Smog disabled 1990 YJ -
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post #1 of 3 Old 02-25-2009, 04:20 PM Thread Starter
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1990 YJ Wrangler 
Join Date: Feb 2009
Location: Nashville, TN
Posts: 54
Smog disabled 1990 YJ

Hey all,
So far I'm enjoying my membership here. Lots of useful info, thanks! Can anyone tell me if a '90 YJ is computer controller or not? This one I bought has had most of it's smog related gear pulled out or disabled, and I'm not sure where to start. I'm considering a new carb/intake manifold/header combination. There are no smog regs where I live. Anyone have any suggestions?

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post #2 of 3 Old 02-25-2009, 04:34 PM
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1996 ZJ 
Join Date: Oct 2006
Location: Vernon, NJ
Posts: 4,758
Take a picture of the carb and engine and post a link. All the 4.2's had a computer controlled emission system. Read all about the workings here..LINK. It can run very nicely with most of the stuff removed.. Search Nutter Bypass....

96 ZJ.
05' Grand Cherokee Limited, 2"OME lift
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post #3 of 3 Old 02-25-2009, 04:35 PM
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2008 JK Wrangler 
Join Date: Mar 2007
Location: Arizona
Posts: 1,127
As long as you are positive that you have no emissions restrictions you can rip it all off. This is a very popular topic here on YJ - JF. But if you ever move or sell it in another state you may find that you can't get it registered an almost everything has to be put back on.

Do a search for "Emissions YJ? you will find dozens of threads.

As far as computer controlled... yes you have it on a 1990 but you can all but eliminate it by doing the "Nutter bypass" If you have a stock Carter Carb there are a few extra steps related to modding the carb, any other aftermarket Carb and the Nutter is a must do.

The biggest pitfall to removing all the stuff is vacuum leaks. Pay close attention to the details.

One does not establish a dictatorship in order to safeguard a revolution; one makes a revolution in order to establish a dictatorship. - Orwell
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