Will the mechanical O2 fix screw up the A/F ratio?
Thread Starter
Evolving Member
Joined: Dec 2007
Posts: 229
Likes: 14
From: Winter Haven Fl
Will the mechanical O2 fix screw up the A/F ratio?
NOt much more to say then the title. I am switching from a magnaflow HFC to a mil.spec 100 cell. Sean @ Ivey said I do not need a retune for the cat, but if I do a mechanical fix for the CEL I am worried that my car may run lean. Does the computer use the cat mounted O2 sensor to adjust the fuel mixture, or does it use a different sensor upstream?
Evolved Member
Joined: Feb 2006
Posts: 1,345
Likes: 1
From: MA
NOt much more to say then the title. I am switching from a magnaflow HFC to a mil.spec 100 cell. Sean @ Ivey said I do not need a retune for the cat, but if I do a mechanical fix for the CEL I am worried that my car may run lean. Does the computer use the cat mounted O2 sensor to adjust the fuel mixture, or does it use a different sensor upstream?
haha. the secondary o2 sensor is only used to check cat efficiency. it will not effect A/F. some of us don't even run a secondary o2 sensor.
edit: The primary o2 sensor is located on the turbo outlet. thats why most people call this piece an "o2 housing"
Last edited by EvoBroMA; Aug 21, 2008 at 07:57 AM.
Thread Starter
Evolving Member
Joined: Dec 2007
Posts: 229
Likes: 14
From: Winter Haven Fl
Thanks that is what I thought, but I wanted to be sure. I knew people ran with a resistor in place of the O2 sensor, but I thought it was possible they flashed the ECU to get the A/F right, and it is better safe then buying a new motor.
Evolved Member
Joined: Feb 2006
Posts: 1,345
Likes: 1
From: MA
no prob! its better to ask and learn, then be sorry you screwed something up.
