JDav's MK4 #9028 Build Thread

[Ducky2009]

Actually the connections you're pointing to are vents. On earlier versions of the Gen2 Coyote those were connected to the intake. On later versions, Ford deleted the hose to the intake and vents them to atmosphere. The vacuum signal that those switches control is on the other side.

The CMCV system gets its vacuum from the reservoir in the manifold, which needs to be hooked up to the vacuum connection at the front of the engine by the throttle body. Check this vacuum diagram for the system. This is the older version showing the vent tube to the intake. Ford apparently doesn't have a newer one.

I originally connected the supplied line (2017 is on the PS, same as your diagram. Your car pics show it on the DS) to the cold air inlet, same as you. The CMCV was open, great for performance, bad for gas mileage. I called Ford racing and they acted like this has never happened before. After talking to them a second time, that person told me the hose is no longer supplied from them, but is installed on factory cars. I also had a fault. After reading someone's (???) post, it suggested connecting to the ports as I did. The CMCV is now functioning correctly.

Edwardb - I thought it was your post that showed a hose from the intake to the CMCV connections and fuel regulator

[edwardb]

I originally connected the supplied line (2017 is on the PS, same as your diagram. Your car pics show it on the DS) to the cold air inlet, same as you. The CMCV was open, great for performance, bad for gas mileage. I called Ford racing and they acted like this has never happened before. After talking to them a second time, that person told me the hose is no longer supplied from them, but is installed on factory cars. I also had a fault. After reading someone's (???) post, it suggested connecting to the ports as I did. The CMCV is now functioning correctly.

Agreed the support from Ford on this feature isn't great. They supplied the posted vacuum diagram and that was about it. Factory Five doesn't address the feature in the revised Coyote installation instructions either. They show using the required vacuum port for the fuel regulator vacuum signal. That's it.

I went through a couple revisions to get mine to work, and ended up with the CMCV vacuum supply line on the opposite side as it came from the factory. But that doesn't matter. What does matter is there has to be a line from the vacuum port on the front of the engine by the throttle body to the connection on the back of the intake going into the vacuum reservoir. That's true for all versions. If your CMCV system is working, then yours must be connected.

I haven't gotten a CMCV DTC since mine was plumbed this way, now approaching 1000 miles. Just today was doing some data logging, and can see in the data where the PCM is commanding the IMRC valves to open and close. With no codes, they are apparently doing what they're told. Hopefully yours is the same.

No need to continue this discussion in Joel's build thread.

[jdavis500]

Joel,

Your red outline of the CMCV plumbing made me do a double-take. Just sayin'...

[Jdav]

Joel,

Your red outline of the CMCV plumbing made me do a double-take. Just sayin'...

It does have a certain shape that I'm sure most of us are familiar with