Emissions Woes, need advice!

[TheSeeker]

Hey all, I just finished the mandatory emissions test for my 69 chevy. Its got a 250 with the stock monojet. Carb #7029166 263 8HL.. Anyway I failed the test, the problem isnt with the hydro carbons, they passed a little high but they passed. The CO is super high though. 8 at load 7.2 at idle (percentages) This means im running rich correct? I need to know where to start with this thing as I need it for a daily driver right now. I cant get tags until I pass the test so kind of in a bind.

I dont know if a rebuild kit and a can of seafoam should do it, or if a rejet is in order. or if simply asjusting the carb with a vaccum gauge will take it down enough to pass. The truck was at 190 degrees and the choke was set in the "sweet spot" so to speak. I was planning on putting in an HEI around christmas and the plugs and wires look good but they are old..

Basically AZ emissions laws stink and I need some help to diagnose what is going to reduce the CO the most. Thanks for any leads/ideas/help that comes from this.

[Clyde65]

Why do you need emissions on a 40+ year old vehicle that came with nothing emissions wise really ( I know there is a little bit)

Is it not exempt for the age?

[Dunenutt]

I always had to take mine to a place with a exhaust analyzer and have them set it "for emissions". It will not run set to emissions standards! I would limp it in and pass, then take it home and tune it up! I tried everything, but this is the only way I could pass.

If it's a nice truck, get it insured as classic, get some historic plates, and never see an emissions bay again.

In maricopa county, AZ, it's 67 and older that are exempt from emissions testing

[Clyde65]

oh man! I am glad I live in Texas. they will pass it as long as you can see 10 feet through the smoke cloud behind it.

[SS Tim]

If I may, there is no "magic bullet" that works in every case. To pass emissions your engine needs to be in good mechanical condition and in tune. Start with the basics, a tune (including timing) with filters and oil change are basic to passing a smog test. This site should help some to work through it beyond that.
http://www.aa1car.com/library/2000/ic60032.htm

From your post "Couple of ?? for Weekend projects" it would seem to have been setting a while and not a dd that simply failed in normal use. What does your fuel and tank look like? Did you dump any cleaners into the fuel that are still there? If it was setting long, did you clean the carb and check the floats? Was it down for an engine problem before?

ADEQ's emission testing page has a lot of information that may be of some help as well. It appears that your truck has to only pass both idle and a constant speed tailpipe test. What are your limits vs as measured ppm for HC, CO and NOX?
http://www.azdeq.gov/environ/air/vei/

Also apparently there is a collectible vehicle provision that is triggered through your insurance classification. Worth looking into this as well.
http://www.azdeq.gov/environ/air/vei/motor.html

[TheSeeker]

To awsner some questions..

Yes, This truck belonged to my Dad who would drive it everyday to work for a few years, after my grandfather passed it to him. Since retiring the truck as a driver in 2000. he has kept it in "running" shape and made sure to drive it once a week to the drug store and back. Its in nice shape cosmeticaly, and starts everytime you hit the key but it is running rich. since taking possesion of it about a month ago, I went through basic repairs, (brakes, tires, filters, oil change, etc.) rebuild the shifter linkage and adjusted the clutch. Through my negelct, and the fact that it always started and ran strong, I didnt change anything in the carb. I replaced the fuel sender and cleaned the inside of the tank best I could and changed one fuel filter. I just bought a rebuild kit a float and a can of seafoam.

I figure tomorrow morning ill tear it down, clean the carb, change the fuel filter and run the sea foam through there. In a week when the gas is gone, ill fill up and try again. Im having my uncle-in-law dial everything in after the carb is done tomorrow. And for good measure ill put new plugs and wires and cap/rotor in now. HEI will wait till later. Adjust timing and go for the retest. If it fails, ill put classic insurance on it figure it out from there. Just wondering if there is one area over another that would be causing rich fuel mixture at load (i.e a rejet or just a good clean and rebuild) Thanks!

[69gmc292]

I have never had any problems on passing emissions in Pima County with my truck. I remember that my truck would run a little rich when my choke was just a little closed. I rebent the choke arm and that fix my running rich issue. Also check the float height of the carburetor. I set my to the specs in the book and that caused it to run rich too also when you rebuild your carburetor buy a new float. These old one lung sixes are really hard to get running right but when they are tuned right the purr like a kitten.

[domeier]

High CO means it's rich, (or you know, "rich" by whatever their goofy standard is.) You can lean it with the idle mixture screw, but that only affects mixture at idle - it won't affect the load portion of the test if that's done at a higher rpm(?). Dirty air filter would cause rich; maybe run without a filter for the retest?

[TheSeeker]

good tips guys. I just got back from napa with a box full of goodies for tomorrow morning. Im pretty sure the choke has something to do with the problem. The cable likes to stick a little and it never fully opens/closes all the way. (wife pointed that out tonight haha)

[PanelDeland]

Originally Posted by TheSeeker

good tips guys. I just got back from napa with a box full of goodies for tomorrow morning. Im pretty sure the choke has something to do with the problem. The cable likes to stick a little and it never fully opens/closes all the way. (wife pointed that out tonight haha)

Take the cable loose at the Carb and raise it up.Spray some Lock-eaze or other Graphite lube down it and work it back a forth to free up the cable a bit.I did mine and it works much smoother.

[slikside]

First of all, I can't believe that there is yet ANOTHER state that requires emissions on these trucks...few months back, a guy from Utah was having trouble. But being from Calif., and still living here, it's hard to believe that some states require it when Calif. doesn't...environmental capital of the world and all (I better not let Gov. Brown here me!)

I figure tomorrow morning ill tear it down, clean the carb, change the fuel filter and run the sea foam through there. In a week when the gas is gone, ill fill up and try again. Im having my uncle-in-law dial everything in after the carb is done tomorrow. And for good measure ill put new plugs and wires and cap/rotor in now. HEI will wait till later. Adjust timing and go for the retest. If it fails, ill put classic insurance on it figure it out from there. Just wondering if there is one area over another that would be causing rich fuel mixture at load (i.e a rejet or just a good clean and rebuild) Thanks![/QUOTE]

Try putting premium/higher octain fuel in it...prolly burn cleaner. You don't have to fill it up, just enough....you know?

[70jnktrk]

In Arizona...speciality/classic car insurance...no emissions in Pima or Maricopa County....otherwise...anything 67 and newer in the above counties gets checked..

[domeier]

I remember when I was stationed at Puke AFB in the 80's, I even had to run my motorcycle through the smog station. NONE SHALL PASS!

If there's one "good" thing about AZ smog though, it's that the stations are drive-through, and they're run by the guvmint. In Cal, the inspections are done by third party rapists, who tend to "adjust" their pricing depending upon the gender of the testee. Ripoffs and scammers are everywhere. It's hard to find a good, honest smog dude.

[Dunenutt]

The last time I was in Wickenburg, they still had real gas at the station going north to vegas. No alcohol in it!!! My ol ferd loved it.

May want to make a road trip!

[1972RedNeck]

Here in Montana the FIRST thing you do to a new vehicle is remove the catalytic converter and all other smog equipment.

[oldgold70c10]

Originally Posted by 1972RedNeck

Here in Montana the FIRST thing you do to a new vehicle is remove the catalytic converter and all other smog equipment.

I'll second that! Here in OK, no testing, no inspections.

[MagmaJct]

I'm one of the few out there who doesn't mind emissions testing. A well running engine lasts longer and produces less emissions. Emissions testing is like a checkup so I know my engines are running their best.

As far as California, I hated living there with my older vehicle (VW Super Beetle). Emissions (Smog) shops were run by arse holes. They were ALL afraid to work on my car, whether it would be to adjust the idle mixture, or even touch it! You'd think my car contained the black plague!

In Arizona, they test it no matter what. But if you fail, going to the lobby like they instruct you to do it a waste of time. They have NO CLUE what high CO, or HC even mean! They are all drones.

High HC is too rich. Why is it too rich? Could be low compression, but as mentioned already, there is no "one thing" that is the cause every time. If it's leaned down, will it still idle at the correct speed or does it start to misfire?

Often times in my experience, the mixture is richened up to compensate for a problem, thus is becomes a symptom that masks the root cause.

[special-K]

^ I've always managed to keep my vehicles running tip-top since way before emissions testing ever existed. I think it's pathetic that any state requires a vehicle pre-75 to be tested. The federal gov't hadn't even mandated catalytic convertors till then.
I don't even know what Maryland's laws are. I have never owned a vehicle that had to be tested. I have always either run '72 0r earlier gas powered vehicles,motorcycles,or diesel trucks...all are exempt in the regulation loving state of Maryland. My x-wife drove newer vehicles that always passed no problem. If they ever failed I figured I'd dump racing fuel in just to get it past,then address the issue. I just see it as a money making regulation to get past.

[oldspowered67C10]

Ive been doing smog tests and doing emissions repairs for a few years now so heres the breakdown on the typical gases measured during a TSI(two speed idle) style emissions check. A TSI consists of measuring emissions at idle and at a higher rpm(usually around 2500 rpm) with no load. There are other gases measured in a loaded(dyno) style emissions check but I doubt that's what you're doing so we will ignore those.

CO is a measure of mixture(rich/lean), the higher the CO, the richer the mixture.

HC is unburned fuel, caused by misfires, poor fuel atomization and tends to increase when the mixture goes far above or below ideal mixture(really rich or really lean).

You said that it failed CO so I would first try to set the idle mixture and make sure the choke is opening up all the way when warm. Get the engine warm and let it idle. Look at the choke plate, is it close to or all the way open(parallel to air flow)? If not fix that first. Then check the idle mixture, turn the mixture screw (usually clock-wise)in until the engine starts to drop in rpms ever so slightly then turn the screw out around half a turn. That's a good way to set idle mixture w/o having a gas analyzer to read the gases directly. If you find that the mixture screw is turned in quite a bit more than it was when you started most likely the idle mixture was set too rich.

If you find that both those things aren't the problem then its most likely time for a carb teardown/inspection/rebuild.

Good luck

[QKENUF4U]

Originally Posted by oldspowered67C10

Ive been doing smog tests and doing emissions repairs for a few years now so heres the breakdown on the typical gases measured during a TSI(two speed idle) style emissions check. A TSI consists of measuring emissions at idle and at a higher rpm(usually around 2500 rpm) with no load. There are other gases measured in a loaded(dyno) style emissions check but I doubt that's what you're doing so we will ignore those.

CO is a measure of mixture(rich/lean), the higher the CO, the richer the mixture.

HC is unburned fuel, caused by misfires, poor fuel atomization and tends to increase when the mixture goes far above or below ideal mixture(really rich or really lean).

You said that it failed CO so I would first try to set the idle mixture and make sure the choke is opening up all the way when warm. Get the engine warm and let it idle. Look at the choke plate, is it close to or all the way open(parallel to air flow)? If not fix that first. Then check the idle mixture, turn the mixture screw (usually clock-wise)in until the engine starts to drop in rpms ever so slightly then turn the screw out around half a turn. That's a good way to set idle mixture w/o having a gas analyzer to read the gases directly. If you find that the mixture screw is turned in quite a bit more than it was when you started most likely the idle mixture was set too rich.

If you find that both those things aren't the problem then its most likely time for a carb teardown/inspection/rebuild.

Good luck

GOOD POSTING !! .....

[MagmaJct]

special-k,

I understand the frustrations you have government mandated emissions testing. I too am often frustrated government entities. Whether it be Arizona's MVD, California's DMV, California's "smog check" where shops go unregulated (picking and choosing what cars they test and whether they will perform work on them to get them to pass).

However, Arizona's ADEQ is one of the few government entities that doesn't do much more than stick a pipe up the tailpipe and run the vehicle on a dyno. They will never turn you down, and they will do their job. Compared to other government entities, the wait is relatively short.

As far as being able to "tune" an engine for efficient mixture, different people have a different idea of what is "ideal". You my friend, could very well have an ear and nose for it and be able to find the ideal mixture yourself. But most people who claim they can, actually cannot.

I am one of those who cannot. Many times I've thought my engine was running just fine. However, tests would reveal a excessively rich mixture. I had fuel going right through out the tail pipe! (Not in liquid form, of course!)

I'm sure you understand, others may not, excessive fuel not only increases emissions, but it also is detrimental to the reliability of the engine, leading to accelerated wear and tear caused by the excess fuel washing oil from the cylinders and diluting the oil.

Of course, if I could afford to purchase and maintain a two gas analyzer I would, but I can't. Of course, I wish I only had to take my vehicles in once in two years instead of every year!

[SS Tim]

Just wondering.... how did this turn out?