NoX readings of the chart

[blazer88]

I have my blazer in the shop at the moment to be smogged, in lovely sunny Fresno, CA. At the 15mph test the nox reading was monumentally of the charts around 2200pm, passable is 750ish. It's an 84 with a 350, the computer controlled quadrajet. I have looked online at what might cause this, and have basically found a lot of people advising that running lean will cause this, or an egr not working properly. Just wonder if anybody else has had this same problem, and might have a solution or an idea to look into. I am leaving it to the shop to find the problem, I hope its an easy-ish fix and not too expensive, but that reading seems to be way off. Hopefully I stay on the road with it.

 

[scottsdale86]

Keep us updated. I have an 86 with a federal emissions carb on it so no electric accelerator pump or TPS. Wondering whats going to happen when i smog it in Feb of next year.

 

[ryoken]

I would definitely look to the EGR, notorious for high NOX #'s...

 

[blazer88]

Fixed!!!

Luckily I have a good shop, unfortunately they are way too busy and short handed, but done on a timely manner. A diaphragm in the EVAP canister went bad, which started a series of events. EVAP was pulling straight fuel out of the carb, causing me to run super rich, and not money in the pockets rich, two sparks plugs were fouled, O2 sensor was fouled, and my CAT was obliterated. Plus a few exhaust leaks in some old y-pipes. Everything replaced, and I am back on the road. I don't have a paper on the smog at the moment so I don't know the numbers. Gotta go by and drop off some tires monday, I will see if I can get a copy to post up some numbers. Best part, all that work cost me $171.65, had some tires and rims laying around that finally paid off. Next step is to pay the dmv and then register it out of county!!!

 

[blazer88]

You have an egr on the 86???

 

[scottsdale86]

my question is did gm start with o2 sensors in 84?

 

[blazer88]

not sure what year that 02 sensors started being used in, probably the same year they started using computer controlled carbs. My book i have does not go that in depth.

 

[blazer88]

Passed Smog

15mph@1550 RPM
%co2-13.72
%o2-1.82
HC(PPM)60
CO(%).10
NO(PPM)265

25mph@1567RPM
%co2-14.72
%02-.88
HC(PPM)25
CO(%).02
NO(PPM)214

Now to pay the DMV

 

[79rustyk10]

I am SOOOOOOOOOOOOOOO glad I dont have to deal with that crap here. Mn is going liberal and a future Ca it seems, so Ill probably have to deal with it at some point.