LexBrett

Just got my car back today with ppe headers installed and a third cat delete. To my surprise the CEL came on with a p0420 code, which is something about the catalytic converter. Since I didn't touch the primary cats where the O2 sensors are housed, what could be going on? The O2 sensors were fine before the install. Any advice is greatly appreciated

bacardi11

iTrader: (1)

lex
disconnect the battery 10 min to reset. let us know I had no problem with third cat. del. how's the car run.

LexBrett

Car runs bad ***. More power through the entire rpm range, both high and low. I reset the code. I think my o2 sensors are old and confused by the new airflow. I may put some O2 spacers and maybe replace the sensors themselves. I'm just dissappointed to get a CEL..

tmf2004

iTrader: (15)

can you post a video?

bacardi11

iTrader: (1)

failed inspection last week I just replaced passenger side sensor then passed inspection. do not use spacers. you don't have to replace sensors if no light. that happen when you reset it light out.

bacardi11

iTrader: (1)

I new you would like it.

LexBrett

So you think the CEL is just due to the old O2 sensor and it's not a big deal?

FlopTop04

Actually, the front O2 sensors are mounted in the headers and the rear O2 sensors are mounted in the rear Y pipe with the 3rd CAT. The front CAT's don't have the O2 sensors.

P0420 can typically be caused by 3 things : an exhaust leak, a bad O2 sensor or a bad CAT.

Due to the recent work on your SC, I would check / listen for a leak and verify the harness to the driver side front O2 sensors is connected at the junction ( engine compartment ) with no harness / pin damage. Also check the driver side rear O2 sensor harness.

Not sure how you effected the rear CAT delete, but if that sensor was removed and re-installed like the front sensors, then it's possible they were damaged. A good Scan Tool with real time O2 readouts will help define the problem

LexBrett

Thanks- I have an O2 scan tool, but what should I be looking for? Also, according to diagrams I have seen the third cat is after the o2 sensor so a third cat delete could not effect that sensor?

FlopTop04

Depending on how the 3rd CAT was deleted. If they just cut it out and welded a piece of pipe in its' place, then the rear O2's might not have been touched . From the factory, it's one long Y pipe with a CAT after they join into one pipe, but it is one welded piece and the CAT does not have conventional flanged ends.

With the P0420, it's saying the drivers side, so compare the readings from one side to the other, both front and rear O2's. A bad sensor won't fluctuate like the others. Might be a YouTube video on it somewhere.

LexBrett

They cut out the third cat. It's actually two codes: P0420 and P0430, so I guess it is both sides. Should I monitor the O2 readings on my scanner, and look if the voltage is between .2 and .9? I looked at several websites, and it could be a variety of things in addition to the 02 sensor. Makes sense given the extensive install. I hope my shop can figure it out at no cost. If not my first inclination is to install O2 spaces myself..

SlvBullet

iTrader: (8)

Brett - what happened after you disconnected the battery? Sis you get the cel aga in right away or after driving a bit? I didn't have any cel after my PPE install and 3rd cat delete.

Good luck

SlvBullet

iTrader: (8)

Sounds dumb but just in case check to make sure your installer actually fully connected the sensor wires and that the connectors are tight. #>^***}^# happens ....

LexBrett

I didn't check the connections but the light didn't come on right away. I reset the code and drove the crap out of it and the cel hadn't come back yet..

bacardi11

iTrader: (1)

you seem like a happy camper