hi guys,

i need some confirmation that too much carbon monoxide does mean that the engine is running too rich. thats the way i remember it but it wouldnt be the first time i was bassackwards.

Thanks in advance

geez guys someone has to be able to tell me

Yes, it means that the engine is running too rich. Do you have an emission certificate to give us the readings from?

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Leo Paugh
Maryland Chevelle Club #017
A.C.E.S.#3731
progress has little to do with speed, but lots to do with direction.
Maryland Chevelle Club (http://www.chevelles.net/mcc/mcc.htm)

High HC would also indicate rich. Maybe your test sheet has that one on it too?

K

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64 2 Door 400SB/TH350 (actually IN the GARAGE now!)
http://users.rcn.com/chevello
"You laugh because I am different. I laugh because you are all the same."
TC Member #1155

Ok here goes,

AZ emissions, 67 malibu w/ stock 283 w/ rochester 2bbl

LOADED READINGS

HC IN PPM 296- MAX 450 PASS

CO IN % 2.28- MAX 3.75 PASS

IDLE READINGS

HC IN PPM 366- MAX 450 PASS

CO IN % 6.56- MAX 5.00 FAIL

My train of thought was to open the idle bleed screws to lean the mixture, check the plugs, and change the oil. What are your thoughts?

Thanks for the help

What was your idle speed, adjusting the idle up a little might help.

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Leo Paugh
Maryland Chevelle Club #017
A.C.E.S.#3731
progress has little to do with speed, but lots to do with direction.
Maryland Chevelle Club (http://www.chevelles.net/mcc/mcc.htm)

Hmmmm, here in NJ, the 70 Chevelle has to adhere to the FEDERAL standards which were in effect on the date of manufacture. HC=700 PPM, CO=2.28%. How can the standards be tighter for a vehicle 4 years older?? In any event, my Chevelle recently (October, 2002) tested 73 PPM and 1.28% respectively, using the "tailpipe" test. Vehicles built before 1981 are subject ONLY to the tailpipe and not the dyno test in NJ. If you turn the idle screws OUT, you are making the mixture RICHER, increasing CO. If you turn them IN, the mixture runs LEAN. Too lean and you could cause misfire. Be sure you have a NEW airfilter in place, the ignition timing correct AND the mixture screws about 1 1/2 turns out. A good starting point. Adjust your timing to factory specs (4 degrees before TDC is it?). Make sure you have new plugs and good wires. Faulty ignition or marginal ignition components CAN cause high CO readings. Change your oil and filter...yes it CAN make a difference in emission readings. I've been doing this for the last 25 years or so of NJ emission testing and have had very little trouble getting through with the Chevelle.

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
597,000 miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

[This message has been edited by MalibuJerry350 (edited 02-01-2003).]

i just realized the way i wrote the results may have been misleading

THIS SET OF NUMBERS IS WHAT MY CAR READ-

LOADED ACTUAL READINGS

HC IN PPM 296

CO IN % 2.28

IDLE ACTUAL READINGS

HC IN PPM 366

CO IN % 6.56

THIS SET OF NUMBERS IS WHAT MY CAR HAS TO BE UNDER-

LOADED LIMITS

HC 450 PPM

CO 3.75 %

IDLE LIMITS

HC 450 PPM

CO 5.00 %


SO- I JUST NEED TO GET THE IDLE CO DOWN WITHOUT RAISING THE OTHER STUFF.

As far as my idle speed, i am not sure exactly (no tach) but i did turn the idle up some before testing because it was idling so well it would just tick over and i figured it would do a bit better higher.

As far as the loaded emissions test- thats f****** arizona for you, 66 has no emissions test, 67 gets what i get, and unlike CA that wont roll, i will always have to get a test.

I'm still questioning the standards that Arizona is imposing. Aren't the Federal Standards "the bible"? Does anyone know what the Federal emission standards were in 1967 for your combo? At any rate, you should not have any problem if the engine is tuned correctly. Make sure your dwell is set correctly also (if using points). Timing AND fuel mixture is very important. Also, we used to remove the air cleaner element right before we entered the inspection facility to bring the CO level down. Be sure your choke is opening completely. Don't idle the car for a long period of time before the inspection, either.

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
597,000 miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

Jerry, Just an FYI from a MD certified emissions inspector, the states use the Federal specs as a guideline and the state can impose stricter specs, esp if in a non attainment area. I looked at the Md specs the other day and for that old of a car, the specs for HC are 700 and CO is 660. Good old Arizona is tough.

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Leo Paugh
Maryland Chevelle Club #017
A.C.E.S.#3731
progress has little to do with speed, but lots to do with direction.
Maryland Chevelle Club (http://www.chevelles.net/mcc/mcc.htm)

Yea i should check the timing to see if its on, its an hei with platinum plugs and 1yr old wires. Would retarding the timing help bring the CO down or is that just for HC?

As far as adjusting the idle mixture would you guys recommend reading the plugs to adjust it?

I will pull out the air cleaner and make sure the choke is off before hand those are good ideas.

Figures i would have just sqeaked under in MD.

Any other ideas are welcomed,

thanks guys

Leo,
I appreciate your answer, however, if a vehicle is built to meet Federal standards for that model year, HOW can the state/county/whatever, mandate stricter standards? We, in NJ, have been going through this since the mid 70's (state wide emission testing with the annual safety inspection, but the Chevelle usually tests WAY below the maximum levels. Also, here's something interesting for Pennsylvania residents. http://www.post-gazette.com/healthscience/20030107inspections0107p1.asp

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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
597,000 miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

[This message has been edited by MalibuJerry350 (edited 02-01-2003).]

Geez, onboard testing.
Watchit there buddy, Big Brother is watching.
I guess I'll keep my CA plates.

Jerry, I thought that the HC reading indicated unburned hydrocarbons in the exhaust. So, rich would be more HC and lean would be less HC (and more NOx). Do I misunderstand or did you mistype?

Keith

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64 2 Door 400SB/TH350
Chevello Page (http://users.rcn.com/chevello)
"You laugh because I am different. I laugh because you are all the same."
TC Member #1155

<BLOCKQUOTE>quote:</font><HR>Originally posted by Chevello:
Geez, onboard testing.
Watchit there buddy, Big Brother is watching.
I guess I'll keep my CA plates.

Jerry, I thought that the HC reading indicated unburned hydrocarbons in the exhaust. So, rich would be more HC and lean would be less HC (and more NOx). Do I misunderstand or did you mistype?

Keith

<HR></BLOCKQUOTE>

Yep...a nice big ol' mistype. http://www.chevelles.com/forum/smile.gif Fingers going faster than the brain! The HC problem can be a result of bad plugs, marginal wires, faulty dwell setting (if points) or cap/rotor. That car, if properly tuned, should go through with very little problems.



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MalibuJerry350
TC Member #1279
Original owner '70 Chevelle.
597,000 miles on car.
Hey, if it's got wheels, DRIVE IT!
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html

You can also get high HC's from lean misfire if the carb is adjusted too lean. As I said before, the Federal guidelines are just that, guidelines and the states have to have some kind of program in place similiar to the Federal, but not the same. Federal highway funds are tied to adherence.

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Leo Paugh
Maryland Chevelle Club #017
A.C.E.S.#3731
progress has little to do with speed, but lots to do with direction.
Maryland Chevelle Club (http://www.chevelles.net/mcc/mcc.htm)

So whats the consensus say?

is my idle rich, lean, or just not running right?

In case anyone reads this looking for answers to a problem similar to mine-

-I raised the idle a bit to about 950, it was actually a little low before even though it ran perfect.

-I adjusted the idle mixture to the lean side of peak vacuum. I was thinking of model airplane engines that have idle bleed air screws when i was talking about opening the idle bleed screws (dont mind me). It doesnt run nearly as well like this, it likes to bog coming off idle if you arent carefull, but-

I took it back to get my free retest and it passed with flying colors, nothing was even close to those limits that are supposed to be tighter than what the federal standards were. thanks guys