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Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

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post #1 of (permalink) Old 03-09-2001, 06:31 PM
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I have never posted to the board here, but I have visited it from time to time and found the advice and ideas exchanged here valuable. I am hoping that your knowledge will prove helpful. I have a problem with my 1986 CJ 7. The engine is pretty much stock. I passed my smog test two days ago but they failed me on the visual because the upstream side of the pulse air was disconnected. I put on a new check valve and tube. Most of the emissions went down but the NO actually increased. The problem is in the NO section. Before it was around 900ppm at 15mph and 140ppm at 25mph. Now its 1500 and 1150. The only other variables I can pinpoint were: The first time I may have had some octane boost in the tank(oops). Second that my cooling fans were off the second time.
Welcome to California now pay up.

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post #2 of (permalink) Old 03-12-2001, 01:50 PM
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Re: smog

I hope that this information might help somebody else stranded in CA or other strict emissions states. After the above post I installed a new EGR valve just in case and serviced the air cleaner then went back for another test. The NOx just kept getting worse.(It was over 2000 now) I was ready to give up. That is when it occurred to me about how fuel air mixtures can influence temps and smog. I had a hunch that by reconnecting the pulse air system a lean condition was induced and that by cleaning the K&N a further lean condition was induced. This was aggravated by the fact that I had a fuel regulator installed it was dialed way down due to the rich conditions I was experiencing before. (I read somewhere of a guy with fuel pump trouble having the same condition.) I was at the dealership getting some service on another vehicle and picked the smog guys brain there and he concurred. He also gave me several trouble shooting tips. I went home, removed the fuel pressure regulator, and checked the whole system over one more time.
Monday morning I took the Jeep in and it passed!
Everything seems to have an effect on the smog system not just the smog parts themselves. Remember to check the engine and fuel components as well. Maybe this will save you a little money.

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