Air present at schrader valve, engine off?

[EvergreenRanch]

hey with the engine off (hot or cold), if i depress the schrader valve at the fuel filter, should there be air present? i get a small hiss of air being released (about a full second worth low low psi), which will re occur if valve released and i wait a few seconds......is this indicative of air leak in the fuel system? if so how do i correct issue?

 

[Ironman03R]

Mine is the same way. I think its normal. I can't drain the water out unless I let the air out at the schrader, then it will start to drain. I know that theres a ford bulletin about that so I never put any thought into it.

 

[Cowboy_Customs]

If you happen to find out what the problem is please let us know, I have been battling an air issue for months, I have replaced EVERYTHING in between the rear tank, and the cylinder heads!

 

[wwwabbit]

Just thinking out loud... but I think the "hiss" is air being sucked in as the fuel drains back... At that point (with the engine off) there should be no preasure in the fuel system. Any preasure should drain out through the return line at the injection pump with out the lift pump operating.