dead o2 sensor, replaced and now knockretard

Had an o2 sensor go bad. Only 9k miles on car. It was afr1 and I didn't know which sensor it corresponded to. So I just replaced both sensors. Car threw two codes that figured was because the sensors were unplugged, so I cleared and they didn't come back. I also took the extension harness off the drivers side and then put it on the passenger side because it's shorter and took the long extension off the passenger side. A couple weeks has passed and I noticed that my knock retard was reading positive with heavy throttle and sometimes when I get up to speed. I checked the centering of the motor and then checked the headers/exhaust from front to back and didn't see it rubbing or touching anywhere. Now this isn't my daily. It gets driven on the weekends and maybe once during the week after work. I took a couple logs and sent them to Matt@juggernaut. I'm just unsure what has happened or what I should be looking for. Would the harness' cause issues with original tune? Any suggestions are appreciated.

Mods
ngauge
jlt intake
sw 1 7/8th catless headers
corsa extreme catback
upr occ
bmr cradle lockout
bmr vertical links

You should not be using an extensions. Get them off ASAP.

2015 Silver GT said:

You should not be using an extensions. Get them off ASAP.

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I took the drivers side one off after replacing the o2 sensors but the passenger side sensor will not reach unless an extension is used. Suggestions?

xxchieferxx said:

I took the drivers side one off after replacing the o2 sensors but the passenger side sensor will not reach unless an extension is used. Suggestions?

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You're fine BBK are the ones that cause issues and yes it is needed on that side.

xxchieferxx said:

I took the drivers side one off after replacing the o2 sensors but the passenger side sensor will not reach unless an extension is used. Suggestions?

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The passenger side will reach fine once you've released the harness above the transmission.

RubyRedBoost said:

You're fine BBK are the ones that cause issues and yes it is needed on that side.

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See above.

2015 Silver GT said:

The passenger side will reach fine once you've released the harness above the transmission.


See above.

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Thank you for bestowing knowledge upon me kind sir. I don't have issues with my extensions however. Which is why I didn't pull the harness.

RubyRedBoost said:

You're fine BBK are the ones that cause issues and yes it is needed on that side.

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RubyRedBoost said:

Thank you for bestowing knowledge upon me kind sir. I don't have issues with my extensions however. Which is why I didn't pull the harness.

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You said the extensions were needed which clearly they aren't. They give false readings and have caused motor failures. Ask Terry (Beefcake Racing) about it.

Pulled apart harness at back of motor and it still won't reach.

Edit: this is a manual vehicle.

2015 Silver GT said:

You said the extensions were needed which clearly they aren't. They give false readings and have caused motor failures. Ask Terry (Beefcake Racing) about it.

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Not sure how you were able to get to reach without extensions, but both my car and a friends, there was no way in hell the factory ones were going to reach without the extensions. Both of us running Stainless works products.

jvm051 said:

Not sure how you were able to get to reach without extensions, but both my car and a friends, there was no way in hell the factory ones were going to reach without the extensions. Both of us running Stainless works products.

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I was able to get the drivers side to reach but that passenger side still comes up about 6 inches short. Maybe on the autos it can reach. After all the sw instructions do say to use extensions with the manuals :shrug:

Sub'd need to install my headers and i keep hearing different opinions about the extensions, if extensions are not recommended what are we supposed to use, my passenger side wouldn't reach, there is no way, i need a extension or something else for sure

When I installed the Texas Speed headers for another member the passenger side definitely would not reach despite releasing the harness. Was more than 10" short. I extended the wiring on the sensor for it to reach. I too hate using extensions.

http://www.mustang6g.com/forums/showpost.php?p=1436196&postcount=147

Someone mentioned to me using o2 sensors from the ford raptor but wasn't sure if they were confirmed fitment for the s550

Anyone know anything about this? I figure they are longer in wiring.

Grimace427 said:

When I installed the Texas Speed headers for another member the passenger side definitely would not reach despite releasing the harness. Was more than 10" short. I extended the wiring on the sensor for it to reach. I too hate using extensions.

http://www.mustang6g.com/forums/showpost.php?p=1436196&postcount=147

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FWIW, never solder on the o2 wiring. Always add to the vehicle harness. It changes the impedence on the o2, which is critical for a correct reading.

dev1360 said:

FWIW, never solder on the o2 wiring. Always add to the vehicle harness. It changes the impedence on the o2, which is critical for a correct reading.

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I was also told this by a highly regarded tuner. NEVER ever extend the actual o2 wires themselves. Add out factory wires.