i have a 91 civic with a D15B2 replaced the distributor, valve cover gasket and spark plug seals it goes through maybe a half a court every week and i drive it about 800 to 900 miles a week and it seems like its leaking from the oil cap there is black burnt oil on the PCV on the manifold i dont know if the breather box could be clogged so the engine might not be venting right if you guys can help please let me know thanks

 

Are there any external oil leaks? If so, where are they located.

Civics of this vintage suffer from piston to wall clearance problems that will accelerate oil consumption. The valve stem seals are also another point of leakage.

Remove the oil cap with the engine running and place a piece of thin paper over the fill hole. The paper should buzz over the hole, but remain in place. If the paper blows off and sucks back on over a greater distance, evaluate the PCV valve an flame arrestor (the black box) for blockages. If you cannot find any, your culprit is the rings or valve stem seals barring any external oil leaks. Removing the spark plugs and inspecting for ash deposits can help verify this.

Have you modified the air intake or PCV system in any way?

Source: Owned a D15B2 for 8 years, oil consumption for me was caused by bore wear/frozen oil rings, which is typical of this vintage.

 

Well I took the oil cap off and its pushing out a bunch of air havnt checked if the hose to the pcv has suction or not but going to check it later tonight

 

So I sucked on the hose for the occasion with the oil cap off and it made vaccum. And with the car running I took the hose off the pcv and it looked like black flakes were coming out and the top of the pcv was black. So what do you guys think should I clean the breather box and pcv and see if that helps or do you guys think its blow by the rings

 

Well I'm an idiot I went and put the paper over the fill hole and it was buzzing so I'm going to clean the breather box and change the pcv and I hope that helps