All,

After hooking and unhooking various hoses on my 1992 245 with B230F engine, and testing each branch with a mityvac, I discovered that the line with the problem is the one that runs from the intake manifold to the crankcase vapor recirc tee -- that weird plastic deal with the flame trap grill in it. If I unhook the small vacuum line and plug the tee, I get the right amount of vacuum pressure in the manifold; and this, even though the big hoses from the flame trap to the intake line, and the shorter crooked hose to the engine, are not plugged.

Replacing the small vacuum line did not change it.

So: what is it about that part of the system could be screwy, such that I'm losing that much vacuum? The tee itself is not cracked, the big hoses are relatively new (the crooked one is BRAND new), and the small vacuum line is good.

Could there be some problem in the engine breather itself? Something gunked up and gunked open or closed? Frustrating if true, that engine has been fed nothing but synthetic oil for the last year and a half. I'm stumped.

For now, the tee is capped at the intake manifold so it runs at full vacuum; the small vacuum hose off the tee is just vented to atmosphere. Not optimal, I know.

Thanks in advance.