Failed smog test, why?

[b8180]

I have a 95 GST that I bought in July 2008 so this is the first time I have smogged it. It turns out that it's a gross polluter. Can anyone tell me whats wrong with it by looking at the results? thanks.

http://webpages.charter.net/bjp8180/Smog results.htm

 

[Nati0nalxCrisis]

What kind of exhaust are you running, so on so forth.

A little more information would be helpful, for me atleast.

Someone else might be able to help you with less, but I'll try my best if you can give me a bit more.

 

[b8180]

My exhaust is all stock, I removed my intake for the test so as of right now it's all stock.

 

[Nati0nalxCrisis]

Well really it could be a number of things then.

Spark plugs
Catalytic Converter
O2 Sensor

I'd say first check your sparkplugs, if they're not sparking good this could deff cause you to fail. That should take you 15 minutes tops.

Keep us updated. I'll keep looking around in the mean time.

 

[DSMopar]

Where's your NOX? Your HC is pretty high, as with your CO (obviously). When's the last time you did plugs/wires? Do you have a CAT in your exhaust?

 

[b8180]

NOX
271
106

I have a CAT and I last did my plugs (BPR6ES) and wires last August.

 

[jeffo]

How old is the CAT? How old is the O2 sensor? Have you checked for boost leaks lately?

 

[xhackerekx]

check u egr .

 

[92rsAWD4me]

I went through this with the Laser. Check your EGR valve and also the ports leading to it. Also have somebody test your O2 sensor. What fixed mine was O2 sensor and cleaning out all the crap in the ports around the EGR valve. This fixed my idle, completely cleaned up my emissions, and made the car run a million times better.

 

[b8180]

Thanks for the info guys, I changed my plugs and oil today and will check the O2 sensor and EGR this week.

 

[bomper04]

Guys, do yourselves a favor and go and Google what these gases are and what causes them. An EGR WILL NOT cause HIGH CO and HIGH HC's. If you're familiar with the intended purpose of the EGR valve you would know that it's sole purpose is to aid in the reduction of combustion chamber temps to help reduce the creations of NOx. READ READ READ, please. From the info you provided us with, you are running rich. HC's are caused by incomplete combustion and CO is caused by partial combustion. Your oxygen is at zero so we know we're burning all of what we can. Your CO2 is nice at 14.1% @ 15mph but as we can see, drops to 11.5%. CO2 is an indicator of combustion efficiency. So you're not misfiring, otherwise you would have super high HC's. My advice to you, start looking around. I would inspect the vacuum line to the fuel pressure regulator. Higher than normal CO and HC's can be caused by this. If everything checks out okay with your vacuum source, check the valve itself, apply vacuum to it with a vacuum pump and see if it is able to hold pressure. From there you can try monitoring 02 sensor traces and look at the upstream and downstream signals. This will tell you whether or not it is switching fast enough and will also be able to tell you whether or not your catalytic converter is working. Hope this helps.

 

[b8180]

Update: it was the O2 sensor that needed to be replaced. Thanks for all your help.

 

[bomper04]

Good stuff, bro.