High Idle And Exhaust Smell In Cab Loss Of Engine Oil (Solved)

[jeepdoggydogB]

Like the title says, I had high idle with an exhaust smell in my cab and a loss of engine oil with excellent compression and no smoke from the tail pipe. Folks told me to check for an exhaust leak in the manifold, check for oil leaks into the valves, check O2 sensor, IAC, TPS which I did and guess what I found? The plastic tube with rubber ends that connects the crankcase to the bottom of the airbox had a leak. Had large amounts of oil residue in the bottom of the airbox and a hole in one of the rubber ends of the plastic tube to the airbox. Replaced rubber end, topped off oil and no more exhaust smell in the cab or high idle. I am trying to figure out why oil is spewing into the airbox, as I have heard of this happening with pre 91 Jeeps and the PVC, but not 91 + Jeeps.

[Stacks]

One cause could be blow by. I'm not familiar with how the CA. engines are plumbed but it could also be a restricted or plugged vacuum line from the valve cover to the intake manifold.

[HOrnbrod]

Joe, I had pretty good blow-by in my 91's original engine and did the 97+ CCV system upgrade and it cured it completely. Blow-by was common on the early HO engines, thus the factory fixed it by using larger diameter elbows and CCV hoses to make it breathe better. Here's the writeup on it:

 

http://www.jeepforum.com/forum/f310/4-0l-ccv-elbow-removal-guide-tips-write-up-733669/

[jeepdoggydogB]

Thanks Everyone.....originally I thought I was going to be spending $5000 on a new engine, but this information has been very helpful!