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Aftermarket Air Filter and CCV Routing on 2.5L YJ Wrangler


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I have a 1989 jeep wrangler yj

 

I took the factory air box away and installed a kn to the throttle body.

problem now is not running right and ccv is discharging oil residue over engine block

where do I hook the ccv to alleviate this issue.

any help would be great.

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yj89...Sounds like a possible disconnected vacuum source to the PCV valve or a distinct vacuum leak in the system...Below are the parts diagrams for both your air filtration system and the emissions devices and vacuum circuits.  (I tossed in the EGR vacuum source simply for more detail.)  These PDF diagrams can be "zoomed-in" for details:

 

YJ Wrangler 2.5L Air Filtration.pdf YJ Wrangler 2.5L Emissions Circuits.pdf YJ Wrangler 2.5L EGR Vacuum.pdf

 

For a quick check, with the engine idling, see if you have vacuum pull on the engine/crankcase side of the PCV valve.  Remove the hose and valve as if servicing this periodic replacement item.  Hold your thumb over the engine side of the valve, engine idling and while blipping the throttle.  Make sure there is vacuum pull.  If not, there could be a buildup of crankcase pressure causing your oil weeping around the grommet.  There must be ventilation to the crankcase.  If not, look over the diagrams carefully and see where there might be a disconnect here.

 

Parts descriptions and numbers are noted, these are official Mopar parts.  The PCV valve, if defective, can be readily replaced...I see that the OEM air box had a delay valve on the vacuum circuit.  I'm curious how K&N deals with this and also the factory thermal vacuum switch.  What do the installation instructions say about these functions?

 

Was there oil in the OEM air box?  You can determine actual engine blowby with the PCV valve out of the valve cover and the engine idling.  Remove the oil fill cap.  If you're getting a steady pulsing of crankcase fumes with an oily smoke, your engine has blowby.  Check the compression, or better yet, do a cylinder leakdown test. 

 

Others with K&N filter conversions may have additional insights to add here...

 

Moses

 

 

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yj89...Here is the vacuum circuit diagram for your 2.5L TBI engine in the Jeep YJ Wrangler.  You can see the vacuum source circuit for the PCV and also the routing of the CCV system.  The engine's crankcase ventilation (CCV) needs both the PCV draw and fresh air intake from the air filter.  The K&N system should have provided a fresh air access tube for the CCV system.  Look this over:

 

Jeep YJ Wrangler 2.5L TBI Vacuum Circuit.pdf

 

This should help clarify...Look at your original air box and induction tube.  You need both a fresh air source (must be filtered air) and a suction side on the PCV system...

 

Moses

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