Failed Emissions Miserably!
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From: Skippack, PA
Originally Posted by flame
Start off by giving us they actual #'s and the limits of each HC, CO, Nox
I used my stock tune with Pacesetters and dual small bullet cats and just barely passed. Its possible that your single cat is not efficient in its location and remember that the universal cat is less eficient than stock in emission reduction to begin with. The EGR is going to be your next obstacle because theres not enough back pressure with headers for the valve to function. Ion can give you a header EGR tune thats supposed to work. Generally the tuning will lean out the stock fuel curve as GM runs them rich. Lastly when you live in a location that has emission testing with the sniffer its in your best interest to keep your stock pcm for that purpose.
I used my stock tune with Pacesetters and dual small bullet cats and just barely passed. Its possible that your single cat is not efficient in its location and remember that the universal cat is less eficient than stock in emission reduction to begin with. The EGR is going to be your next obstacle because theres not enough back pressure with headers for the valve to function. Ion can give you a header EGR tune thats supposed to work. Generally the tuning will lean out the stock fuel curve as GM runs them rich. Lastly when you live in a location that has emission testing with the sniffer its in your best interest to keep your stock pcm for that purpose.
Ok, its an idling test and here are the categories:
1.) CO % x liters Limit: 1.10 Test Value: 3.64
2.) HC ppm x liters Limit 275 Test Value 729
3.) NO ppm x liters Limit 3600 Test Value 5876
My car use to idle around 700rpm until my tune which boosted idle to 900rpm.
Also the tune reduced my gas mileage by 5mpg so I know that my MadZ28 tune is a problem even if it isnt affected my emissions.
When I had it tuned, I did have it tuned for premium gas power tuning so my timing was boosted as well as shift points adjusted etc. if thats a possible reason why???
Tomorrow I'm installing a stock pcm and thermostat so I will have it tested and see what happens. I can't see just my Cat causing my readings to be that far off so there's gotta be more than one issue here.
Last edited by StealthFormula; Jun 9, 2006 at 03:56 PM.
Thats weird that they test Nox if its just an idle test. The EGR system will not be used at idle so you don't need to worry about that. With no cat your readings wouldn't even be that high. Hopefully it was just something messed up in the tune.
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From: Skippack, PA
Originally Posted by slagger
do you have cats tuner, and if you can send me your pcm file?
i'll look at it and see what might be the probleme.
i'll look at it and see what might be the probleme.
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From: Skippack, PA
I talked to a guy at my local Pontiac dealer and he said with a stock computer and thermostat along with 30 minutes of hard driving before the test, my car will pass.
Well I do find it odd that your mpg was reduced by 5 with the tune. I guess if you will find out if that's the problem when you test with the stock computer.
Some cars just have a hard time passing with longtubes.
Some cars just have a hard time passing with longtubes.
Did you replace your O2 sensors when you put in the headers? If so, they may have been contaminated and aren't giving proper readings resulting in the rich condition. I left my old O2's in for the first couple of weeks as the headers burned off the coating residue, then put new O2's in.
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From: Skippack, PA
Originally Posted by JL8Jeff
Did you replace your O2 sensors when you put in the headers? If so, they may have been contaminated and aren't giving proper readings resulting in the rich condition. I left my old O2's in for the first couple of weeks as the headers burned off the coating residue, then put new O2's in.
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From: Skippack, PA
Originally Posted by flame
So how did you make out with this??
