2001 Ford Explorer - Unknown Part

[Westley]

I have a 2001 Ford Explorer. The PCV valve is positioned behind the intake manifold in a tee fitting. The two out hoses connect to the upper intake. The feed hose goes under the lower manifold and goes into a small box that is on top of the engine. What is that box and should it move?

I have two lean codes and can hear a hiss. A mechanic told me it was the lower manifold gasket and I replaced the upper and lower gaskets. While the lower was off I noticed the box connected to the PCV line. It is under a wire harness but i grabbed it and noticed it was moving a little, ie. not secure. I didn't much of it until I had the manifold up back together and the problem persisted.

Any thoughts?

I'm new hear but love the site and it has come in handy in the past. Just my first post as most of my questions are answered in existing threads.

 

[FIND]

Spray a little carb cleaner around your engine bay with the engine running to find your leak. Note where you are spraying when the idle changes.

I can't really think of what you are talking about, a picture would be helpful.

 

[Turdle]

I think PCV is being mistaken for what is actually EGR?

 

[Westley]

I've tried the carb cleaner method with no luck, but that was after I did the manifold gaskets. The problem, if my suspicion is correct, is that the part in question is under the lower manifold. I would have to use a hose to direct propane or carb cleaner under the manifold. Which is fine, I just haven't tried that yet.

I have searched for a reference to the part and can't find any diagram that shows it. I can't take a picture without removing the intake manifold. Which I'm probably going to do Sunday.

Below is a picture I found on this site....

So you can't see any but the lower corner of the part. Kinda silver under that wire harness near the middle of the heads. You can see the bottom PVC hose, valve has been removed, coming from the back of the heads. I think this is a different year explorer looking at the coil pack, but that part looks identical on mine.

Could it be a filter?

 

[Westley]

I think PCV is being mistaken for what is actually EGR?

No. I am a novice "mechanic" but it is definitely the PCV tube running from the engine through the valve to the upper intake. The EGR is located on the front of the engine and feeds into the manifold through a rigid tube.

 

[FIND]

I'm still not following you. You mean the fuel pressure regulator at the end of the fuel rail?

Circle it on the picture with MSpaint or something.

 

[Westley]

Yeah, sorry it hard to see what I'm talking about.

So the green circle is where the PCV valve is installed. The red line follows the hose to the box in question. It is outlined by the magenta or whatever color that is on the screen. It is under that wiring and sits on top of the engine block.

My other question would be since the pcv valve regulates air flow, would a leak before the valve connection to the manifold even act like a vacuum leak?

But I really want to know what the box does.

 

[2000StreetRod]

crankcase breather

I suspect that you are referring to the crankcase breather. It is located forward of the plate that covers the oil pump drive gear.

The Mustang SOHC V6 does not have them so they need to be added when replacing the stock engine with a Mustang engine.

 

[Westley]

So I isolated the pcv system and ran some some through the system. The part in question is definitely leaking. So I'll probably take it off this week and put up a picture when I get it off. It does look like the picture above this post. I just don't know why a breather would be right before the pcv. Many pcv valves it right into the valve covers.

Thank you to all that replied.

 

[2000StreetRod]

screen at base

There is a screen at the base of the crankcase breather. I think the idea is to keep crud from clogging the PCV valve.

Air flow thru the crankcase:
1. Hose downstream of MAF sensor provides fresh (metered) air to right valve cover
2. Air flows from right valve cover thru crankcase up into breather
3. Crankcase fumes flow from breather to PCV valve
4. Crankcase fumes flow from PCV valve to left and right side of upper intake manifold
5. Crankcase fumes are sucked into combustion chamber and burned

Some members have found the hose between the breather and the PCV valve completely disconnected.

 

[Westley]

There is a screen at the base of the crankcase breather. I think the idea is to keep crud from clogging the PCV valve.

Air flow thru the crankcase:
1. Hose downstream of MAF sensor provides fresh (metered) air to right valve cover
2. Air flows from right valve cover thru crankcase up into breather
3. Crankcase fumes flow from breather to PCV valve
4. Crankcase fumes flow from PCV valve to left and right side of upper intake manifold
5. Crankcase fumes are sucked into combustion chamber and burned

Some members have found the hose between the breather and the PCV valve completely disconnected.

Thanks for the breakdown. That is the part. My second question would be if a leak there would cause a significant vacuum issue. Doesn't the PVC regulate the flow of air? Or is it still unmetered air. I guess it would be a the intake for the PCV system is downstream of the MAF. But I don't know.

 

[2000StreetRod]

unmetered air

. . . My second question would be if a leak there would cause a significant vacuum issue. Doesn't the PVC regulate the flow of air? Or is it still unmetered air. I guess it would be a the intake for the PCV system is downstream of the MAF. But I don't know.

If the connection between the breather and the block is not air tight, unmetered air could be pulled thru the leak and into the PCV valve by the intake manifold vacuum. If the leak were significant, it would only be at idle when air flow into the engine is low and vacuum is strongest. The IAC valve should be able to compensate for the flow to keep the idle RPM within normal range but the PCM would have to adjust the fuel trims to keep the air/fuel ratio from being lean. When a fuel trim reaches the limit the PCM sets an associated DTC.