Failed Emissions Test, where do I start?

[243]

79 Wagoneer with a 76 401, rebuilt 4bbl, no smog pump, charcoal canister not hooked up, egr not hooked up and no catcon. New secondary ignition components with the exception of spark plugs.

I replaced the spark plugs this afternoon with ac/delco gapped at .045. It is still a little rough at idle but it helped mid and top end quite a bit. I'm looking for vacuum leaks now.

Will pass safety after fixing an exhaust gasket leak and adding the hose from the air cleaner snout to the radiator core support.

fixed both of these items plus the radiator crack courtesy of JB this afternoon

High Speed

HC 29 (Standard 600) Pass
CO% .08 (Standard 6.0) Pass
CO2% 13.1
O2% 2.7
Dilution % 13.2 (Standard >6.0) Pass

Low Speed

HC 799 (Standard 600) Fail
CO% 2.57 (Standard 6.0) Pass
CO2% 9.9
O2% 4.6
Dilution % 12.5 (Standard >6.0) Pass

I read through the emission threads and both timing and idle mixture could be the problem.

I need help because this is going to be my daily driver (65mi roundtrip) starting Monday. Any other suggestions would be greatly appreciated!

Which direction "leans" the idle circuit, needle in or out?

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243

79 Wagoneer 401/T400/QT
76 Wagoneer (parts car)
99 Dodge Ram TD

cummins_isb@hotmail.com



[This message has been edited by 243 (edited May 09, 2001).]

[243]

C'mon guy's, I need your help on this one.

243

[mahlmann]

I'm surprised there's no NOX test like we have in California. You didn't mention why you didn't change the plugs, but if just one of them isn't firing 100%, you won't pass. But, you are pretty darn close. My suggestions would be:
1. Use new plugs gapped a little on the wide side (based on what ignition system you're running. With an MSD box, I'm running .050")
2. Make sure your engine is FULLY warmed up when you get it retested.
3. Run your gas tank down to "not much left" and pour in a couple of bottles of isopropyl-based gas dryer. Then, after the test, fill up with what ever you usually run.

As close as you are, this should get you where you need to be. Let me know how the retest goes.

Good luck with it.

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Mike Ahlmann
'87 Grand Wagoneer
"Steel Brick"
Sunnyvale, California

[243]

Mike,

I picked up plugs this afternoon, I think there is a little miss because the engine shakes just a bit. I had not changed them because I've been working on other "bugs".

I should be down to 5-7 gallons right now.

What is a "isopropyl-based gas dryer"?

243

[This message has been edited by 243 (edited May 09, 2001).]

[andy d]

dry gas, methanol will work too, i use a 12oz. bottle per gal. takin out the aircleaner wont hurt.

[243]

The air cleaner was out during the test.

Can the egr valve be the source of a vacuum leak?

243

[Matt W]

<BLOCKQUOTE>quote:</font><HR>Originally posted by 243:

Which direction "leans" the idle circuit, needle in or out?

[/B]<HR></BLOCKQUOTE>

is this the motorcraft 4bbl still? screw them all the way in and count how many turns it takes.you should see black smoke pour out the exhaust when you rev it up in park. if it stalls, thats even better! then pull a plug and see if its wet. now that you know which way is rich, go the other way, I wish i could be more help , but i have no idea if they made those motorcraft carbs with reverse idle mixture screws or not! i don't think they did in 78or below, but my 79 manual says clockwise all the way in is full rich, so who knows? I hope this helps. you could also try adjusting your initial timing to smooth it out, or the choke could be out of adjustment, the exhaust manifold heat valve may be stuck? its the thing down on the pass side manifold, it should move freely open and then spring shut.the spring, i believe, heats up and opens it when engine is warmed up like a choke spring. you could check your idle speed adjustment screw, its on the throttle linkage on the carb near the back of the linkage. i would say after you've tried this, cheat. just make sure your engine is warmed up when you go, and try hooking up your charcoal can to the various lines. it really should be hooked up to the fuel tank at least., before you hook it up, blow out the lines that will go to the distributer and the carb. ALL of the 5 jeeps that me or my dad own have no egr valve anymore! all the diagrams i have are for a 2 bbl engine, but they show the line coming from the egr(1 vac fitting) goes to the top of the egr cto switch on the front corner (either corner, i guess, as long as it only has two ports coming off the switch) of the intake. the bottom or second port on the egr cto switch runs back to the carb base on the drivers side front corner,and indicates ported vacuum. hope this gets you legal! http://www.ifsja.org/ubb/smile.gif I really don't know if these intakes are meant to run well if the junk is pulled off of them...my 77 360 4bbl didn't/doesn't, looks like it may be getting an edelbrock intake in the not too distant future!...diesels=stinky. http://www.ifsja.org/ubb/biggrin.gif

[Dave _S]

With your high HC emissions you may have hook up the smog pump and the cat. All the pump does is inject air (read extra oxygen) into either the manifolds or the cat. Not sure what the setup is on a '79. The extra air helps burn any unburned hydrocarbons remaining in the exhaust. It sounds like where you live you don't have a visual check, however, if you have to meet '79 emissions standards for catalyst equipped vehicles you will probably at least need the cat. Unless the Texas standards are very loose, then maybe you could get away without it.

[This message has been edited by Dave _S (edited May 10, 2001).]

[rhinoherd]

Drive up to Crockett to a local inspection station and tell them you just moved to town/or near town. Get it inspected and don't worry with that stuff.

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Rhinoherd: Gladiators-
64 400 Chev/60/44/700R;
66 454 Chev/60/44/T18a;
67 327/44/44/TH400;
68 327/44/44/3on tree
70 350/44/44/TH400;
71 350/44/44/T18a/PTO Ramsey from factory;
73CJ5/258/200HP/T18/44/30/Rancho all under

[243]

I've been thinking about that route.

I have two neighboring counties I can try before I resort to a day trip.

243

[Matt W]

btw, the air pump doesn't actually do anything except ADD more ppm to your o2 reading, making your contaminants read smaller ppm wise. you cant burn exhaust twice.