Emissions made simple

My response is based on my 90 YJ 258, but I think everything still applies. I would be concerned about cold weather drivability because you will be loosing source for preheated air. There is also a trap door in the snorkle that blocks air when the engine is inoperative. I am not sure what this is for, maybe to help prevent dieseling after shutting engine off. If loosing these functions isn't a problem, why not cut the sides off of your factory air cleaner and relocate the thermal air switch to where the thermal vacuum switch (which wouldn't be needed) is. You would retain Pulse Air connections and could repaint the housing to fix the rust. I have never heard of anyone doing this, so I don't know if/how it works. BTW, I bought a K&N and installed it in the factory housing. Lucky for me, this appears to have activated the automatic air cleaner oiling system on my 258. : )

jerry

Is there any way you can clean up the original air cleaner and re-use it? K&N makes a filter that fits it. It is apparent that you have been doing your homework...good job.

Important sensors:
TES: The computer uses this one to know when the air temp is high enough so it can addjust the carg correctly. It is also used with the temp switch on the intake madifold. On my jeep the manifold wire broke and the engine ran like S*&$ until i fixed it.

The TVS is used by the EGR valve to reduce the vacuum to the EGR once the outside air is warm enough....this is the one emmissions device that I have disconnected...the switch is bad (does not reduce vacuum)

The TAC controls the bypass door for your heat riser....helps you run on cold mornings. This is also used in conjuction with the heater element in the intake manifold...if you look down the intake where the carb sits, you will see a round pad of short rods sticking up....under this is an electric heater that warms up the air on cold mornings....the relay is on the firewall.

The Pulse Air system is tied to the air cleaner just so it can have clean air....its a good design that does not hurt performance at all but helps keep the air cleaner buy burning off unburnt gas.....I have considered making a seperate filter just for these hoses....

PCV....on my jeep its tied to the valve cover.....what I think your talking about is the vent....this hose vents the engine when the PCV is closed....you need to this one....it runs the oil smoke your engine makes back into the carb....without it you will get those oily spots all over your hood or other parts of your engine...plus its a major source of VOC's.

About the only way to stay legal is to use the old air cleaner. I would clean and repaint it. If this is not possible then let me know....There may be a cheaper source near me.

Good Luck.........John

84CJ7

Here's what I did. I installed a K&N air filter 130000 miles ago, in the original air filter housing. The hose from the PCV valve to the air cleaner I left intact, as the emissions do get vented from the valve cover into the carb, and that's good. But I disconnected the hose that ran from the air filter housing to the back of the valve cover. This is the "intake"; I believe it had a small square filter setup inside the air filter housing. Instead of this small square filter I bought a second K&N filter to fit in the rear grommet in the valve cover, where the disconnected hose would go. This filter is a small cylinder shaped one, about 2" tall by 2" diameter, has I think a 1/2" fitting to make a nice tight fit in the grommet. Now it don't get oil blowback into the air filter housing. Any oil blowback just gets caught by the small K&N filter. I've had this setup for 15 years with absolutely no problems at all. Fresh air enters the valve cover thru the small filter in the back grommet, and dirty air goes through the PCV valve (front grommet) into the carb. Another hint: change the grommets as they do crumble pieces of rubber into the valve cover. They"re $2.50 each at the parts store.