My neighbor is an older gent with a Jeep that's his baby and he can't get to pass smog (California).
He says it's an early 87, "kind of a bastard child in between a CJ and a YJ". It has a new 4.2 liter with a carbureator and distributor (stock I think, he said he'd be willing to replace the carb) that he can't get to pass a smog test. The catalytic converter is only a few years old. He says that he has had guys try to tune it on a smog dyno, and they can get real close to all the parameters passing depending on what they do, but they can't get all of them to pass at the same time.
He wants to do it the "right way" to make sure that it's running like it would have off the lot, which I commend him for, but short of changing the oil and hamfisting around with the distributor and carbureator at the same time while on a 5-gas scanner I wouldn't know how to go about it.
Are there any things on these engines that are notorious for making them a bear to pass a smog? What's the best way to go about it? Would anybody in Southern California be a hot shot with these engines or at tuning older engines to pass a smog test in general? He says he's willing to pay well to get his baby back on the road legally; it's not my area of expertise but I told him I'd look around for him.
CRC makes a product guaranteed to pass the test combined with an oil change,,,I know it works as I have used to get my 1987 YJ to pass twice and I used it in a corvette I owned a couple years ago,,,,,,Give it a try,