Check Engine Light!

[rosscoe21]

So on Saturday, I installed my header and test pipe with 02 spacer. Saturday and Sunday Everything was okay. This morning on my way to work the cel came on. The car didn't seem any different. I am wondering what may have caused this.:help:

[rosscoe21]

Anybody?

[gomarlins3]

Go to Autozone or other parts place and ask them to pull the code. I am guessing you need to fool the O2 sensor.

[rosscoe21]

Fool the o2 sensor? I put an 02 spacer on it. :confused:

[s2k 4 me]

You might just have to clear the cel. Check your service manual on how to do this. Mine came on when I installed the Fujita CAI. Also you can check here for more info http://forums.s2kca.com/showthread.php?t=9254

[rosscoe21]

I had advance auto read the code and it came up with P0420 Bank 1Catalyst System Efficiency Below Threshold. I reset the ecu and it hasn't came back on yet. By the way will a test pipe decrease my gas mileage?

[bimdub]

"Fool the o2 sensor? I put an 02 spacer on it."

yep...thats foolin the o2 sensor...

"I had advance auto read the code and it came up with P0420 Bank 1Catalyst System Efficiency Below Threshold. I reset the ecu and it hasn't came back on yet. By the way will a test pipe decrease my gas mileage?"

because the difference in signal between the sensors is not within the ECM specs....this can happen intermittently with the setup you have....header, test pipe.....the front o2 sensor is reading the spent fuel and the rear sensor is expecting a change from the now missing catalyst....this could be a frequent problem or an occasional oddity, or even never appear again....either way you should be prepared to expect trouble codes now and then....its the ECM doing its job! also you can expect Honda to dismiss any warranty on emmisions now, this may be no longer a concern as you may be out of warranty already but the standard is at least 75,000 miles. and you can forget most emissions testing as well, so don't move to California!

as far as mileage....it will only go down if you get on it more often! otherwise as low restriction as our "cats" are you should notice very little if not any at all difference...but if you did notice it would more likely go up a tiny bit....

I normally would go into a long rant about environmental concerns and such...even the impact on your wallet for tampering with your emissions controls....I was an Emissions technician for years before my back injury, and I personally do not approve of removing the catalyst from modern cars....but you would not listen anyway! hey its your future...your environment...the generations before me did a fine job of trashing it (they really did not know how bad it was going to get) and my generation has done everything we could to help repair it (and still be able to produce fine and powerfull sports cars)....but its your now! I leave no offspring to suffer in your wake!

[RUSSO]

:bolt: 02 sensor or did you forget to tighten your gas cap.

[gomarlins3]

P0420 isn't the gas cap.

[bimdub]

no pretty sure his gas cap is fine

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

he tried to trick the ECM into seeing a catalyst that he has removed.

sometimes this works...sometimes it don't...