any tips or tricks on reducing my emmissions?

[mark]

im desperate at this point.this will be my last shot at it this fri.its a 91 bb chevy in my 76 chero.new wires new plugs dist aircleaner pcv.they only check for hc and co.my closest to passing so far has been hc 229(300 allowable)and 3.22 co(3.0 allowable)
will running the tank almost empty and putting drygas(alcohol) really work?what if i left the aircleaner off?ive done everything but retard the timing but with it this close i didnt know if i should mess with it.
we have to go through a specialty high rise inspection here in nj and it has to pass at the facility.ive gotten it by before but the guys there were always helpful and let me play with the carb right there.but not this yr.if you fail you have to make another appt.i cant loose antmore work and my next day off is in nov.my sticker is good thru oct but they wont let me on base(work)with a failed sticker.

[Jayrodoh]

Drygas worked well for my mildly built 360 without any emissions controls other than a cat. Had to knock the timing back a bit to get it through. Run it up and down the highway and get it real nice and hot before you run it through.

[LouM]

From the readings, it looks like all you have to do is lean out the carburetor. High CO means too rich, the HC is high because of the rich mixture. I'll stick my neck out on a wild guess, if you lean out the idle mixture screws by 1/4 turn (should be clockwise unless you have an oddball holley) and adjust the idle speed it should pass.

Lou

[drlocke]

Based on what you've posted I may be preaching to the choir, but here goes....

Make sure you've just changed your oil before the inspection run. Also make sure you have the hottest thermostat that engine can tolerate. Make sure the idle mixture screws are turned just as lean as the engine can idle without too much faltering.

There are snake-oil remedies that are supposed to enable a car that is on the edge like yours to pass emissions inspection. I've never tried them. The "drygas" trick may well work because there are a lot of hydroxyls (=OH) in the mix when that is added, thus more oxygen present for a cleaner burn.

One time I diddled around under the hood of my '53 Dodge, fulfilled all above listed conditions, and then drove it down to do a voluntary emissions test at a local station. It passed well within margins on both CO and HC. And that's with a low-compression low-tech flathead engine with a tired old Carter BBR1 pisspot on a manifold with a non-functioning heat valve. So this is doable for you, I'm sure.

[TPICherokee]

You could lower your emmissions by buying a Honda.... Sorry I couldn't resist...

[YellowJeep]

A new cheapo 3-way cat would get it to pass too. When in doubt, a fresh cat will clean up even the worst looking emissions numbers. Just remember to drive it about 100 miles to burn off the manufacturing oil!

[AMX factor]

Using good gas about 5 gallons and a gallon of denatured alcohol, new filters, new oil, adjusted a bit lean, if you have a smog pump make sure it's working. Good luck. Experienced the same thing in Denver.

[mark]

thanks for all of the replies.there are no cats i guess thats why they dont check for nox.i didnt think of the oil .ill do that too.i think im gonna try the drygas too.it doesnt seem like it could hurt.

[letank]

the emission is really a dynamic stage... you need to find the values where you almost pass (229 HC and 3.22 for CO)

High CO is uncomplete combustion... so either too much gas or not enough air.... you almost had it... with the air cleaner off

as said.... engine should be really hot.... It is a mistake to turn it off at the emission station.... let it idle.... stay in the vehicle.... emergency brake on, and put in Neutral to circulate the trany fluid..... and right before they let you drive it in ... or they are ready to take over..... rev the engine to 1200 rpm, for 30 seconds.....

and yes the cat will improve emission a lot

forgot.... is yur EGR working?

AND more

What carb do you have on that engine?

I will try to find some good descriptive about the whole HC/CO deal

Here we go from Colorado emission.... gives you an idea

http://www.aircarecolorado.com/repair/fixesfor.htm

Jeep 1982-1991, full size Wagoneer 360 CID, non feedback, carbureted The last of the full size Wagoneers was never fitted with feedback fuel control. This fact, combined with a typical lack of good maintenance, results in this application being one of the highest carbon monoxide (CO) emitters on Colorado's roads. There is no singular fault with this application, rather any one of a combination of the following possible faults has been seen: 1) Weak power valve that opens too easily - poor vacuum to the valve itself
2) Clogged or stuck exhaust gas recirculation valve
3) Worn timing chain
4) Low vacuum as a result of 2) & 3) above
5) Accelerator pump stroke set too long
6) Malfunctioning air injection system - burned out check valves etc.
7) Clogged or burned catalytic converter
Carburetor main jets were usually #56 from the factory, which is too rich for our altitude. As a last resort, the carburetor could be rejetted to #54, #52, or #50 jets. This is a Motorcraft (Ford) carburetor and corresponding part numbers are C3UZ-9533A-54; C3UZ-9533B-52; and C3UZ9533C-50. Particularly when going as lean as 52 or 50, be sure to check for driveability and oxides of nitrogen, as NOx emissions will increase with the enleanment if the EGR system is not functioning.


But do no rejet.... i tried it a sea level and values were worse

[PlasticBoob]

The "drygas" trick may well work because there are a lot of hydroxyls (=OH) in the mix when that is added, thus more oxygen present for a cleaner burn.

Since when is the hydroxyl functional group attached to the chain via a double bond? :confused: :D

[mark]

thanks so much
they have it listed as a 401 6.6 liter
its actually a 8.2 chevy but they dont really care as long as it conforms to the 76 standards.
it was originally tpi but i ditched it when i got it and put a edelbrock performer on it.it has no egr at all(just a block off plate)and im running a holley 670 truck avenger carb.it has passed before but the guy would let me play with the idle screws while it was on the machine.
im thinking with all of the info you guys have provided i can give it a go.

lemme know if any of this doesnt seem right.


1- retard the timing slightly(i have no idea what it is at idle.we set it under load till it just started to ping and then backed off slightly)

2- add 4-5 bottles of drygas to a low tank (1/8th)

3-remove the aircleaner

4- turn the idle screws in just till it stumbles slightly then back off 1/8 of a turn

[AlsChopShop]

why did you pull the TPI from that motor???

Al

[drlocke]

Since when is the hydroxyl functional group attached to the chain via a double bond? :confused: :D :lol: Sorry, old bean! But do pleasr bear in mind that I am not a typist, and the keys do seem sometimes to wander about a bot. Study if you will the common keuboard and you can see where fat sausagr fingees such as mine can sometimes deviate--and hit the = rather than the -....:o :D

May our chemistry knowledge define us
Be we Lucy or Charlie or Linus.
The security blanket
As can one really thank it
Is telling the "=" from "-"!

:D

[andy d]

remove the air filter element. and lower the float level a tad

[Jeep_Guy]

Carb cleaner in the carb and injector cleaner mixed in with the fuel, should clean the carb and jets out pretty well so they can burn fuel as clean and efficiently as possible. Also a x2 on having the engine warm when they emissions test it, if possible. A warm engine will run leaner and reduce your emissions slightly. Dunno about NJ but in PA, if you spend more than $150 on emisssions work, you can get it exempted untill next year. Good luck.

[shimniok]

From the readings, it looks like all you have to do is lean out the carburetor. High CO means too rich, the HC is high because of the rich mixture. I'll stick my neck out on a wild guess, if you lean out the idle mixture screws by 1/4 turn (should be clockwise unless you have an oddball holley) and adjust the idle speed it should pass.

Lou

Agreed. Maybe make sure timing is as advanced as possible without pinging? Ie, optimal timing? Anyone else find that you can kind of trade NOx for HC/CO ? Maybe I am making things up.

I think leaning idle mix screws will help a lot; this was the trick for my 85 when I had it. That even worked on a dyno test.

I have been told to run a can of Seafoam (any auto parts store) thru as instructed; this seemed to prove out for me.

Michael

[PlasticBoob]

:lol: Sorry, old bean! But do pleasr bear in mind that I am not a typist,...
Ahh, just giving you a hard time! :D http://home.off-road.com/%7Eplasticboob/faces/chairfall.gifBTW where's your gif avatar? I was looking forward to seeing it!

Johnny was a chemist's son, but Johnny is no more. For what he thought was H2O, was H2SO4!

[shimniok]

Johnny was a chemist's son, but Johnny is no more. For what he thought was H2O, was H2SO4!

It scares me greatly that I got that joke...

Michael

[imiceman44]

thanks so much
they have it listed as a 401 6.6 liter
its actually a 8.2 chevy but they dont really care as long as it conforms to the 76 standards.
it was originally tpi but i ditched it when i got it and put a edelbrock performer on it.it has no egr at all(just a block off plate)and im running a holley 670 truck avenger carb.it has passed before but the guy would let me play with the idle screws while it was on the machine.
im thinking with all of the info you guys have provided i can give it a go.

lemme know if any of this doesnt seem right.


1- retard the timing slightly(i have no idea what it is at idle.we set it under load till it just started to ping and then backed off slightly)

2- add 4-5 bottles of drygas to a low tank (1/8th)

3-remove the aircleaner

4- turn the idle screws in just till it stumbles slightly then back off 1/8 of a turn

Not the idle screw, the mixture, you need to lean out your mix, CO as was said is a rich mixture, and you have it so easy, if all I had to do was that to pass my K5 I would be done already.
Here they don;t care if you pass the sniffer, they want to see the right equipment :banghead:
It pisses me off that they are not really after cleanning up the air, just having it their way.
:mad:
Good luck with the smog check :thumbsup:

Oh and the HC will drop both from a fresh oil change and from a leaner mixture.

[drlocke]

Ahh, just giving you a hard time! :D http://home.off-road.com/%7Eplasticboob/faces/chairfall.gifBTW where's your gif avatar? I was looking forward to seeing it!

Johnny was a chemist's son, but Johnny is no more. For what he thought was H2O, was H2SO4!

Classic little dittty! As for the gif avatar I've downloaded Gimp2 to create one but haven't had much time to fiddle with it. I look forward to giving it a go when things calm down a bit. Between doing repairs to the coal chute here along with other winterizing, and helping a buddy build a garage in a town 25 miles from me....yep, been busy. :D

[letank]

thanks so much
they have it listed as a 401 6.6 liter
its actually a 8.2 chevy but they dont really care as long as it conforms to the 76 standards.
it was originally tpi but i ditched it when i got it and put a edelbrock performer on it.it has no egr at all(just a block off plate)and im running a holley 670 truck avenger carb.
1- retard the timing slightly(i have no idea what it is at idle.we set it under load till it just started to ping and then backed off slightly)


May be time to invest in a $40 Timing gun... or borrow one. Timing will greatly change your emission, higher advance generates more HC and CO, in my case it was a big drop when i lowered from 12 to 5 (Calif. specs are 5deg. for the 360 CID for 1974).

Also your are tested on a 6.6 liter and you have an 8.2..... so the emissions are a lot higher for the 8.2. I don't know if they would enter 8.2 instead of a 6.6 engine....

Which standard testing are they using.... IM 240....or ?

found this descriptive

http://www.aa1car.com/library/2000/ic60032.htm

here is a little excerpt -saving bandwidth-

Elevated hydrocarbon (HC) emissions usually indicate ignition misfire due to fouled spark plugs or a bad plug. But high HC emissions can also be caused by burned exhaust valves (check compression), lean misfire (check for vacuum leaks, low fuel pressure or dirty injectors), or rich fuel conditions (fuel saturated carburetor floats, excessive fuel pressure, leaky injectors or a dead O2 sensor).
High carbon monoxide (CO) emissions are a telltale sign of a rich fuel mixture. On older carbureted vehicles, fuel-saturated plastic floats, incorrect float settings, leaky power valves and misadjusted chokes are often responsible for the rich mixture. On newer vehicles with feedback fuel controls and fuel injection, leaky injectors, excessive fuel pressure and sluggish or contaminated O2 sensors are all possibilities to investigate.


I think that we have it covered

[mark]

thanks so much!
changed the oil last night and ill be doing the other things shortly.ill have about a 1/4 tank of high test tomorrow morning and ill add the alcohol just before i get there.ive also gotta put my mudflaps back on.my engine always goes right up to 195-200 and stays there so i think its running hot enough without changing the thermostat.

ill letcha know how it goes

[mark]

all done except the dry gas in the am.i would just like to confirm one thing though.if the co is hi and the hc is low if i turn the mixture screws in it should drop the co and raise the hc ....correct?if i fail the 1st time i can prolly play with the idle mixture screws and try again.

thanks again for all of the valuable info!

ps they can only enter 6.6 because it was the biggest engine available for my rig.but i would think that a 91 engine should run more efficient than a 76.although i could be wrong.

[mark]

this is the engine i have.its the one on the top left.most people ask me if its the 502 or 572 hp model but dont understand there was also a 502 designed to take the place of tired 454s in tow rigs.this engine is no screamer but its got plenty of low end tourque.because i drive my rig on the street every day i opted to only run 410 gearing.this seems like quite a mismatch with 42 in tires but this engine just takes it in stride with all of the low end torque.look at the tiny peanut port heads.http://paceperformance.com/paceperformance/2007virtualcatalog/z/00027.jpg

[mark]

THANKS TO ALL OF YOU!!!!!!!!!!!!!!!

passed with flying colors this morning.

hc 300 acceptable came in at 103
c0 3.0 acceptable came in at 2.09

i was quite worried because i got the same guy that failed me last time and he always seems to have a chip on his shoulder.
these are amazing numbers to me.i dont know what the main contributing factor was but i think it may have been adding 5 pints of drygas to 1/8 of a tank of high test on my way there this morning.it seemed to run fine with all of that alcohol added but i had to turn it off at the end so he could put the stickers on.(he actually asked me to do it because it is way too high for him to get in)and i had a little bit of a hard time starting it again.but it did fire up and i went right to sunoco to fill er up.

[shimniok]

Congrats!! It is always a pain with these rube goldberg emission systems & antique carburetors... mine is coming due next year I think... :eek:

THANKS TO ALL OF YOU!!!!!!!!!!!!!!!

passed with flying colors this morning.

hc 300 acceptable came in at 103
c0 3.0 acceptable came in at 2.09

i was quite worried because i got the same guy that failed me last time and he always seems to have a chip on his shoulder.
these are amazing numbers to me.i dont know what the main contributing factor was but i think it may have been adding 5 pints of drygas to 1/8 of a tank of high test on my way there this morning.it seemed to run fine with all of that alcohol added but i had to turn it off at the end so he could put the stickers on.(he actually asked me to do it because it is way too high for him to get in)and i had a little bit of a hard time starting it again.but it did fire up and i went right to sunoco to fill er up.

[mark]

i cant believe its been 2 yrs since i posted this!
im going thru the same thing again right now!

[Daddio]

Do they sell E85 anywhere near you?
It should accomplish the same results, but only use a gallon or two.

[Jeep-Jeep]

.they only check for hc and co.my closest to passing so far has been hc 229(300 allowable)and 3.22 co(3.0 allowable)

I just had mine done for the first time ever, and my readings:

HC-764 (Limit-220)
CO-2.68 (Limit-1.2)

Needless to say, I got a big fat fail!!! LOL:thumbsup:

[smogdredd]

A new cheapo 3-way cat would get it to pass too. When in doubt, a fresh cat will clean up even the worst looking emissions numbers. Just remember to drive it about 100 miles to burn off the manufacturing oil!Yeah, what He said! Basically what You have is the worst possible setup for emissions. If the BB Chevy produced power in proportion to the heat and fuel economy it would be terrifying to drive. When i was doing smog the last thing I ever wanted to see was a late big block anything with a carburetor. They are all awful. The dodge 440 was the best of them when You could get the thermocrud to play nice. If Youre state allows it go with the cat and have it put on flanges for easy removal. Also if You have even a mild cam You'll never get it to go without the cat.

[robwymer]

Buy a 1967 or earlier parts truck, swap the fenders and VIN plate, and voila!!! Emissions test passed with flying colors!

[Showngo]

I had the same problem w/my 90 after the upgrades I put two bottles of rubbing alcohol in it backed the timing of a couple of degrees,unhooked the vac.adv. and leaned the fuel mix about 1/2 a turn.Went through with flying colors.Not even close.