Vacuum hose identification (hose is missing)

[Splattercaster]

Hello,
I am dealing with a mouse nest that got sucked into my engine after the truck sat for a while. '93 3.0l. Immediately downstream of the mass airflow sensor is a nubbin for a vacuum hose, but no hose is present. When the hole is open the truck will not stay running, when it is sealed (as in the pictures, sealed with a zip tie and chunk of rubber glove) the truck runs 'as normal'.

I feel dumb for not being able to determine what or where this hose should go by looking at my manuals or vacuum diagrams. Any help?

Thanks in advance!

 

[Curious Hound]

That should have a hose going to the nipple at the base of your oil fill neck.

Here is the vacuum.hose diagram for 93, 3.0l. It doesn't show that hose.

And, in case you need it in the future. The belt routing diagram sticker.

 

[Splattercaster]

Thank you so much! I wonder why they didn't include it in the vacuum hose diagrams.

 

[Uncle Gump]

I've never owned a 3.0L...

But that isn't a vacuum hose. It's a fresh air inlet for the PCV system. This explains why it isn't on the vacuum diagram.

It also shouldn't be pulling a vacuum on the nipple... not like a manifold vacuum source anyway.

But with it left open... it messes with the values sent to the ECM from the MAF. It's allowing unmetered air into the engine.

 

[Splattercaster]

Here's what I found. No apparent location for the hose to attach. The valve covers are leaking like crazy and the former owner didn't have an oil cap for years, he was using a rag. Clues to a bigger story I suppose. Replace the covers maybe? They say "3.0l V6". I am about to replace the gaskets otherwise.

 

[Redav72]

As mentioned it's a fresh air hose for the engine. It connects from air intake hose to the valve cover. Here is a picture of mine, zoom in and you will be able to see it. Those hoses are available at any part store. Years ago when it needed replacement I bought a hose from a auto parts store, don't recall if I got a oil, fuel hose. What is in there it works as it should.

That's a terrific looking engine bay. Would you be able to post some pictures from all sides? I'm in the process of rebuilding a '94 3L and I'd really appreciate reference pictures.