i used to work at a gas station and noticed pumps stopping before they were done filling too. our problem was caused because of the pressure build up in the tank. to solve our issue we had to hold the rubber seal part up so that air could go in and depressurize the tank.
too much pressure shouldn't cause gas over filling though.
2013 Le Mans Blue M3 - ZCP :: Lux v3 :: Protech Film
Project Pictures :: My M3
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