Re: 1/2 teaspoon of oil+fuel? on engine top
Got his from another automechanic's website. This small drop of oil/fuel I have found has a lot more meaning to it. This could be A reason why my idle rpm is fluctuating.<br /><br />""Well, to get to the heart of the matter, you need to CHANGE YOUR OIL at timely intervals! That, and that alone, will prevent almost all PCV valve problems. PCV valves plug up with sludge. Sludge is old oil. If you need to change your PCV valve, chances are somebody's not been changing his oil often enough for driving conditions. And chances are good that you'll need to some serious cleaning of lots of other things on the engine, like the throttle body and Idle Air Control Valve.<br /><br />The system consists of a small air intake breather hose mounted in the intake tract before the throttle body, and the PCV valve, which is typically in the intake manifold or the valve cover. Air flow is from the breather before the throttle body, through the crankcase, up the PCV valve and into the intake manifold after the throttle body. It's basically a controlled air leak, with the PCV valve acting as a one-way check valve that has adjustable flow characteristics.<br /><br />If the PCV valve gets plugged, here's what happens, roughly in order:<br />1. Excess crankcase pressure begins to back up the engine's breather tube, into the intake air tube upstream of the throttle body <br />2. Engine management system senses absence of air from plugged PCV valve, and adjusts fuel mixture accordingly. Engine makes slightly less power. <br />3. Oil begins to be pumped into the air intake tube through the breather hose, upstream of the throttle plate. <br />4. Oil runs down the intake tube into the throttle body. <br />5. Oil sludges up the throttle body and throttle plate. Idle Air Control (IAC or EACV) valve gets contaminated and begins to stick. <br />6. IAC cannot adjust idle air mixture to compensate for plugged PCV valve. Idle drops, may become erratic as throttle plate cannot close completely. <br />7. Oil drips into intake manifold runners. Blue smoke seen out of tailpipe. <br />8. Breather tube begins to get constricted from oil contamination and airflow is reduced. Crankcase pressure mounts dramatically.<br />9. Oil pushed past valve guide oil seals. More blue smoke. <br />10. Dripping on driveway as oil is pushed past seals. <br /><br />End of quote
