3 inch turbo back exhaust with no rear O2 sensor

[JamesonTSI-AWD]

alright here is my question....I just upgraded to 3 inch turbo back exhaust an eliminated the cat so no more rear O2 sensor. I have an air to fuel gauge that now sits all the way down in the lean area......is this because there is no rear sensor to complete the fuel system? or is my car actually running this lean with out the rear o2 sensor connected? I have yet to do the rear O@ fix yet but i was just curious about this...thanks alot!

Jameson
DakotaDSM Rippin it up!

 

[CanadianTSi]

The rear o2 only tells the car that the cat is working, I have driven around for 2+ years without one and it's fine.

 

[greeneclipse]

the rear O2 sensor is pretty much useless in terms of fuel control...it's more for emission purposes to check whats coming through the cat.

 

[rampridersrider]

What if one were to put the rear O2 back in without the cat? What would that do?

 

[Liger]

Well i have been running mine with a gutted cat. I occasionally get a cel stating a cat error, that it isn't working or has dropped below some level. I have heard on other cars though that it is constantly on. All depends on the car...Brandon [VFRacing]

 

[greeneclipse]

What if one were to put the rear O2 back in without the cat? What would that do?

less chance of a CEL i guess....i've had mine hooked up into my catback and im running a test pipe. I haven't had a CEL for it in 2 years so far.

 

[JamesonTSI-AWD]

so about the a/f gauge? why isnt that working properly....all i had done was the exhaust and the a/f gauge is reading that it is all the way leaned out? is that because there is no rear 02 sensor to complete the circut or is it really running that lean???

Jameson

 

[hellotbone]

The 3" exhaust has nothing to do with your lean condition that the O2 gauge is showing. I have a 3" system and No rear O2 sensor at all and all I do is throw a code it has nothing to do with your front one.

Start with checking the front O2 sensor maybe you damaged it during the install, also check for fuel pressure your fuel pressure regulator and fuel pump something is malfunctioning to make it run lean like that.

 

[CSEclipse]

mine did the same thing when i put my apexi downpipe on and never figured out why, i checked the connections and my O2 sensor is working fine... im about to just throw away the air fuel light show and get a wideband