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Holley 5200 idles good but smog no.s are

873 views 5 replies 2 participants last post by  sqzbox 
#1 ·
Right now it's idling at around 1100-1200 rpm.I've gotten the air-fuel screw down to where a vac. gauge needle stays very still,but i get a reading of HC 184ppm .I also got 1.57% for CO. NO ppm was 103,according to a smog machine.It does have a good cat.The idle screw is backed out all the way.What else can i do to lower the rpm's? The engine is a 22r in a 86 toyota truck.The engine has the 5200,header,Jacobs,no smog equipment hooked up.Can i also lower the fuel level to see if that helps,or do i need to drill those tiny holes on the throttle blades?
 
#4 ·
you could and it might help only if the float is set too high at the present.
Have you double checked for vacuum leaks? A big one like the size of the PVC valve could raise your idle speed and, adj. the air fuel ratio would have no effect. Same goes with the idle speed screw, you could back it all the way out and still not get the rpm down enough.
Another thing to look at is down the carb. Look and see if the throttle blades are all the way closed or open just a fraction. If they aren't, something is causing them to not to close all the way and that would take the carb. off the idle circuit.
Just some Idea's to look at. Hope it helps. :cool:
 
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