Oil presence in intake air system / Cavalier 93

Could somebody give me advice on this: My car has been working ok for a while. Suddenly it began trashing with black smoke. Begining to check the air intake system I found oil in the air filter
and all around!! The mechanic cleaned almost anything (filter and sensors) with no use. Changed the O2 sensor , no use. Changed mi ECM with another one I have. It worked ok, but still trashing ( a little). I don't have any repair manual for this car. Everything I have it's from the web. I need to know where are the MAS and MAP sensors. I'm almost sure it's one of them, but cannot tell.
Thanks in advance! Edgar
PD. I cannot feel secure with my family in this car anymore. Am I right or just exagerating?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A high Volume of Oil in the Air intake system means one thing, High Crankcase Pressure. There are a few things that can cause it.
1. A fault in the Positive Crankcase Ventilation system. 2. Excessive amounts of Compression Blow By. 3. Excessive Oil Levels.
It does not matter if your 93 Cavalier has the 2.2, 2.3/2.4 quad 4, or even the 3.1 V6. The ECM, O2, Mass or Map sensors, for that matter no electronic controls of any kind will cause this issue. Any Mechanic that believes Crankcase pressure is regulated by any forms of electronic control needs not to touch a car.
If you have a 2.2L 4 cylinder or a 3.1L V6: 1. Change the PCV valve. 2. Check the PCV hose and vacuum supply for blockages or cracks. 3. Check the vacuum with a Vacuum Gauge A. If no Vacuum or little is found, replace or repair the throttle body. B. If sufficient Vacuum is found check compression. 5. If compression is with in tolerances, on all cylinders, remove Valve cover(s). Check that the Oil Return gallies are not blocked. Then start motor, and check for pressure coming thru the return gallies for the oil system. A. if none is found, recheck compression on all cylinders, and do a leak down test. Do cold, then hot.
B. If pressure is coming thru oil return gallies, remove cylinder head(s). Check for bad gaskets or cracked heads.
If you somehow happen to have a Quad 4 car (Rare before 95), disconnect the oil separator tube, and see if problem stops.
Charles
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.