a few kms before the pump starts dying. Any help in this matter would greatly help!

Regards.