Jeep CJ series 1982+, EGR/Cat System bypass

[Krys Kozlowski]

Perhaps one of the more weird car mods I have seen in the past few years was the removal of the entire EGR/Emissions/Cat system on a 1982+ Jeep CJ series.

In essence, my friend has recently acquired a 1983 Jeep CJ-5 4.2 I6.

This here thing

When we picked it up, it had some amount of knock and was running like crap. The previous owner had put it up for sale with a faulty hence unadjusted carburetor in mind, yet it turned out it was something completely different.

While picking up parts for this antique behemoth, I randomly met a guy who runs the local vintage Jeep fan club. He’s the guy on the right. An experienced mechanic and Jeep connoisseur, he immediately advised me to remove the entire emissions system to get the thing running. So here’s what we did and why:

First, you need to run the engine to a warm status, that is, once the auto choke jumps into the off position:

Sorry for the sucky picture. You will find two adjustable screws next to each other where the circle is. The one closer to the carburetor is the auto choke one, the one closer to you is the regular (warm) idle adjuster.

Once it jumps to the warm idle adjuster screw, turn off the car.

Now, while it’s still hot, follow all the leads and hoses from these two distributors on top of the engine / on the firewall

Remove all wires and hoses, also, do not forget to seal up any openings you leave behind. Now remove the two brackets that hold them altogether, and voila.

That procedure bypasses the controller for the warm up phase and puts it into auto choke mode when starting cold.

Now adjust the carburetor, either by ear, or with an external rpm gauge, to roughly 650 to 700 rpm, and adjust the fuel input on the front with a flathead.

The locations, looking from the front, are roughly:

Adjust the screw until you see or hear the engine rpm start dropping again, turn it back to the maximum point, and do the other one. You’ll have to repeat that a couple of times until it’s perfect.

A word on the emissions bit. Those old catalytic converters were basically quite inefficient by today’s standards, yet the control system was even more pathetic. The car will pass emissions testing in Germany (very strict) even with the system off, and I understand a few guys from California made that happen over there as well. So if you have horrible idle, knock, or an “unadjusted” carb that resists adjustment, try that.

Cheers

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[college man]

Thanks for the tip. 😉

[Eric]

My first ride was a 1982 CJ7. Inline 6-258. So many headaches with it, but I loved every minute of it. Removing the cat, adding headers, and a non stock carb makes a night and day difference!

[Author]

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