[scottfab]

only thing I could find on gas cap pressure testing wast this from the EPA. It seems to allow for a certain amount of leakage.

Are people seeing a true pressure build up OR a vacuum build up?



Gas Cap Test
(1) Cap Installation. The fuel cap, or caps, shall be removed from the fuel inlet(s) and installed on
a portable or bench test rig using the adapter appropriate for the gas cap as specified in
§85.2227(d)(1)(ii).
(2) Leak Measurement. The gas cap leak rate shall be measured and compared against a 60 cc/min
at 30 in. WC flow standard. Pressure decay measurement using instruments with a 1 liter head
space shall be made from an initial pressure of 28 in. WC and be compared against a loss of 6
in. WC in 10 seconds.
(3) Cap Replacement. The fuel cap(s) shall be replaced on the fuel inlet and tightened
appropriately.