I tugged on the little hose on the back pass. side of the engine,(5.4),...
and I could hear the vacuum leak that is apparrently causing the erratic idle, and PO171 & PO174 to come up.
I know this hose is hooked to the Charge motion Control Valve on the back of the manifold,..I can't imagine what it does, as it terminates with some kind of plug or checkvalve??? Haynes say's to remove the entire manifold to get to the CMCV. Have any of you guys ever had to deal with this?
I can see it with a mirror,.I'm thinking maybe looong needle nose from Harbor freight,...bend the tip short,..maybe be able to change it out?????

 

Where do you suspect the leak to be? is it at the connection behind the intake, or can you determine any cracks/breaks in the hose?

 

It was basically a case of the vacuum fitting getting sloppy from solvent or something getting on it,..and leaking,..I will post a thread with pictures...

 

Ok,...here is a picture of the back of an '04 5.4 intake manifold showing the vacuum hose that goes to the pressure switch on the right fuel rail.
The one in the pic. is a new one I picked up at Ford for $37.00,..
2nd pic. is the new vacuum 90,..next to the loose fitting old one, that I suspect got solvent on it.
3rd pic. is simply the engine bay...I get it running tomorrow,..but I'm confident the idle will be fixed...

 

I know this is an old thread, but they must have changed this for the 2005+ (or maybe the 2004 new body style) because my 2005 doesn't have this fitting.

 

If it is a 5.4 2005. It has this fitting

 

Mine is exactly that, but I don't have this fitting. I just removed the entire intake plenum a couple weeks ago to disassemble and clean the entire CMCV system. The only vacuum fitting on the back lower area of the intake plenum was on the driver side and serves as the vacuum feed for the brake booster. The vacuum hose at the fuel pressure sensor on the fuel rail goes to a different connection on the driver side of the engine. Nothing attached to the lower back passenger side of the intake plenum.

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Hmmmm,...that's a new one on me ,...why did you pull the intake ?

 

My '05 doesn't have that port either. Well it's there, but not drilled out. I don't have that heat shielding insulation around the manifold either. Can other '05+ owners verify this?, just curious...

 

I had a rough idle and I wanted to inspect the intake plenum to cylinder head gaskets for leaks. The CMCV flaps were coated with crud so I disassembled them and cleaned everything. It made a huge difference in how my truck runs and the rough idle is gone. No evidence that there was a vacuum leak. 88K miles.

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Pardon my ignorance here. But why do you have to remover the intake manifold to clean and service the CMCV? I don't have one of these trucks, but my wife and I are planning on looking at one on Saturday and unfortunately it has the 5.4. We are thinking of replacing our 98 Expy.

 

There is no way other way to get to it. The flaps sit right above the intake ports on the heads.

 

Here's a pic...(notice lack of the insulation around the manifold)

 

oh ok thanks guys. My next question is, are the intake gaskets reusable? or do they need to be replaced each time the intake is removed?

 

The 5.4 is a good engine. It has its problem areas, just like virtually every other engine. A friend at work has a 2005 F150 with the 5.4 and ~140K miles and zero cam phaser noise. The only "major" problem she has ever had with it was one of the screens for the VCT solenoid broke and jammed the solenoid. The truck would barely run because the driver side camshaft was jammed in the full retard position. She took it to a shop and they told her the engine was seized and it would be $6500 for a new one. I asked to take a look at it and discovered the real problem. It was a $50 part and a $13 seal. The passenger side was getting ready to break too, so we replaced that one as well. For less than $150 in parts, her truck was fixed. I also changed all her original spark plugs at 136K miles (same time the solenoid jammed). Six of them broke but I got them all out with the Lisle tool. I charged her $360 in labor. It took me about 8 hours. Also cleaned her throttle body and mass air meter. The truck runs like it just came off the assembly line now. These engines do need routine maintenance and proper oil change intervals with the correct oil and filter, but if you take care of them they will run for a very long time. I put an Edge tuner on my 05 Lariat SCrew 4x4. It has 88K miles. After cleaning the CMCV flaps and running two bottles of Gumout with Regane in a single tank and on setting 2 of the programmer, it will absolutely destroy the rear tires if you floor it from a standing start on dry pavement. Even before the programmer it would break the rear tires loose starting from a stop with more than 3/4 throttle. 3.73 rear gears. This engine has great power and I'm very happy with it. I do have the cam phaser noise. I will fix that this Fall. I know where I can get all new Ford parts to do a complete job for less than $600.

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