F225 Relief valve and air orifice vent?

[bobterisch]

Hi all,
My 2002 F225 has a 69J-13490-00-00 relief valve into the air intake. I was looking at the parts diagram for a 2005 F225 and it has both of these parts off of a tee going into the air intake.
69J-14989-00-00 ORIFICE, AIR VENT
60L-13490-00-00 RELIEF VALVE ASSY
Anyone know why and/or what the added air orifice vent that was is for?
Thanks,
Bob

[fairdeal]

the 2005 has a carbon canister on the VST vent line, as well as the "orifice" going directly to the intake silencer.

The "orifice" does not seem to be a "mechanical valve" like the "relief valve assembly" but rather just a very low flow restrictor.

The vapor that makes it into the carbon canister via the one-way "relief valve" seems to be eventually "sucked back out" through tubing to the IAC valve.

[fairdeal]

here you can see the "orifice"
coming from the "tee" in the VST vent tubing
and going to the intake silencer






upper left: the "relief valve assembly" in the VST vent line,
acting as a one-way pressure relief to the carbon canister

[bobterisch]

Got it.
Thanks for the reply.