Phx peeps - cat vs catless and emissions

[sredish]

Anyone running into issues at emissions? They look underneath for cats as far as I know, but are they really seeing them? I assume so. With the catted, as long as it's not throwing codes, should be all good then. Was considering a catless pipe but not sure I want to f with emissions and having to take off all the time.

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[AZ18yote]

Anyone running into issues at emissions? They look underneath for cats as far as I know, but are they really seeing them? I assume so. With the catted, as long as it's not throwing codes, should be all good then. Was considering a catless pipe but not sure I want to f with emissions and having to take off all the time.

As long as no CEL you should be good. Some have mentioned checking readiness monitors but I have not seen that personally here. Plus the no emissions until after 5 years from model year is a plus.

 

[Frenchy480]

Anyone running into issues at emissions? They look underneath for cats as far as I know, but are they really seeing them? I assume so. With the catted, as long as it's not throwing codes, should be all good then. Was considering a catless pipe but not sure I want to f with emissions and having to take off all the time.

I know this is bit of an older post but hope this helps for anyone in AZ. I JUST got my emmisions done yesterday on my 2016 mustang gt (in mesa). I have cat deletes and flex fuel tune. I swapped the cats back on, and loaded my catted flex fuel tune. Took about 200 miles to run through the drive cycle to get all my emissions monitors to reset. Just make sure the tune you have keeps the rear o2 sensors in tact or else it might not reset. They walked around with a mirror but I doubt they could really see anything. They do check for the emissions monitor readiness and 4 out of 5 have to be on. I made sure my emissions monitors were ready before I went. I just used a cheap odb2 scan tool and torque pro.

 

[HoosierDaddy]

I had mine tested last week in Scottsdale. They didn't test for emissions at all and didn't do a visual for cats unless they have a glass panel in the lane and someone below ground doing it. The boxes with PASS in them tell you what they checked for.

 

[Shadow277]

As long as no CEL you should be good. Some have mentioned checking readiness monitors but I have not seen that personally here. Plus the no emissions until after 5 years from model year is a plus.

I had an aftermarket cat and I did not pass because the computer read "not ready." Took the tune off and went to stock. I did fine.

 

[Zrussian13]

I had an aftermarket cat and I did not pass because the computer read "not ready." Took the tune off and went to stock. I did fine.
Sounds like your tuner disabled the rear O2s. This is why they never hit ready status and never popped a cel. Used to be popular among Tuners but I don't think most do that anymore.

 

[Shadow277]

Correct. You can get better results in regards to power by doing so.

 

[Zrussian13]

I'm not a tuner but I don't think the rear o2s affect power in the tune. It's more to keep the cel off when guys go catless.

 

[Shadow277]

I'm not a tuner but I don't think the rear o2s affect power in the tune. It's more to keep the cel off when guys go catless.

I was told that quicker calculations can be made with it off. ECUs are not fast so less resources needed could be a feasible explanation.

 

[Zrussian13]

I was told that quicker calculations can be made with it off. ECUs are not fast so less resources needed could be a feasible explanation.

Makes sense. Like I said I'm no tuner. I was always under the impression it was only for keeping cel off and making the Tuners life easy! I'm just happy all my emission monitors show ready and I have no cels. Hopefully no issues when my time comes for emissions!

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