Easiest way to do the fuel leak down test is with a fuel pressure gauge.
Bentley says system should hold pressure (30 psi or so) for several minutes
after shutdown.  If your gauge comes with an open hose adapter, slip it over
the fuel tap near the distributor, and use a clamp.  Otherwise cut it and
splice it with a brass barbed coupling for other cars. Get the type that
drains any residual gas out a separate line. Instructions here, including
safety procedures: https://www.youtube.com/watch?v=QsqBJxKj1KQ

Do it soon, backfires are hard on the AFM. I've used mine many times over
the past 40 years to diagnose fuel system problems.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dennis Jowell
Sent: Saturday, May 16, 2015 3:19 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Start up,back fire?

Question on why do I sometimes get a backfire from my 2.2 GOWESTY WBX.
yesterday I drove the 88 gl Westy an 1.5 hr pulled over to check my GPS,
shut the engine off. Then 2 minutes later started it and "bang" it
backfired, it did start. Shut it down and tried again same thing. Drove home
it didn't occur again. Any thoughts of what is going on? The new  Engine has
about 5000 miles on it. Maybe to many mice running around in there.

Dennis Jowell
Scotch Hollow Farm
Newbury, Vermont