I put in a high-flow cat on my 2.5'' piping, and I have not seen a check engine light yet, it has been over 4 weeks now. Anyone have any idea why it has not thrown a code yet?

 

i'm assuming this is on an OBDII car?did you install a high flow cat,or a test pipe?
Chris

 

yeah its OBD2, i put in a high-flow cat.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2lobes1engine &raquo;</TD></TR><TR><TD CLASS="quote">yeah its OBD2, i put in a high-flow cat.</TD></TR></TABLE>
Is the secondary o2 sensor installed after the cat?

 

yes, the secondary O2 sensor is behind the cat. Im beginning to think something is wrong with my O2 sensor.

 

Why.. I don't get what you're hinting at since your OP is very vague.

 

i ran a 2.5 in/out high flow with obd2 and had no cels...as long as the cat is doing its job you should have no problems. on the other hand...i SQUEAKED by emissions testing by .01

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2lobes1engine &raquo;</TD></TR><TR><TD CLASS="quote">yes, the secondary O2 sensor is behind the cat. Im beginning to think something is wrong with my O2 sensor.</TD></TR></TABLE>
Why, if there are no CELs the cat and o2 are in good condition, right?

 

is it possible to have an O2 sensor that isnt functioning, but at the same time doenst throw a code? from what i hear everyone is bound to throw a code sooner or later. most sooner than later.

 

the main purpose of the secondary o2 is to monitor the exhaust after the cat making sure it is functioning (cat) properly. if the o2 or the cat are not working the way they should you WILL get a cel

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2lobes1engine &raquo;</TD></TR><TR><TD CLASS="quote">is it possible to have an O2 sensor that isnt functioning, but at the same time doenst throw a code? from what i hear everyone is bound to throw a code sooner or later. most sooner than later.</TD></TR></TABLE>
i had an O2 sebsor in my hatch that was in such bad condition the car would barely even run,but had no code.
Chris

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2lobes1engine &raquo;</TD></TR><TR><TD CLASS="quote">is it possible to have an O2 sensor that isnt functioning, but at the same time doenst throw a code? from what i hear everyone is bound to throw a code sooner or later. most sooner than later.</TD></TR></TABLE>

Yes it's possible.

Hi-flow cat and no CEL? I don't see a problem there. What? You were expecting one? Well even if you don't have a CEL yet it doesn't mean the cat is fuctioning optimally. I have failed smog before with a Carsound but there were no CEL.

So not seeing a CEL is a good thing.