Custom EFI Live tune;failed emissions big time
#21
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So are you pointing to failing or poor quality O2 sensors? Is one brand versus another noted for shorter switching speeds? I think I'm following the concept, it is back to Jimmyblue's point that the PCM is 'chasing' the slow switching and chasing back and forth between rich and lean. What would be the action plan to fix?
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OP, I run the Rear Corvette O2 Sensors up front. I also have headers and high-flow cats. When I originally lived in the emissions testing zone I passed with flying colors (220/220 114 cam) utilizing the above O2 sensors.
You will various reviews on differing O2 setups. The bottom line is they tend to get dirty and fail easily. The farther displacement away from the original manifold location, also tends to skew the temperature and switching ability of the O2 sensors.
You just have to replace them more frequently. Not that much money. It may or may nor be the cause of your fail. But, it is an easy fix. If you are running closed-loop you need them to properly maintain stoich anyway.
I would try the easy fix first. Good luck..
You will various reviews on differing O2 setups. The bottom line is they tend to get dirty and fail easily. The farther displacement away from the original manifold location, also tends to skew the temperature and switching ability of the O2 sensors.
You just have to replace them more frequently. Not that much money. It may or may nor be the cause of your fail. But, it is an easy fix. If you are running closed-loop you need them to properly maintain stoich anyway.
I would try the easy fix first. Good luck..
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I think it was the longer harness length..I forget the exact dimensions, but they were easy to hook up and did not require extensions.
Whether their ability to 'heat-up' is really any better than the stock O2's have been widely debated. Primarily convenience..so far they have lasted several years. My only issue is one that is common with long-tube headers..they are just simply farther away from the stock manifold, so they tend to run 'colder' than stock location.
But, the bottom line is that for me they worked.
Hope that helps..
Whether their ability to 'heat-up' is really any better than the stock O2's have been widely debated. Primarily convenience..so far they have lasted several years. My only issue is one that is common with long-tube headers..they are just simply farther away from the stock manifold, so they tend to run 'colder' than stock location.
But, the bottom line is that for me they worked.
Hope that helps..
#28
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My LT's are ceramic coated (IDK if this makes a difference), when I run them the O2's seem to switch ok (I'll dig thru my logs... I run mostly OLSD tho, so it may be hard to find some CL logs with the LT's).
#29
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My QTPs are ceramic coated as well. Just replaced O2's with Bosch 13111s, new set of NGK TR6's gapped to .055, drove it for about 15 minutes and took it back in. Now I've easily passed the HC and CO2 checks, the limit on NOx is 1.500, I came in a 1.579. Failed me. Huge difference in results, but a whisker short of success.
#32
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Magnaflow bullets, metal substrate. About 4K miles on them. 12 months old. Most of those miles on the 2009 Power Tour and the trip I took to Kansas City last week. Complete pain in the a$$ at the testing facility, there is always a wait, so the car cools.
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I would call one of the facilities and talk to a manager. Explain that excessive wait time is cooling off your cats and making the test ineffective. Request assistance in scheduling and ask for expedited service.
You will be surprised how a little bit of diplomacy and flexibility on your part will help. If all else fails you can always locate one of Denver's drive-by smog vehicles (Air Care Colorado?) and do a pass-by. Thats always a little harder to successfully pass, but those are some ideas.
If all else fails, get a mail drop..Legally of course.
Good luck. I bet with your cats warm you can pass..
You will be surprised how a little bit of diplomacy and flexibility on your part will help. If all else fails you can always locate one of Denver's drive-by smog vehicles (Air Care Colorado?) and do a pass-by. Thats always a little harder to successfully pass, but those are some ideas.
If all else fails, get a mail drop..Legally of course.
Good luck. I bet with your cats warm you can pass..
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I really think they will accommodate a reasonable request to keep the car running and keep the cats warm. But, OP any 'trick' you can legitimately use I would go for it..
#38
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I gave in and bought the EFI Live tuning software to go with my scan tool. I've contacted the original tuner, he will ship me the stock tune, then I can flip between the factory tune and the performance tune. I'm failing the NOx on acceleration, that is where the AFR goes fat. It normally runs at Stoich, but >65% or 70% throttle position sensor open it drops to 11.3. I suspect the extra fuel has some cooling affect, but still, more fuel will result in more emission. Wish me luck. This way I can tune out the rear O2 sensors, adjust my cooling fan operating range....lots to learn now.
#40
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I gave in and bought the EFI Live tuning software to go with my scan tool. I've contacted the original tuner, he will ship me the stock tune, then I can flip between the factory tune and the performance tune. I'm failing the NOx on acceleration, that is where the AFR goes fat. It normally runs at Stoich, but >65% or 70% throttle position sensor open it drops to 11.3. I suspect the extra fuel has some cooling affect, but still, more fuel will result in more emission. Wish me luck. This way I can tune out the rear O2 sensors, adjust my cooling fan operating range....lots to learn now.
Joecar, yes, that would be the theory.