Catch Can N/A VQ37VHR Burning Oil/Smoke

Originally Posted by projectpanda

I know this is an old thread but wanted to share my similar experience. The rear ports on the valve cover needs to be able to breathe, so DO NOT CAP. I made this mistake and after 60 miles of high rev driving, my oil pressure light came on and when I checked my dipstick, there was so much vacuum it pulled the stick back down
My setup that caused this was capping off the rear ports but kept the pcv port stock. I didn’t have a filter to put over the rear port but I still left it open to breathe and it was fine afterwards.

I have since drilled into my intake to mimic the factory setup with an oil catch can on the PCV side.

Originally Posted by Jonathan-NEX

Hey I know this is an old post, but I am having the same issue with my set up. i installed the catch can the same way you did, and I forgot to open the backside valve covers causing pressure to build up and the same thing would happen when I would open the oil dipstick. I proceeded to add hoses with little filter breathers attached at the end, and that got rid of the oil pressure problem, but then I received a code P0171, running lean on bank 1, what do you think I may be doing wrong?

Here are pictures of my current set up

Originally Posted by ByThaBay

You're pulling in unmetered air through the breathers. Your fresh air intake has to be taken AFTER the maf sensor meters the air. If you take in air from a breather, that's "unmetered" air going directly into the manifold.

breather -> valve cover -> pcv valve -> intake manifold = vacuum leak

Originally Posted by Jonathan-NEX

How can I fix that problem, and thank you for replying!

Originally Posted by ByThaBay

Get rid of the breathers and connect the hose to an air source after the maf but before any forced induction or throttle.

Originally Posted by Jonathan-NEX

Since my intakes do not include the hole to connect the valve cover to, where should I get the air source from?

Originally Posted by ByThaBay

Anywhere between the maf and throttlebody - there are no alternatives