air on return fuel tube

[taz131]

I got a 320i 1985 ,sometimes starting it isn't easy.
When hot and with the gas tank full,when the pump starts I can hear a loud bubling inside the tank.
But i already put a small clear tube between the fuel filter and the injection ramp and can't see no air passing so I'm assuming it isn't coming from the pump.
Is this normal ?

[Starmavin]

Most likely it's the sound of return fuel from the regulator pouring back into the tank. However it's odd that you can hear it so loud.

[taz131]

When the engine is running ,and with a clear tube on the exit of the pressure valve regulator I can see very small bubbles coming from it.witch I can't understand why ,because like I said i do not see it coming from the pump. About the sound it's like if you blow on a tube inside a bucket,some times after the pump works and stop,if turn the key off and on I still have a little more bubbling.
Otherwise works ok.

Thank you.

[Starmavin]

Very unusual. Does your fuel return line get close to the exhaust?

[taz131]

No the fuel lines go near the driver side ,every thing is standared.