Question for my more experienced colleagues out there in 'trolland'.

Can anyone tell me how I can stop the 10 second purge of fuel from the sub tank back into the main fuel tank upon start up in my 2000 series II GU wagon?

I find it really annoying when I fill the sub tank on the grounds it's there for reserve, only to have it ekked away every time I start the bus...

Any assistance or guidance that could be provided would be greatly appreciated.

Cheers

DD