Vacuum hose?

[Ducky2009]

I learned this the hard way. After setting it up incorrectly, I talking to a Ford mechanic (and paying $$), I discovered how the system actually works.

The Gen 2 Coyote has a vacuum reservoir canister under the intake manifold. The CMCV system NEEDS vacuum to hold the CMCV throttle valves open at full throttle. Without using this canister, at full throttle, engine vacuum drops off to NOT enough to keep the CMCV valves open.

The vacuum line on the PS of the engine should be connected to a vacuum supply up front. This line has a one-way valve (just to the left of the paper tag in pic #2), which allows the vacuum canister to RETAIN vacuum at full throttle, thus keeping the CMCV valve open during full throttle, and the engine now operates at full performance. NOTE: If you remove the one-way valve during your plumbing set-up, make sure you don't reverse it.


If set-up without this one-way valve, at full throttle, the vacuum drops, allowing the CMCV valves to partially close, thus reducing performance.
The CMCV's are already plumbed to the vacuum reservoir on the back side of the engine. Don’t change the existing vacuum lines at the rear of the engine..

NOTE: If you add the manual CMCV Lockout plates to manually keep the port runners open, none of this is necessary, but fuel efficiency will suffer during mild driving.