2001 4x4 7700 Bi-fuel 5.4L F-150

Hose originates from an a solenoid on the firewall and connects to it with a green clip. From the solenoid it connects to the manifold just towards the firewall from the throttle body. Before it gets to the manifold it has a T fitting that has a small black vacuum hose that goes towards the passengers side but connects to nothing I can find.

Please see Pix.




Solenoid and green connector on Drivers side. This part seems fine, but this is where the hose originates.








This is the loose end. No idea where it goes. I don't hear a hiss and don't see a spot it could connect to.<br/>

This is toward the middle of the truck against the firewall. The white plastic that the arrow is pointing to is the T fitting which has the hose coming off it that I cannot find the home to.

 

It's a mystery!

 

Plugged it with a screw for the time being. Still don't know where it goes. Have crawled under the truck, looked everywhere. So far no Check Engine Light and everything works fine from what I can tell (A/C Controls, 4wd, etc all seems normal).

If anyone has any ideas about this mystery vac hose let me know. It is NOT on the vac hose diagram either. The hose it comes off of is, but not this little hose off the T. It's odd...

 

That's part of the EVAP system, either goes to the line coming from the charcoal canister (along frame rail with fuel lines)
OR it goes to the port on the intake. I don't remember exactly where it goes off the top of my head

 

My 2003 4.6 that hose goes from the green side straight across to the top of the plenum elbow

(Under the throttle body cover)

 

I missed the part of the conversation about the T fitting Inline. Could have been a vacuum gauge installed?
Might also be related to the bifuel CNG hook up?