Throwing code P0420A
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Teching In
Joined: Jun 2011
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Throwing code P0420A I have a 1998 camaro, LS1 engine with 50k original miles, throwing a variety of codes daily, all since adding Pacesetter long tube headers, custom exhaust, Magnaflow hi-flo cats, and K&N cold air intake. Had to extend the wiring harness in the process. Replaced both front O2 sensors (with AC Delco O2 sensors) after exhaust and air intake were installed because she was throwing code P0153, mechanic scanned all four O2 sensors, found bank 1 sensor 1 was switching slow (even though the code indicated it was the bank 2 sensor), replaced bank 1 sensor 1, then threw codes P0153 and P0133. Replaced bank 1 sensor 1 again, also replaced bank 2 sensor 1. Then she threw code P0420a. Moved bank 1 rear O2 sensor back in exhaust pipe by 3" (used infared thermometer to determine correct location for temperature needed), still throwing code P0420a. Really starting to get frustrated...this has been going on for nearly 3 months, mechanic is very reputalbe, has done many custom exhaust packages, never had issues like this. I refuse to put O2 simulators on this car, which has been mentioned as an option. Not sure if replacing both rear O2 sensors would resolve, not sure if maybe the cats were damaged (car was running very rich) before front O2 sensors were replaced or if the cats might be defective (although I've never heard of issues with Magnaflow). There is no way I am the only owner of a 1998 Camaro with the same modifications...someone out there must have been through this and found a resolution (without bypassing something that shouldn't need to be bypassed). Any thoughts? Assistance will be most appreciated, thank you!
Most folks, I am told, have the rear O2s turned off because most high-flow cats simply cannot pass the efficiency test required by the computer. Certain more expensive high-flow cats, such as those from Random Technology may be an exception.
(I have RT cats and they did not throw codes for several months, but I had the rear O2s turned off later anyway.)
(I have RT cats and they did not throw codes for several months, but I had the rear O2s turned off later anyway.)
