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-   -   Need help passing smog with my 1990 jeep w/ carb (http://www.jeepforum.com/forum/f262/need-help-passing-smog-my-1990-jeep-w-carb-1369174/)

BobbyJoe619 05-14-2012 11:29 PM

Need help passing smog with my 1990 jeep w/ carb
 
I own a 1990 jeep wrangler 4.2 L. 6 cyl. Manual w/ carburetor and it won't pass smog. It is registered in San Diego California, had no problems passing in 2011 and everything has been kept stock. I failed evap test, gas cap failed, and failed emissions because NOX is too high at 15. mph. ( max. is 714 my MEAS is 960). My CO% read MEAS 0.00 (max 0.52 ave. 0.10) At 25 mph everything is fine and has a pass. Any suggestions?! Please help!:(

jbolty 05-14-2012 11:43 PM

high nox is generally caused by a bad cat, bad EGR or a too lean condition with overly high combustion temps.

The 4.2 is notorious for vacuum leaks so start with that.

Take off the egr, clean it and make sure it's moving freely.

See if the fuel vent system is all solid and pay attention to the rollover valve up inside the right rear fender.

Go here for a hose diagram and other info.

http://home.sprynet.com/~dale02/list.htm

Delta347 05-15-2012 12:00 AM

Quote:

Originally Posted by BobbyJoe619 (Post 13569551)
I own a 1990 jeep wrangler 4.2 L. 6 cyl. Manual w/ carburetor and it won't pass smog. It is registered in San Diego California, had no problems passing in 2011 and everything has been kept stock. I failed evap test, gas cap failed, and failed emissions because NOX is too high at 15. mph. ( max. is 714 my MEAS is 960). My CO% read MEAS 0.00 (max 0.52 ave. 0.10) At 25 mph everything is fine and has a pass. Any suggestions?! Please help!:(

Had that issue on my 90' Auto 4.2.....I paid like 800$ for repairs and checks...then had it smogged and it went from 1148ppm to 2600ppm.....

I tried cleaning the EGR which made it worse, I tried checking the vacuum tubes but just kept finding more and more that were dsiconnected that I couldnt figure out where they were supposed to go.

Check your Catalytic's 'return' pipes it turned out both of mine were completley rotted through and not even doing anything..and check the Cat mine got water in it through the rotted holes in those 'return' pipes (the narrow ones that go back to the manifold and air box) and ate the entire inside out....

BobbyJoe619 05-15-2012 02:04 AM

Thank you guys for the suggestions, they are very helpful. Now I know what to do with my Jeep first thing in the morning. It doesn't surprise me at all that the guys at Harloff ( Gold Shield certified smog repair shop) didn't have any other suggestions besides throwing out the carb and installing a Howell fuel injection kit! They made it seem like no one will work on carburators anymore.

jbolty 05-15-2012 07:30 AM

If you have the money for a howell kit do it immediately.

BobbyJoe619 05-15-2012 10:49 AM

Ok is there a good place where I can buy a used Howell kit that is in excellent condition? If I get a brand new one and have Harloff install it with 10 man hours it will cost me around $2,200!

jbolty 05-15-2012 10:56 AM

Kits pop up on craigslist once in a great while and sometimes on ebay. Personally I would get it direct from Howell for the warranty and support and do it yourself. Best mod I ever did.

The other alternative is to swap in a 4.0 with fuel injection.

Sounds like you can get the smog passed if it's only high nox.

Xpress 05-15-2012 12:06 PM

Get the Howell kit and put it in yourself. You have to learn how to work on your own Jeep, because these are high maintenance toys. None of that maintenance free stuff, and that's what makes them such a fun hobby ;)

BobbyJoe619 05-15-2012 01:15 PM

cool. I am going to run the Jeep through the diagnostic phase first at Harloff tomorrow to check everything before ordering the FI just in case.

jbolty 05-15-2012 01:29 PM

Before you do anything or spend any money on an FI kit make sure the engine is otherwise in good order. Good compression, no excessive oil use, no cooling problems, etc.

BobbyJoe619 05-15-2012 01:30 PM

Also I will admit that I am a rook and it will be a bad mistake if I try to do this myself

BobbyJoe619 05-15-2012 01:32 PM

Thanks jbolty just what I had in mind!

StvDiego 05-15-2012 10:53 PM

Quote:

Originally Posted by BobbyJoe619 (Post 13571389)
Ok is there a good place where I can buy a used Howell kit that is in excellent condition? If I get a brand new one and have Harloff install it with 10 man hours it will cost me around $2,200!

A problem with buying a used Howell is that getting support for CARB issues from Howell (and getting a CARB sticker) becomes much more difficult.

i wouldn't worry about the install as a DIY, if Jeff (jbolty) can do it anyone can :p

jbolty 05-15-2012 10:59 PM

nothing to it

http://i3.photobucket.com/albums/y95...l/HPIM0338.jpg

StvDiego 05-15-2012 11:57 PM

cut the green wire

or is it the blue??


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