Failed Emissions in CO

ViperDEN_Nick

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Hey guys,

Did a search and most, if not all, the threads are a few years old. As the title states, failed emissions today in CO. They do both the "Sniff" and OBD.

The OBD test shows no trouble codes. The CEL test passed, and was not illuminated.

I've had the car less than a week. 1996 GTS. To my knowledge, it has a Mopar Cat-Back Exhaust, Cam and assuming a tune came with it. These are the only mods that would effect the emissions.

The readings came out:
- HC: Read, 4.59...Limit, 1.2
- CO: Read, 19.60...Limit, 15
- CO2: Read, 581...No Limt
- NOx: Read, 3.60...Limit, 2

The stock Cats are still installed. I'm not sure on the integrity of the O2 Sensors (thinking about putting on new ones). The reading I've done on failed emissions tests, these numbers indicate that the car is running on the rich side. I can see that since the car originated in GA/FL area and is now up at a higher elevation in Denver.

Aside from potentially swapping the O2 Sensors, I'm thinking about unhooking the battery to try and reset the PCM to the higher elevation and try the test again. Any other suggestions that may not break the bank?

Thanks!
 

Free2go

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A bad O2 sensor will make it run rich. Replace those and you're good to go. Welcome.
 

ViperDEN_Nick

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A bad O2 sensor will make it run rich. Replace those and you're good to go. Welcome.

Thanks for the reply Free2go!
Now, would you swap all 4? Or just the 2 that are upstream of the Cats? How much of a pain in the *** is it to get to the upstream sensors?
 

Free2go

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The two upstream should do it. I've read threads that it's pretty easy. Mine haven't needed replacing so I can't tell you from personal experience, but I'm sure someone will chime in.
 

ViperDEN_Nick

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It was a consignment purchase so we're not 100% sure it has a tune. The dealer is sure it has a cam since he's claimed to have owned 2 Gen 2 Vipers, neither of which idled like this one.

As far as brand, no idea. And we're assuming there's a tune as well, but not 100% sure.

The records I have for the car don't contain any cam/tune records.
 

Camfab

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Are you sure the OEM cats are in place and unmolested? What do the plugs look like? The OEM cats are so good that even if the car was running rich it would likely clean up the mess. Additionally if you were running that rich, the cats would be so hot that your side sill paint would be burnt.........
 

Free2go

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After I purchased my car and got it in my garage, I pulled the plugs and a few were pretty fouled.
 

ViperDEN_Nick

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Stock cats are indeed in place and the piping does not appear to have any tampering. Bought new ones anyways and will swap them out.

Also ordered new plugs and wires as the plugs look like they've never been changed.

The upstream O2 sensors were a bee-yotch to get out but I was able to get them swapped.

Next step is to swap the cats, plugs/wires, air filters, and add smooth tubes. Then drive it around for a few hours to get it hot and bring it back to the emissions place at high noon when it's hot outside, and see what happens
 

ViperDEN_Nick

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Welp, change this to "Finally PASSED Emissions in CO"

Holy smokes, it's been a crazy couple weeks. Found the car to be straight piped (mistook the Resonators as being Cats, FNG N00B!!!). Anyways, here's what I did...

-New Up/Downstream O2 Sensors from Bosch
-New Champion Spark Plugs (RC12ECC)
-New Ignition Wires from Quality Wires, thanks AB!!!
-2 Random Technology Catalytic Converters courtesy of Jon B (which upon install, turned into a Resonator delete)
-New K&N Intake Filters
-ROE Smooth Tubes
-New Mopar MAP Sensor
-New Intake Temp Sensor
-New PCV Valve
-New Crankcase Breather Element
-Tightened/Resecured all EGR connection points
-Lucas Oil Fuel System Treatment

Good to go for 2 years!

FYI, to all CO Viper owners...I found out that the Air Care Colorado near the Jeff Co DMV off Wadsworth/Chatfield will NOT run Vipers on the rollers for the sniff test. All the manager said they do is the OBD-II check and verify the seal on the fuel cap. As long as no codes are thrown, the CEL illuminates and goes out, and the fuel cap passes the seal test, they'll pass you! He had mentioned that a Viper had hopped off the rollers and caused significant damage that they don't want to be liable for anymore so the state allows them to bypass the roller/sniff. Now, it can be subjective based on a manager's approval to do the roller (as is the case at the Air Care on Colorado Blvd).
 
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speedracervr4

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Good to hear, but it sounds like you could have just put cats back on it and passed. No real need to change the IAT and MAP sensors.
 

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