Help, crazy knock sensor reading, low 02 sensors

fuentes2s · 10-09-2022, 08:07 PM

So my cars been throwing codes p2a00 p2a03, for upstream sensors, got those replaced as well as switched out cats for test pipe, its a nismo 2012 370z, with a tomei catback and Y pipe. Finally got around to scanning it, and its was throwing a crazy knock, in the thousands, and 02 sensors read low, and sometimes not at all lol, but car runs fine so, im thinking it might be a connection/wiring. Let me know what you guys think anything helps.

THE BULL · 10-10-2022, 01:01 PM

Quote:

Originally Posted by fuentes2s

So my cars been throwing codes p2a00 p2a03, for upstream sensors, got those replaced as well as switched out cats for test pipe, its a nismo 2012 370z, with a tomei catback and Y pipe. Finally got around to scanning it, and its was throwing a crazy knock, in the thousands, and 02 sensors read low, and sometimes not at all lol, but car runs fine so, im thinking it might be a connection/wiring. Let me know what you guys think anything helps.

You should have dealt with these issues first prior to test pipes.
O2s should have a spacer now with the tespipes.

fuentes2s · 10-10-2022, 01:23 PM

Quote:

Originally Posted by THE BULL

You should have dealt with these issues first prior to test pipes.
O2s should have a spacer now with the tespipes.

The 02 sensors are brand new Densos that I changed before taking off carts. I took the cats off because they were blown, I thought it was responsible for the 02 codes. So its not the actual sensors.

THE BULL · 10-11-2022, 11:46 AM

Now that the cats are off. 02s will be off.
Either space them or disable them via tune.

fuentes2s · 10-11-2022, 01:53 PM

The test pipes have extensions for the 02 sensors, its not the test pipes.. Did you see the picture? My knock sensor reads 12k lol, code occurred even when I had cats.

THE BULL · 10-11-2022, 02:51 PM

Many times this could be due to an exhaust leak if wiring checks out.

Spaced out 02s should work.

A vacuum cleaner on blow through the mufflers + some soapy water at your exhaust flanges will point out if there are any exhaust leaks.

Lastly a measure of your Fuel trims will point if this is an exhaust issue created by an intake leak.

fuentes2s · 10-11-2022, 04:12 PM

Fuel Trims b1 and b2 are in the picture. The percentage between them is way off, what should they be at? One says 118% and the other 98%.

10-11-2022, 01:53 PM	#5 (permalink)
fuentes2s Base Member Join Date: Nov 2021 Location: Los Angeles Posts: 12 Drives: 2012 Nismo 370z PW Rep Power: 4	The test pipes have extensions for the 02 sensors, its not the test pipes.. Did you see the picture? My knock sensor reads 12k lol, code occurred even when I had cats. Last edited by fuentes2s; 10-11-2022 at 02:01 PM.

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10-11-2022, 11:46 AM	#4 (permalink)
THE BULL Base Member Join Date: Apr 2021 Location: Florida Posts: 217 Drives: G37S Rep Power: 26848	Now that the cats are off. 02s will be off. Either space them or disable them via tune.

10-11-2022, 02:51 PM	#6 (permalink)
THE BULL Base Member Join Date: Apr 2021 Location: Florida Posts: 217 Drives: G37S Rep Power: 26848	Many times this could be due to an exhaust leak if wiring checks out. Spaced out 02s should work. A vacuum cleaner on blow through the mufflers + some soapy water at your exhaust flanges will point out if there are any exhaust leaks. Lastly a measure of your Fuel trims will point if this is an exhaust issue created by an intake leak.

10-11-2022, 04:12 PM	#7 (permalink)
fuentes2s Base Member Join Date: Nov 2021 Location: Los Angeles Posts: 12 Drives: 2012 Nismo 370z PW Rep Power: 4	Fuel Trims b1 and b2 are in the picture. The percentage between them is way off, what should they be at? One says 118% and the other 98%.