i've got an 03 cavi and i had cut out the cat and tried to make my exhaust as free flowing as possible (header, 2.5" piping all the way to a can muffler, nothing in between) the only problem i had with this was that horrible light that came on with the check engine sign............. until now. i know alot of people have used o2 sims from companies that mass produce them and they either work for a little while or not at all. Well i had gotten an o2 simulator that was made for a late model z28 camaro with an ls1 but the plug was the flat kind not the square that i had needed. So i took the plug that goes from the plug over my tranny to the rear o2 sensor. i played around trying to match some colors but finally got it right and basically chopped the plug off and wired in the simulator. i've driven over 150 mi for about 5 hrs and still no check engine light. i just wanted to let people know this because i've seen dozens of strands about people who have chopped off their cat and needed an o2 sim and nothing worked right.




If it's too loud, you're too old!!

you will get horrible gas mileage and actually less performance without a car then you will with a highflow unit from Carsound. Order a 2.5" (to match the rest of your piping) Carsound cat and I promise you will pick up a bit more power on your low end.


I was a retard, and now I'm permanently banned.

The gas mileage doesnt go that bad. Ive been running no cat for a year now with an O2 sim from caspers electronics. You might want to get the proper simulator for your car so nothing goes wrong.

The down side is your check engine light is no longer a good indicator of when things are going wrong. The first thing that happens when something goes wrong is usually the air/fuel ratio goes to hell. With an O2 sim you will never know because it is set to make the ecu think your ratio is always fine. I personally am going to a 2.5 magnaflow high flow obd II compliant cat. This will allow the cars air/fuel ratio to be corrected because right now I am running rich and can constantly smell unburned gas from the exhaust. The only way to fix that is to have the second O2 sensor plugged back in.

The simulator is not for the A/F ration. You use the simulator for the 2nd sensor witch is for emission purpuse only. Thanks OBDII. It doesn't affect the A/F ratio. it only tell the Ecm that your "cat" is working good but there's no cat. Only the first O2 sensor will work for the A/f ratio.



Gilles
2.3 Ho

Mfk-223 wrote:The simulator is not for the A/F ration. You use the simulator for the 2nd sensor witch is for emission purpuse only. Thanks OBDII. It doesn't affect the A/F ratio. it only tell the Ecm that your "cat" is working good but there's no cat. Only the first O2 sensor will work for the A/f ratio.

Correct. Has no effect on your A/F ratio.

it should be obvious considering when you wire up an A/F gauge the only o2 sensor wire you tap into is the sensor in the exhaust manifold...


I was a retard, and now I'm permanently banned.