Muffler delete equals Rich condition

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.

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SS_Firehawk

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.

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cavemancan

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

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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.

stewarts2008

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?

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2010 370z Touring | K&N Typhoon
2013 Mustang 5.0 | 650 rwhp (sold)
2011 Mustang V6 | 270 rwhp (sold)

cavemancan

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.

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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.