This may be a dumb question, but did you move the second O2 sensor behind the cat?

You need to have a cat between the 2 sensors so the computer can tell if the cat is working correctly. If you did, I would think that the high flow isn't doing enough to make the computer happy.

 

^^^ Thats not completly true. If your cat was not functioning correctly you would have the code catalist below threshold. I had that code so many times with the test pipe on. It would be a good idea to reset your ecu after doing the sensors. Did you do that?

 

From what I've gathered, the computer only cares how much is being emitted, not the difference between the two. I think they're are differences between RDs... OP and several others including me (and many GK owners) can just hang the second O2 sensor loose, and if the car is running cleanly enough through the first sensor the car doesn't throw a CEL. Maybe coincidentally or not, most of the cars that don't throw the CEL are lower mileage cars that are running higher grade gas than what the manual recommends (87), therefor burning slightly cleaner than the average 60k+ Tib.

Who knows, I'm probably wrong. tongue.gif

 

It does care about the difference between the two because that is how it figures if the cat is working. As for the fuel and milage thing, I had low miles and have run 93oct in the car since I bought it but the cel still came on. Your first sensor is used mostly for a/f and the second one MUST read something different than the first. If it is out of the required range then you get a cel. Or if the sensor is bad or connected incorrectly you will get a cel. The sensors are heated. So if the heating eliment is broken even tho the sensor is working correctly you will still get a cel. If the cel comes on due to the second o2 your car goes into limp mode. Which sucks by the way. As for the sensors I bought a bosch rear o2 sensor for 53 shipped. The front sensor and rear sensor are different. So if you put the same one in the rear as in the front expect some problems.

 

<div class='quotetop'>QUOTE (TibRacer01)</div><div class='quotemain'>This may be a dumb question, but did you move the second O2 sensor behind the cat?</div>


Yes, I do have a sensor before and after the cat.

<div class='quotetop'>QUOTE (UltraTibby)</div><div class='quotemain'>It would be a good idea to reset your ecu after doing the sensors. Did you do that?</div>

Yep, did that too.

Guess what? The CEL light came up again. Darn, I think the codes are P0131, highvoltage for O2 senor 1 and P0138, low voltage on O2 sensor2. I'll check the O2 wires underneath the car to make sure they're on right and didn't get disconnected.