high pressure in fuel tank

[boilerman63]

hi i have a 1993 t4 camper it is petrol\lpg the problem is when i remove the the fuel filler cap
a lot of back pressure blows out. the breather pipe is clear i have ckecked it the filler cap seems ok
can anyone tell me where this pressure is likely to be coming from . can something be back feeding
into the tank.this is not ur normal expansion due to warm weather

[ghost123uk]

Hi Boilerman

When you say =

when i remove the the fuel filler cap a lot of back pressure blows out.

the breather pipe is clear

This surely cannot be right = if the breather was clear then pressure (or more often vacuum) cannot happen

Perhaps I am not understanding what you say correctly.

[Red Westie]

I don't know the specifics of your particular setup but some fuel tanks are part pressurized, some are not. Does yours have the original factory petrol cap fitted? as some caps are vented/ or none vented..

Like I say I don't know the specifics of yours.

Martin