Help! 370z weird exhaust sounds

fuentes2s · 08-07-2022, 03:11 AM

So recently my exhaust, Tomei catback/Megan Y pipe/Stock cats, has been sounding droney and muffled like it lost power. Car sounds almost farty during warm idle.

It threw code p2a00 and p2a03, wondering what it can be hoping its just an exhaust leak.

BettyZ · 08-07-2022, 08:48 AM

Sounds like a leak for sure

fuentes2s · 08-07-2022, 11:19 AM

my temps have been extremely high. Usually 180-200 average. Lately theyve been 220-250 when I run it hard. Could it be a blocked catalytic ?

BettyZ · 08-07-2022, 05:13 PM

Quote:

Originally Posted by fuentes2s

my temps have been extremely high. Usually 180-200 average. Lately theyve been 220-250 when I run it hard. Could it be a blocked catalytic ?

How many miles on the cats?

fuentes2s · 08-07-2022, 08:36 PM

93k miles on the cats

BettyZ · 08-08-2022, 08:21 AM

Hm. You're throwing codes for both banks so unless both cats sh*t the litterbox at the same time I don't think it's a blocked kitty. Could be a fuel issue.

Spooler · 08-08-2022, 08:57 AM

Quote:

Originally Posted by fuentes2s

my temps have been extremely high. Usually 180-200 average. Lately theyve been 220-250 when I run it hard. Could it be a blocked catalytic ?

Oil temps? If so, that is about normal for a 2012 with stock heat exchanger. Even with an 34 row oil cooler they can get that hot if on track or in the mountains on a curvy road.

Corsairprime · 08-08-2022, 10:45 AM

Could also be that the AFR sensors in the exhaust track (the first ones) finally gave up. Mine quit around 110k Miles. If you run an OBD2 scanner program, you might see some anomalous readings on the AFR circuits. This is what I noticed and prompted me to replace them both.

Just a thought, but check your exhaust for leaks too.

THE BULL · 08-08-2022, 03:03 PM

Quote:

Originally Posted by Corsairprime

Could also be that the AFR sensors in the exhaust track (the first ones) finally gave up. Mine quit around 110k Miles. If you run an OBD2 scanner program, you might see some anomalous readings on the AFR circuits. This is what I noticed and prompted me to replace them both.

Just a thought, but check your exhaust for leaks too.

Correct.

You should be able to monitor your A/Fs to find out if they are operating at all.
Going from a normal sound to a weird sound can be a leak, it can also mean that the cats are done and they messed up the A/Fs as they went.

With the cats clogged the A/Fs will take a beating many times overheating, you can monitor catalytic temp through the A/F sensors.

Any issues with these sensors will usually send the engine into default fuel parameters which mean pig rich airfuels.

I suggest you monitor the A/F readings then take off your exhaust and check those cats.

Dreadnaught · 08-09-2022, 12:04 AM

Once you get the car up in the air you could also check the cats by hitting them with a dead blow hammer and listen for the inside of the cat rattling around as you hit it.

fuentes2s · 08-11-2022, 06:25 PM

Quote:

Originally Posted by THE BULL

Correct.

You should be able to monitor your A/Fs to find out if they are operating at all.
Going from a normal sound to a weird sound can be a leak, it can also mean that the cats are done and they messed up the A/Fs as they went.

With the cats clogged the A/Fs will take a beating many times overheating, you can monitor catalytic temp through the A/F sensors.

Any issues with these sensors will usually send the engine into default fuel parameters which mean pig rich airfuels.

I suggest you monitor the A/F readings then take off your exhaust and check those cats.

Here are the A/F Sensors readings. Volts are low im assuming? Going to replace both upstream sensors

08-07-2022, 08:48 AM	#2 (permalink)
BettyZ A True Z Fanatic Join Date: Aug 2018 Location: Chicagoland Age: 38 Posts: 5,261 Drives: A Garage Queen Rep Power: 2684371	Sounds like a leak for sure __________________ '14 MB Nismo \| Boost Lab 6870 1.32 AR 553 HP / 471 ft.-lbs. Betty Mods

08-08-2022, 08:21 AM	#6 (permalink)
BettyZ A True Z Fanatic Join Date: Aug 2018 Location: Chicagoland Age: 38 Posts: 5,261 Drives: A Garage Queen Rep Power: 2684371	Hm. You're throwing codes for both banks so unless both cats sh*t the litterbox at the same time I don't think it's a blocked kitty. Could be a fuel issue. JARblue likes this. __________________ '14 MB Nismo \| Boost Lab 6870 1.32 AR 553 HP / 471 ft.-lbs. Betty Mods

08-08-2022, 10:45 AM	#8 (permalink)
Corsairprime Base Member Join Date: May 2014 Location: Frisco, TX Posts: 215 Drives: 14 370Z Nismo GM 6MT Rep Power: 3545	Could also be that the AFR sensors in the exhaust track (the first ones) finally gave up. Mine quit around 110k Miles. If you run an OBD2 scanner program, you might see some anomalous readings on the AFR circuits. This is what I noticed and prompted me to replace them both. Just a thought, but check your exhaust for leaks too. BettyZ likes this. __________________ Corsairprime 2014 Nismo #462, GunMetal Grey, GT-R Start Button, AAM S-Line/R-Line intake and S-Line exhaust, Berk HFCs, Osiris Tuned at JoTech

08-09-2022, 12:04 AM	#10 (permalink)
Dreadnaught Track Member Join Date: Dec 2009 Location: Farmington, Utah Posts: 582 Drives: 14 SR 370z 6MT Rep Power: 10140	Once you get the car up in the air you could also check the cats by hitting them with a dead blow hammer and listen for the inside of the cat rattling around as you hit it. Optimiser likes this. __________________ Ford Diesel and Heavy Line Technician at your service.

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08-07-2022, 11:19 AM	#3 (permalink)
fuentes2s Base Member Join Date: Nov 2021 Location: Los Angeles Posts: 12 Drives: 2012 Nismo 370z PW Rep Power: 4	my temps have been extremely high. Usually 180-200 average. Lately theyve been 220-250 when I run it hard. Could it be a blocked catalytic ?

08-07-2022, 08:36 PM	#5 (permalink)
fuentes2s Base Member Join Date: Nov 2021 Location: Los Angeles Posts: 12 Drives: 2012 Nismo 370z PW Rep Power: 4	93k miles on the cats