Another emission question
#1
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Ok, I re-tested yesterday and still failed. Arizona requires this:
Loaded HC: 220 (I had 76)
Loaded CO: 1.2 (I had 3.05)
Idle HC 220: ( I had 525)
Idle CO 1.2: (I had 7.0)
So by leaning out the carb I passed the loaded HC test and all numbers came down a bit. I'm not sure how much I can lean the idle/metering rod circuits out. Also, I don't even know if that is the answer.
My question is how do I get Idle numbers down? The loaded test is done driving on the dyno 30-35 MPH. It seems like something else is off causing CO to be this high. Keep in mind all emissions equipment is connected with the exception of EGR.
Loaded HC: 220 (I had 76)
Loaded CO: 1.2 (I had 3.05)
Idle HC 220: ( I had 525)
Idle CO 1.2: (I had 7.0)
So by leaning out the carb I passed the loaded HC test and all numbers came down a bit. I'm not sure how much I can lean the idle/metering rod circuits out. Also, I don't even know if that is the answer.
My question is how do I get Idle numbers down? The loaded test is done driving on the dyno 30-35 MPH. It seems like something else is off causing CO to be this high. Keep in mind all emissions equipment is connected with the exception of EGR.
#2
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Is the cat and AIR pump in good working order? You can lean out the idle mix as much as possible, may have to increase idle speed to prevent stalling. Retard the spark timing slightly and verify the spark plug gap is correct. Also make sure there are no misfires, the air cleaner is clean, and everything in the carb is working properly. The EGR should not affect the CO, but you may want to put it in working order, just in case.
Check this link for more info:
http://www.smogtips.com/failed-high-...onoxide-CO.cfm
Check this link for more info:
http://www.smogtips.com/failed-high-...onoxide-CO.cfm
Last edited by z28pete; 10-10-2010 at 12:03 PM.
#3
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Thanks for the replay. I guess I need to give more information though. It is not the stock motor. It is a 383 stroker with edelbrock aluminum heads, edelbrock air gap intake, edelbrock 1806 carb. Hooker smog headers, with a new working air pump. I re-installed the rochester charcol canister. I have all new exhaust including a magnaflow cat, from the motor back. I have a stand alone distributor (MSB pro billet w/6AL box). The motor has less than 200 miles on it. However it was at the paint and body shop for 14 months being started once or twice a week to go off and on the rack. I pulled a plug yesterday and thought it looked too dark. I'll change them out, I figured that wasn't too big a deal, maybe it is. My biggest fear is that it is just too much cam and that I'll not be able to pass an idle test no matter what. I don't remember the cam specs, but timing is 16 @ base, and 34 @3000. retarding it makes it run like crap. Any other suggestions, I hate to fail a third time...
#4
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I'm having a feeling your problem may be with the overlap of your cam, too bad you don't know the specs. Your high readings could also be caused by oil consumption, but your engine sounds too fresh for it to be that. Back when IL was still testing older cars I couldn't get mine to pass for anything, my idle readings were way high due to the cam. Per the suggestion of the guys at the testing station, I applied for and got a "race car only" exemption. Good thing IL is a state where the left hand doesn't know what the right hand is doing, and nobody follows up or checks. I don't know if your state allows for that, you might want to check.
#5
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i think the main root of the problem is the edelbrock carb. from my experience, they dont have much to offer when it comes to tuning the low end, and generally load up at idle. do you have another carb to switch to?
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