I was just doing some routine inspection of the condition of my star hoses and vacuums lines. I was checking the fit of the vacuum line that connects the fuel pressure regulator to the intake plenum. This is a 502mpi with cool fuel. Anyway, when I pulled the line off of the regulator oil began to flow out of the line. Pretty sure there should not be any oil in that line which tells me there is probably more oil be drawn into the plenum from the valve cover/PCV valve than normal. I have a K&N filer which has a vent connection to one valve cover (no PCV value just a 90 degree elbow) and a PCV valve in the other valve cover which is connected to the plenum underneath/front of plenum. I think this is stock set up from Merc. Is this indication of a bad PCV Valve? My valve covers are not stock and I do not see baffles in the value covers when I look in the grommets.

Thoughts? Thanks

test suction at the PVC valve - it should leave your thumb stuck to it while the engine idles

I was thinking possible bad fuel pressure regulator or very high crankcase pressure or thinking out load as alot of blow by ??? Maybe leak down test needed as well.. Have to think a bit more about all this.

What year and engine serial number is your app ? Also is it 100 % stock app or what ??? Added aftermarket SC ?

Pcv is under the intake.

Motor has a AZ Speed & Marine honed intake, fuel pressure regulator, K&N Filter, reprogrammed ECU.

Is it, trying to remember my mpi units, I know the 500 & 525 efi its in the bottom center of the intake, I thought my 502's it was in the valve cover

Yea, the PCV is at the valve cover in this 502. hose runs from PCV vale at valve cover to underneath the from of the intake.

Non baffled valve covers using a PCV usually ends up with bad results.

That's what I was thinking. The baffles prevent the essentially block the oil correct?

One would have to ask how much oil then is the PVC valve and its line ?

There was no mentioned of it so my thinking that oil was not going threw the PCV valve / system unless I totally misunderstood the first post.

OP already mentioned the PCV valve was in the valve cover in his first post. just saying

I've had quite a few MPI manifolds apart the were full of oil and fuel. Engines still ran fairly well...