CA 02', how would downstream sensor know if

[Majindan]

I cut the stupid second catalytic converter off?? It's after the primary CAT and before the 2nd one? Why does CA have to be such a pain in the ass and make so many cars adaptive to their countries laws?

 

[4racer]

You have to pass both the sniffer and visuals in CA. However, anything after 01 is now just OBD2 pass and visuals. If you're not throwing a CEL, then you should be okay to pass the OBD2 scan. However, depending if someone nails you for the second cat during visuals.

 

[phattyduck]

It'll never know. You can cut the second cat off without the ECU knowing. It probably isn't costing you any horsepower though.

-Charlie

 

[phattyduck]

You have to pass both the sniffer and visuals in CA. However, anything after 01 is now just OBD2 pass and visuals. If you're not throwing a CEL, then you should be okay to pass the OBD2 scan. However, depending if someone nails you for the second cat during visuals.

He's in TN... no issues with CA smog checks there.

-Charlie

 

[4racer]

He's in TN... no issues with CA smog checks there.

-Charlie

Wups. My bad.

 

[Majindan]

P0420 code is active. Denso rear O2 arrives tomorrow, rear cat looks cashed. Front cat is new, front sensor is new and Denso.

 

[gamefreakgc]

I cut the stupid second catalytic converter off?? It's after the primary CAT and before the 2nd one? Why does CA have to be such a pain in the ass and make so many cars adaptive to their countries laws?

Try living in CA and passing smog

You might get a check engine light. The first cat is considered a "pre-cat" and may not adequately convert all of the combustion gases like the rear one does. If not, what will happen is the rear O2 will read the extra fuel and air and mess with the air/fuel ratio going into the engine. If it fluctuates enough it'll throw a check engine light.

P.S. I live in CA and only have one cat on mine

 

[Majindan]

Try living in CA and passing smog

You might get a check engine light. The first cat is considered a "pre-cat" and may not adequately convert all of the combustion gases like the rear one does. If not, what will happen is the rear O2 will read the extra fuel and air and mess with the air/fuel ratio going into the engine. If it fluctuates enough it'll throw a check engine light.

P.S. I live in CA and only have one cat on mine

Right, but does the rear O2 actually have anything to do with the last cat? If it's bad, would my ECU know or should I just have it sawed off and replaced with straight pipe if it starts rattling or gets clogged? I'm convinced my rear O2 is causing the CEL, I'll know in a couple days.

 

[gamefreakgc]

Right, but does the rear O2 actually have anything to do with the last cat? If it's bad, would my ECU know or should I just have it sawed off and replaced with straight pipe if it starts rattling or gets clogged? I'm convinced my rear O2 is causing the CEL, I'll know in a couple days.

No it's not directly related to the cat, but rather indirectly. The O2 will still function perfectly with a straight pipe, I guess what I'm getting at is if you replace the rear O2, remove the rear cat with a straight pipe, just be prepared to have to mess with the O2 and put in a simulator or something.

 

[Majindan]

No it's not directly related to the cat, but rather indirectly. The O2 will still function perfectly with a straight pipe, I guess what I'm getting at is if you replace the rear O2, remove the rear cat with a straight pipe, just be prepared to have to mess with the O2 and put in a simulator or something.

But why? That's why I'm asking how does the rear O2 obtain any readings for the back CAT as the sensor is bolted in before it, not after.

 

[gamefreakgc]

But why? That's why I'm asking how does the rear O2 obtain any readings for the back CAT as the sensor is bolted in before it, not after.

Wait, yours is before it? Are you sure? If it is that's not stock, the are built from the factory to be after the rear cat.

 

[Majindan]

Ugh, I'm retarded. Downstream IS after 2nd CAT. Sorry. Will a universal cut and weld CAT work for a CA emission based truck? They only test gas cap and OBDII here in Chatt.