High Carbon Monoxide Level

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DSG Duster

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I bought my '75 Duster, slant six, auto last year with 55,000 miles. A condition of the sale was that it would pass emissions, which it easily did, even though it ran somewhat rough. Since then, I've replaced air cleaner, plugs & wires, dist. cap, voltage regulator, alternator, & ballast resistor. I know some of those items have nothing to do with emissions, but still, this is what happened. Every reading on the test I just had done( at 61,000 miles) was lower than when I got the car, except for carbon monoxide at idle. It went from .31% to 5.28% (pass is 4.58%). The car runs great, nice & smooth. It is a completely original car, with all smog equipment, & it had a new carb at 48,000 miles. I don't have an emissions analyzer, but I have just tuned it according to the factory specs, & that makes it run rougher. I just can't understand how the readings could jump so much, when I've improved things. Does anyone have any advice? Thanks, - Dale
 
Knock the timing up a few degrees.
 
Generally your CO(Carbon monoxide) is high when your HC (Hydro Carbons...fuel) is high...Your state everything is lower....I guessing HC are...
We test at 2500 rpm and at idle.I could use all your readings and then tell you how to correct it.
Minimum idle on our test is 1200 rpm....You may be idling too low like 600 rpm...Raise idle to 1000 rpm would help...
Need all the numbers and then can further advice....DO not richen....
 
The last few hotrod's i tuned to get thru Md. emissions in the mid 80's, higher idle and a lot of timing retard was needed, as was said above. Leaning too much made it worse. I know it's probably apples and oranges as far as the required numbers, but the worse they ran the better.....lol.
 
OldmanRick said:
The last few hotrod's i tuned to get thru Md. emissions in the mid 80's, higher idle and a lot of timing retard was needed, as was said above. Leaning too much made it worse. I know it's probably apples and oranges as far as the required numbers, but the worse they ran the better.....lol.
Click to expand...
Agreed on hot rods...I run an emission station in Texas...When one pulls in running like crap,I know they retarded their timing a bunch and many re adjust in the parking lot after passing as not to over heat...
But with a slant six I think in tune and high idle is the trick...
 
Yeah I was havin a retard moment. Sorry bout that. See my avatar.
 
DSG Duster said:
Emissions testing is due to be discontinued here at the end of 2014, but they will screw me for $23 each year until then!
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emissions? I know of no such thing, push pull or tug your car to the service station, have them look at it and if its not falling apart front end wise, or gapping holes it passes motor vehicle inspection for 2 years, costs about $34
 
we tail pipe from 89-95 and 1996 to new go by OBD11...Check engine light...all other exempt and only in four cities El Paso,Dallas,Austin and Houston....rest of the state safety sticker only....
 
I guess most states will get in our wallets some how. Once Jeb got rid of emissions if FL, i had smooth sailing my last 14/15 yrs there. 5yrs in central VA had yearly safety only and personal property tax.....still sucked :D. Now in SC, no smog, no safety, but still PP tax. I'm happy with it though. At least I don't have to drag any cars in for scrutiny. I just pay the man and go on about my business.....lol.
 
Safety sticker for the window licker that drives a piece of ****. Cause he don't know why it won't go or move a single bit. So fix his crap a big bill he gets slapped and send him on his way. To lick his windows and keep pretending he's not driving a chevrolet.
 
But what does she really wanna lick?
 
TXDart said:
Generally your CO(Carbon monoxide) is high when your HC (Hydro Carbons...fuel) is high...Your state everything is lower....I guessing HC are...
We test at 2500 rpm and at idle.I could use all your readings and then tell you how to correct it.
Minimum idle on our test is 1200 rpm....You may be idling too low like 600 rpm...Raise idle to 1000 rpm would help...
Need all the numbers and then can further advice....DO not richen....
Click to expand...

Here, they test at about 40mph(driving), and at idle. My readings are:
Hydrocarbons 100ppm driving/ 145ppm idle
Carbon monoxide .20percent driving/ 5.28 percent idle(failure)
Oxides of nitrogen 1428ppm driving test only
All readings except carbon monoxide at idle (max 4.58 percent)are less than half of the maximum allowable. Timing is 2 BTDC , idle is 750 RPM.
 
Your HC really not that bad for a carburated vehicle but if we can lower it the CO will follow.
Have you adjusted your valves?
Is the air filter clean?
Is the pcv valve working?
When was the last oil change...dirty oil hold HC and will affect a test....
High HC raise CO
 
You know that if it is not all warmed up it will do worst on the test....make sure your choke flap is wide open.....
 
TXDart said:
Your HC really not that bad for a carburated vehicle but if we can lower it the CO will follow.
Have you adjusted your valves?
Is the air filter clean?
Is the pcv valve working?
When was the last oil change...dirty oil hold HC and will affect a test....
High HC raise CO
Click to expand...

All of the above are good, except for the valve adjustment. My problem is trying to figure out what made the idle CO reading jump up so much in 6000 miles.
Thanks to everyone who's helped so far. - Dale.
 
I adjust the valves,bring the idle up to 1000 rpm for the test and changed the oil and go right back there with it good and warmed up and bet you will pass...Wish you were here with my machine I could fine tune it for you...Good Luck
 
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