Muffler delete equals Rich condition

robones · 08-13-2012, 01:05 PM

They may give you a hard time even with the FI. If the dealer is to try to find the reason why you are running rich (which has to do with the info from the intake and various exhaust sensors) they may say, well you have an aftermarket exhaust which may be causing your condition. As you may already know, running rich is bad for your car. Fouls the plugs, bad for your CAT and of course really poor fuel economy.

cavemancan · 08-13-2012, 01:14 PM

Quote:

Originally Posted by MyKindaGuise

Sounds like bad O2 sensor dude. Just went through this with my headers. My one plug was slightly cracked so the wires werent making a complete connection on the one sensor. I was getting 10-12 city and 15-17 highway....pulled the plug and now I'm at 18 city and 28 highway. Plug for you is easy to replace anyone 2011 and up will be a bitch. They use different plugs and the dealerships can't even order them...having one specially made :/

The irony is if it were that simple I would be happy but my brother checked the sensors with this tool and they are ok. I have an extended warrantee untill 100k miles so I am all set in that regard. It's the not knowing that is killing me.

Sales@AAMComp · 08-17-2012, 09:46 AM

OP are you sure you didn't get the case of "my car is louder so my foot got heavier"? Theoretically a muffler delete really shouldn't have any plan in a/f ratios but I'd like to see what the outcome of this really is. I highly doubt it relates to the muffler delete

Maybe put the stocker back on and see if the mpg goes back?

kenny's 370z · 08-17-2012, 10:01 AM

i have done a muffler delete and tb bypass's.that was my first mods and when i bought the car,the computer said i was getting 18.5 miles to the gallon.after delete and bypasses,i havnt seen under 20.

Nak4mura · 05-22-2013, 07:36 PM

I just did the muffler delete last week and had the tips custom welded back on and sometimes usually when I am getting on it I can smell gas. I mentioned it to my buddy and he said it means its running rich. I asked the shop before hand if it could have any negative impact and they said no it will just change the sound. So if it is causing a rich condition (which would suck...) then I will go have the muffler put back on.

JARblue · 05-22-2013, 07:53 PM

I just got a tune this past weekend, and after several discussions with various people of varying knowledge, I believe that the car runs rich regardless. Has anyone ever seen a stock 370Z that isn't running rich? With an 11:1 compression, it's likely Nissan just being cautious. They have to run it even richer to account for uncaring drivers who use regular gas.

I amfully stock except for intakes (which, if anything, should make it leaner) and my tuner said I was running extremely rich.

SS_Firehawk · 05-22-2013, 07:59 PM

Quote:

Originally Posted by SS_Firehawk

A bad O2 sensor doesn't throws a code. It took a long time before I figured out I had a bad sensor. Cipher helped me track it down. And yes, it ran pig rich.

Let me revise this and say it doesn't bluntly say your O2 sensor is messed up when you look it up. It was a ver common P0300 code and maybe something else that did nothing to help track it down. Data logging was the only way I saw it.

cavemancan · 05-23-2013, 05:22 PM

After installing my FI exhaust my gas mileage went back to normal.

HumbleZ34 · 05-26-2013, 07:02 AM

It's your o2 sensor. Happened to my Z also

stewarts2008 · 06-20-2013, 06:35 PM

Quote:

Originally Posted by cavemancan

After installing my FI exhaust my gas mileage went back to normal.

so you fixed it? What was it?

If your muffler delete was rattling, then yes, the knock sensors could have picked up vibrations.

Im not sure how loud it was, but if you car was crazy loud, then the knock sensors can pick up on that in general.

any updates?

cavemancan · 07-05-2013, 06:09 PM

Still running with stock gas mileage when I installed the FI exhaust. I honestly cannot give you a definitive answer as to why it ran rich with the muffler delete but perhaps the knock sensor theory has some merit? I don't think so but perhaps.

Shortly after the FI install I also installed the Takeda intake. The only change was a HP increase. Mileage while cruising on the highway is more or less the same. I have 15k + miles with both mods without any issues. So I consider the issue resolved.

08-17-2012, 09:46 AM	#18 (permalink)
Sales@AAMComp A True Z Fanatic Join Date: Jul 2012 Location: Annapolis Junction, MD Posts: 4,079 Drives: GT-R Rep Power: 20	OP are you sure you didn't get the case of "my car is louder so my foot got heavier"? Theoretically a muffler delete really shouldn't have any plan in a/f ratios but I'd like to see what the outcome of this really is. I highly doubt it relates to the muffler delete Maybe put the stocker back on and see if the mpg goes back? __________________ Tyler Day, Technical Sales TylerD@aamcompetition.com 301-497-9214 Direct AAM Competition \| YouTube channel \| LIKE us on Facebook!

05-22-2013, 07:53 PM	#21 (permalink)
JARblue A True Z Fanatic Join Date: Mar 2011 Location: Austin, TX Age: 43 Posts: 36,449 Drives: 11 Z34, 98 E36 M3 Rep Power: 2684440	I just got a tune this past weekend, and after several discussions with various people of varying knowledge, I believe that the car runs rich regardless. Has anyone ever seen a stock 370Z that isn't running rich? With an 11:1 compression, it's likely Nissan just being cautious. They have to run it even richer to account for uncaring drivers who use regular gas. I amfully stock except for intakes (which, if anything, should make it leaner) and my tuner said I was running extremely rich. __________________ 2011 370Z 6MT Sport Gun Metallic \| ARC \| CJM \| Ecutek \| FI \| Fujimura \| R2C \| SPL \| Stillen \| TWM \| Z1 \| ZSpeed \|

05-23-2013, 05:22 PM	#23 (permalink)
cavemancan Enthusiast Member Join Date: Mar 2012 Location: Miami Posts: 302 Drives: 09 370Z TourSport MT Rep Power: 249	After installing my FI exhaust my gas mileage went back to normal. __________________ Mazda Rx8 MT Titanium - SOLD! 2009 370Z T-Sport MT Black - Takeda Intake, Swift springs, Rear Camber kit, SS B Lines, FI Exhaust, Z Speed CMAK Flywheel/Clutch Kit, Stillen Brake Cooling.

07-05-2013, 06:09 PM	#26 (permalink)
cavemancan Enthusiast Member Join Date: Mar 2012 Location: Miami Posts: 302 Drives: 09 370Z TourSport MT Rep Power: 249	Still running with stock gas mileage when I installed the FI exhaust. I honestly cannot give you a definitive answer as to why it ran rich with the muffler delete but perhaps the knock sensor theory has some merit? I don't think so but perhaps. Shortly after the FI install I also installed the Takeda intake. The only change was a HP increase. Mileage while cruising on the highway is more or less the same. I have 15k + miles with both mods without any issues. So I consider the issue resolved. __________________ Mazda Rx8 MT Titanium - SOLD! 2009 370Z T-Sport MT Black - Takeda Intake, Swift springs, Rear Camber kit, SS B Lines, FI Exhaust, Z Speed CMAK Flywheel/Clutch Kit, Stillen Brake Cooling.

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08-13-2012, 01:05 PM	#16 (permalink)
robones Enthusiast Member Join Date: Mar 2011 Location: Miami Posts: 357 Drives: 2011 - Nissan 370 M6 Rep Power: 14	They may give you a hard time even with the FI. If the dealer is to try to find the reason why you are running rich (which has to do with the info from the intake and various exhaust sensors) they may say, well you have an aftermarket exhaust which may be causing your condition. As you may already know, running rich is bad for your car. Fouls the plugs, bad for your CAT and of course really poor fuel economy.

08-17-2012, 10:01 AM	#19 (permalink)
kenny's 370z Base Member Join Date: Jun 2012 Location: TN Age: 58 Posts: 243 Drives: 2012 frontier sv v6 Rep Power: 12	i have done a muffler delete and tb bypass's.that was my first mods and when i bought the car,the computer said i was getting 18.5 miles to the gallon.after delete and bypasses,i havnt seen under 20.

05-22-2013, 07:36 PM	#20 (permalink)
Nak4mura Base Member Join Date: Jul 2012 Location: Puyallup WA Posts: 48 Drives: 2009 Nismo370z Rep Power: 12	I just did the muffler delete last week and had the tips custom welded back on and sometimes usually when I am getting on it I can smell gas. I mentioned it to my buddy and he said it means its running rich. I asked the shop before hand if it could have any negative impact and they said no it will just change the sound. So if it is causing a rich condition (which would suck...) then I will go have the muffler put back on.

05-26-2013, 07:02 AM	#24 (permalink)
HumbleZ34 Base Member Join Date: May 2013 Location: Under a bridge Posts: 24 Drives: Slowly :) Rep Power: 12	It's your o2 sensor. Happened to my Z also