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emissions

T

t's85chevyk5

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I have an 85 k5 with a carbuerated 305. Every thing dealing with the motor has been kept to the stock setup. I recently changed my egr valve but i still failed on my NOx levels. Every thing else is very low. does any body have an idea of what the exact problem is or what it would need to pass? My vehicle s emissions on nox levels were 7.42. The amount allowed is 7.00

thanks fellas
 
i hear 20 bucks helps you pass. LOL we dont have emissions checks here in florida.. i remember hearing about "drygas" to lower one of the emissions..
 
What timing set at? Did you adjust carb? I have ran mine through emissions in Maricopa County twice and passed with less than the half the allotted amounts . I don't have too much time this week but I am sure if you could make it to Mesa I could look at it with ya. I basically run stock setup also, with a little hose cleanup underhood.
 
my dads buddy is going to put the sniffer on it today. Maybe he could figure it out. I was just wondering if anybody had simmilar problems. I appriciate you trying to help, but i cant make it to mesa this week because of work and school. /forums/images/graemlins/waytogo.gif
 
theres not much you can adjust on 80s smogger carbs cept for idle speeds and choke, the mixture screws are sealed and you arent supposed to touch them
do you still have EST Q jet and HEI setup intact ?


good luck
 
Well NOx is caused by heat, and heat when the EGR valve doesnt open. You said youve replaced it, check everyhting before the EGR, and make sure its opening up, when it does the NOx should drop off!
 
This is an interesting thread and hits right at home with me too. I ran my 1985 K5 through emissions two weeks ago and failed it due to a excessively high carbon monoxide reading.

I guarantee it's the first time this truck has ever been through an emissions test since it rolled off the factory floor, and God only knows if the AIR pump still works or not. /forums/images/graemlins/grin.gif

Anyone want to take a stab at why it's got such a high CO reading? I'm going to either have to pour some isopropyl alcohol into half a tank of gasoline and run it back through again. Supposedly that will let me pass the test; which is cool because I'm yanking the 305 out and dropping in a 350 by the end of April anyway.
 
Well I wish you luck and the offer still stands. If its that close to passing it can be done. Try running it a little leaner /forums/images/graemlins/k5.gif
 
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If it failed for CO, then its running rich, check the air fuel ratio.

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I thought the stock carbs on these smog trucks couldn't be adjusted. How would I adjust the air fuel ratio?
 
[ QUOTE ]
I thought the stock carbs on these smog trucks couldn't be adjusted. How would I adjust the air fuel ratio?


[/ QUOTE ]
If the carb is NOT a feedback (electric) carb then you could could pop off the blocking plugs on top of mixture screws(easier if carb removed) and use the tool napa sells to turn mixture screws. /forums/images/graemlins/thumb.gif
 
Cool... thanks. I think I will just push forward and swap the new 350 into the Blazer and fiddle with the shiny new Edelbrock carb instead. /forums/images/graemlins/grin.gif
 
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