Can P0420 error code be caused by air/fuel ratio gauge?
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Can P0420 error code be caused by air/fuel ratio gauge?
I have a 2005 EVO and recently I installed an Autometer air/fuel ratio gauge which is using stock o2 sensor. Next day I noticed a "SERVICE ENGINE SOON" light. I checked at Autozone and it was a P0420 error code (Catalyst efficiency below threshold- bank 1). I rewired everything again and it was fine for a few weeks until yesterday. The light came on again with the same code. Can it be caused by a/f ratio gauge itself???
Last edited by dvd_mi; Oct 26, 2009 at 06:29 PM.
Thread Starter
Evolving Member
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From: Central Connecticut
No fuses blow and car runs perfectly. I erased the code and it is running fine for 2 days now. I have a 3" buschur racing exhaust with 3" buschur high flow cat converter. It was installed about year ago. and everything was fine. Recently i installed a 3" downpipe and still no problems, until few days ago when i installed that gauge.
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so your using your second o2 sensor for the gauge? does that mean your sensor isn't reading for the cars ecu anymore? If so that will throw a code. Your car only has that second o2 sensor for your emissions i believe. If you take it so that its not reading for the ecu then you'll throw a code cause your car will think the cat isn't working right.
If its just reading for both then then your high flow cat isn't burning enough for exceptable level in your exhaust or your high flow cat is fowled. There is two threads around here to fix that if that is the case. What you do is drill out a spark plug anti fowler a certain way and it makes the sensor not sense as much exhaust which will keep your cel off. I have a test pipe and i'm using this method to keep mine off.
If its just reading for both then then your high flow cat isn't burning enough for exceptable level in your exhaust or your high flow cat is fowled. There is two threads around here to fix that if that is the case. What you do is drill out a spark plug anti fowler a certain way and it makes the sensor not sense as much exhaust which will keep your cel off. I have a test pipe and i'm using this method to keep mine off.
I can't believe no one has told you this yet!!!
Remove the Autometer Air/Fuel gauge and sell it to some ricer. It does absolutely nothing but look like a flashy, blinky light.
The Autometer and stock O2 sensor are a narrowband setup, so that means they work from 0-1 volts and are useless from a tuning standpoint. The real Air/Fuel gauges (like AEM, Innovate, etc) have their own O2 sensor and are a wideband setup, so that means they work from 0-5 volts and are actually useful from a tuning standpoint.
AGAIN, SELL THE AUTOMETER GAUGE....YOU WASTED YOUR MONEY ON IT.
Remove the Autometer Air/Fuel gauge and sell it to some ricer. It does absolutely nothing but look like a flashy, blinky light.
The Autometer and stock O2 sensor are a narrowband setup, so that means they work from 0-1 volts and are useless from a tuning standpoint. The real Air/Fuel gauges (like AEM, Innovate, etc) have their own O2 sensor and are a wideband setup, so that means they work from 0-5 volts and are actually useful from a tuning standpoint.
AGAIN, SELL THE AUTOMETER GAUGE....YOU WASTED YOUR MONEY ON IT.
Last edited by SloRice; Oct 29, 2009 at 06:48 AM.
