That tank insulation was there for very good reason. The pressure in the
tank will equal the vapor pressure of the fuel. The heat from the
engine-transmission is raising the temperature of the fuel increasing its
vapor pressure. Also make sure the venting valve is working. It is vacuum
operated. You can usually hear it click as the throttle is opened. The vent
valve opens a port into the air filter so that any vapors escaping get
burned off in the engine.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Stephen Engel
Sent: Tuesday, May 14, 2013 8:16 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Excessive fuel tank pressure

My 87 Syncro GL 2.1 WBX releases way too much pressure, I believe, when the
fuel filler cap is opened. It may be my imagination, but the problem seems
to get worse the longer I drive and the emptier the tank is. When I first
had the van, before any work was done, the fuel sender was leaking badly
allowing any air (and fuel!) to escape readily.

The engine/ trans and fuel tank were removed and all fuel lines, grommets,
rollover vents, seals were replaced along with fuel filler neck, fuel
sender, and tank straps prior to reinstalling refurbished engine last year.
Only the cap and tank itself are original. The tank insulation was omitted
during reinstall.

Any suggestions on what could be wrong?

Thanks in advance, Steve

Sent from my iPhone