Well obviously this would probably be better to ask on a different forum but i figured some of you RX8Clubbers could help shed some light on this! plus i dont want to have to join a mustang forum .

So my friend has a 2007 Supercharger Mustang GT California Special, he is not a big car guy, its just what his dad bought him and he drives it like its any other car. He has had problems with passing inspection for a few reasons but none that make to much sense to me.

So apparently he has a faulty O2 sensor which is throwing his check engine light off, problem one. Not too big of a deal, i figured dropping in a new O2 sensor would take car of that. The main problem is something going on with him either not having a cat or having problems with his cat.

He failed emissions testing and the shop told him it was because he does not have a catalytic converter, but his exhaust doesnt smell like it should if he were catless. And the Ferrari dealership told him that he has a very small hairline crack in his exhaust, and didnt mention anything about him not having his cats.

So could a faulty O2 sensor be the reason for failing his emissions testing? I thought a faulty O2 sensor will only through off the CEL and not effect emssions but then again im not 100% sure about that.

Any help is greatly apprecaited!

 

hid O2 is fine.

He failed due to lack of Cat

 

but why wouldnt his exhaust smell like he is running catless?

 

A piston engine doesn't smell like a rotary ....even catless

He won't pass emissions without a CAT...and obviously a mechanic that has a clue

 

Haha yeah I know it won't pass without a cat. Just didn't know it wouldn't smell the same as my cat less rotary

You can always learn something new on here! Thanks.

 

Chances are he does not have a cat. However if he does, and the o2 sensor has been bad for a long time, the cat could be ruined form the engine burning the wrong AFR for too long.

 

An odorless exhaust at idle is not specific to a piston powered car or a rotary powered car. It's a matter of tune. You could stand behind our 4 rotor Kudzu race car back in the day without the fuel fumes and dizzying effects. Quite clean.

Back to the problems of the OP: Most modern emission tests rely on DTCs (Diagnostic trouble codes) , the absence of which would provide a passing grade. However, the visual inspection part requires the presence of a converter even if the car was putting out 0 pollutants into our atmosphere without it.

Paul.