258 MPI conversion

I live in California and own an '83 CJ-7 with a stock 258 (52,000 miles) that I'm considering installing a Mopar MPI fuel injection conversion kit on. One of the suppliers I called stated they were no longer recommending these conversion kits (he would gladly sell me a 4.0 liter engine, though) because of subsequent problems passing smog check. He said the 258 cylinder head was not designed for FI and, in order to pass smog (NOx), the timming in converted 258's needed to be advanced to the point where the performance gains from the MPI were negated.

Intuitively, I have trouble with his claims because it seems the improvent in fuel mixing and distribution provided by the MPI can only make the combustion chamber more efficient. And a properly functioning catalytic converter should control NOx emissions.

Are there any California Jeepers out there who have performed this conversion share their smog check experiences? Is there any merit to his claims? Should the MPI conversion also include a 4.0 liter cylinder head and cam? Any feed back is greatly appreciated.

[RiffRaff]

I did the conversion to my 85 CJ7 back in, oh, 98 I think. I have never had any problem passing smog. In fact, the engine has never performed better. The kit was well worth the money and i installed it myself. I only had a slight problem this last time I got it smogged due to the new test they do. I had to take it to the dealer, but it still passed fine. I would say that guy is full of crap and is simply trying to sell an new engine to you as he probably makes more money on those.

I agree with Riff. The MPI kit is basically the same MPI setup on the 94 4.0. The only real difference between the 4.2 and 4.0 (besides .2L) is the head design. The 4.0 breaths a little better. As for timing...there is no timing adjustment. The dist is set in one place and the computer takes care of the rest.

Everyone that I know that did the conversion was happy with it.

However...if I may point out...for the cost of the conversion, you can put in a used 4.0 for the same money or less.....and it won't be that much more work....maybe a day more.

Or, if you really feel like having fun....do a Small Block Chevy conversion with a 5.7L TPI or TBI....

Thanks for the quick responses, guys. You've helped confirm my suspicions. I'll order my MPI kit and damper tomorrow.

Thanks again,

Angus

[RRich]

Yup - sounds like he had some reason to talk you out of it.
He said to pass the NOx test you'd have to advance the timing -- not true, if anything that would drive the NOx HIGHER.

He's full of it.

[thorjeep]

Love mine, had it for ~ 6 years now. Don't take it to a Joe-Bobsmog and gas station, they will red tag you and then it is referee hell. Best call around and make sure they have done this kit before. I don't know where you are in CA, but I reccomend the "The smog station" in Dublin CA (Near SF). Was there Friday and the owner said CA doesn't like the kit too much (Would rather you get rid of the Jeep), and usually requiring referee, but some smog places are cool. Word of warning when you get the kit: Take the stickers gingerly out of the package, and put them safe place, where you cannot lose them! Make a copy of the instructions too, as you will need the original if you need a referee. There are a lot of good write ups on this site and others that help with the install very nicely. And lastly, just take the fenders and front grill off first, it is much easier that way! PM me if you have any questions, I'll try to rack my rusty memory. [img]/ubbthreads/images/graemlins/grin.gif[/img]

[lomodyj]

I'm not in California...But I've been there once or twice. Here is my install