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Old 09-21-2012, 02:34 PM   #1
rtodnem
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2005 WRX modified
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Default O2 sensor delete?

Hi guys,
I'm working on a set of custom headers for a WRX 2.0L, up & down pipe, and was wondering if I could avoid using the two stock O2 sensors and just use one wide band O2 after the turbo. Does the stock ECU reset take care of any CELs or can a Cobb AP be used to cancel the CELs??

Thanks for the help,
Richard
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Old 09-21-2012, 03:04 PM   #2
leecea
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The rear O2 sensor is just to measure cat efficiency and I'm pretty sure it can be faked with a resistor or the CEL can be turned off by the tune.

The front sensor is important to how the car runs when in closed loop mode. Whether you can tune the car to rely solely on a wideband after the turbo is beyond me. I'm guessing it's simpler just to weld a bung into the header.
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Old 09-21-2012, 09:59 PM   #3
HinshawWRX
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No, just no.

The front o2 sensor is the primary sensor to determine the engine parameters. You cannot replace/delete this, it is 100% NECESSARY. The seconday (bank 2), after turbo o2 sensor can be removed. You will need to disable the CEL for this with a tune.

There is no need to "avoid using" 2 sensors, you rarely have to change them, and are more for safety then anything.
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Old 09-21-2012, 10:41 PM   #4
the suicidal eggroll
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Quote:
Originally Posted by HinshawWRX View Post
The seconday (bank 2), after turbo o2 sensor can be removed.
Note that this is only true for the 16-bit ECU (02-05 WRX). Removing the rear o2 will cause closed loop fueling problems on the 32-bit ECU.
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Old 09-21-2012, 10:48 PM   #5
rtodnem
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Thanks guys. So if I use the OEM O2 sensors, where is the best location for the wide band?
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Old 09-21-2012, 10:58 PM   #6
HinshawWRX
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Depends on which wideband you have, follow the directions that come with it.
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Old 09-21-2012, 11:02 PM   #7
novacivic
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Quote:
Originally Posted by the suicidal eggroll View Post

Note that this is only true for the 16-bit ECU (02-05 WRX). Removing the rear o2 will cause closed loop fueling problems on the 32-bit ECU.
Not true. We have done it many times at the shop I work at. Most recent was an 08 sti with AMs rotated kit and also running speed density. Deleting the rear o2 caused zero negative affects once the codes were turned off.
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Old 09-21-2012, 11:13 PM   #8
the suicidal eggroll
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Quote:
Originally Posted by novacivic View Post
Not true. We have done it many times at the shop I work at. Most recent was an 08 sti with AMs rotated kit and also running speed density. Deleting the rear o2 caused zero negative affects once the codes were turned off.
Um, yes true

Removing the rear O2 changes the closed loop fueling target on the 32-bit ECU. I've seen it in person and it's also discussed here:
http://www.romraider.com/forum/topic3588.html

Backed up by the FSM, Cobb, and the developer of RomRaider.

Last edited by the suicidal eggroll; 09-21-2012 at 11:24 PM.
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Old 09-21-2012, 11:43 PM   #9
novacivic
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Quote:
Originally Posted by the suicidal eggroll View Post

Um, yes true

Removing the rear O2 changes the closed loop fueling target on the 32-bit ECU. I've seen it in person and it's also discussed here:
http://www.romraider.com/forum/topic3588.html

Backed up by the FSM, Cobb, and the developer of RomRaider.
Ok so explain to me why we have had zero issues when doing it
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Old 09-21-2012, 11:45 PM   #10
the suicidal eggroll
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Maybe you're not looking at the right parameters? It's been proven time and time again.
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