MC2100 emissions

88heep · 12-09-2008, 06:00 PM

i am sorry to those that will be annoyed if this has been covered before, but i have done a search and have not really found any help that way. so if anyone can help i would appreciate it.

so here's my problem, i have an 88 wrangler with the 4.2 liter 258. i have upgraded the carb with the MC2100 and its the 1.08 model so its the right carb. i did the nutter bypass and i have the jeep running extremely well. here is my issue, i took it to do the emissions here in Utah where i live and it failed. the low speed test was not that far off and the guy told me they could work with that but the high speen was almnost twice what the standard is. the standard is 220 and it was about 450.

so is there anyone out there thats good with carbs. i don't really know how i can work with the high speed? the only thing i know of is changing the jets, but i have not been able to find anywhere that sells the jets for the MC2100. or does it have something to do with something else. i'm pretty sure everything is set up right, but its just too rich to pass the test.

thanks for all your help in advance.

**4.7stroker** · 12-09-2008, 07:28 PM

I got jets on ebay for around $9 a pair, I believe they are the same as holly jets

Dwayne

jschroder · 12-09-2008, 09:54 PM

I failed miserably with the stock Carter. In AZ our standard for HC is 3.00/ CO is 25.00 and NOX is 4.5. I was at HC 5.83/CO 209.98/NOX 00.13

I purchased a rebuilt MC2100 and installed it and yes I have also heard that the Holly jets are the same. I also did the Nutter at the same time. I decided I wasn't going to take chance on it not passing again so I ran it hard for about 20 minutes to get the Cat heated up and a little denatured alcohol just to be sure and I couldn't believe the difference in numbers. My HC was 1.68, CO was 6.36 and NOX was 2.61. I also love the extra power the MC has.

Mymmars · 12-09-2008, 11:09 PM

88heep, what numbers did you run?

**Alabamaranger** · 12-09-2008, 11:18 PM

I run 46 size jets in my MC2150. Have you checked the size in yours?

88heep · 12-10-2008, 09:29 AM

sorry i haven't reply'd back yet. so i don't know yet what size the jets i'm using are, i bought the kit off ebay with everything to do the install and it was a reman carb and the guy was supposed to jet it right for my elevation. i'll check it out. thats good to hear the jets are the same as the holley, i thought i found some posts from people in my search saying they were different.

anyways i wish i had the my emissions paper with me, but i know my low speed was over but within a passable amount. the high speed was twice what the standard was though so thats where my problem is. i have been thinking of getting some of the denatured alcahol cuase i've heard it works great. i'll have to go pick some of that up.

anyways i'll have to check what my jet size is this weekend, i haven't had anytime with finals on school right now, but i'm just trying to get some good ideas so i can have some direction.

so my question for you guys is do you think the jetting size would affect the high speed enough to make it off by that much?

thanks again, this is really helpful for me.

jschroder · 12-10-2008, 02:00 PM

Did you get the carb from the guy from Colorado that sells them on ebay? That is where I purchased mine and I'm not sure of the jet size but whatever he put in works great for AZ. Did you double check your timing? Is your vacuum advance working properly? What shape is your cat in?

88heep · 12-10-2008, 04:17 PM

Quote:

Originally Posted by jschroder

Did you get the carb from the guy from Colorado that sells them on ebay? That is where I purchased mine and I'm not sure of the jet size but whatever he put in works great for AZ. Did you double check your timing? Is your vacuum advance working properly? What shape is your cat in?

yeah i did get it from the guy in colorado. i haven't done anything with the timing, did you have to adjust your timing after you installed yours? not sure about the shape of my cat, it could be pretty bad though.

jschroder · 12-10-2008, 09:51 PM

Yes I did have to adjust my timing after I installed and nuttered it. I followed his directions for timing and the directions for carb adjustment using a vacuum gauge and it runs awesome. I would definitely check out the cat. My 88 was almost completely clogged when I went to change it out.

Good Luck.

88heep · 12-11-2008, 10:27 AM

alright cool, thanks i'll check those things out and hopefully have some luck.

BigDeaner · 12-11-2008, 11:55 PM

What'de you guys set your timing at?

88heep · 12-12-2008, 09:52 AM

Quote:

Originally Posted by BigDeaner

What'de you guys set your timing at?

good question actually, it would be nice to know that before i go out and mess with it?

jschroder · 12-13-2008, 09:09 PM

I set mine at about 9 degrees at 1600 rpm. That is for AZ altitude. Higher altitude you might want to try 12 degrees so I've heard. Don't forget to unplug your vacuum advance before setting your timing.

88heep · 12-15-2008, 10:00 AM

Quote:

Originally Posted by jschroder

I set mine at about 9 degrees at 1600 rpm. That is for AZ altitude. Higher altitude you might want to try 12 degrees so I've heard. Don't forget to unplug your vacuum advance before setting your timing.

sounds good, hey thanks for your input.