P0420 w/ Catless Mids

tank86

tank86

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My truck threw this code for the first time. I have catless Mids, and it is tuned by Torrie. Could this be for the front 02 sensors? I have a set of Bosch 02 sensors stashed away. Just wondering if I need to get a new tune or replace the front sensors? I appreciate any helpful (or sarcastic) input in advance!!!
 
I mainly need to know if this is a tune problem or 02 problem.

I have a feeling the general consensus is to contact Torrie and ask him after researching other threads with the same problems, but was just wondering if anyone else had further experience with this issue.
 
Then your cats are no good most likely.
 
Could still be one of the 2 rear O2 sensors. Has nothing to do with your front sensors. Are your rears still there and plugged in?
And only use Bosch. Not sure what E is talking about? :dontknow:
 
P0420 Catalyst Efficiency Below Threshold Bank 1 The most common thing is the catalytic converter itself is no longer functioning properly. The other likely thing is the rear O2 (oxygen) sensor is no longer working properly. Other things could include exhaust leaks, damaged exhaust pipes, damaged O2 sensor wiring/connectors, plugged catalytic converter, etc. If your Cats are "gutted"(internals removed) You need to remove the rear O2 sensors from the exhaust stream.
JTSVP 02 SENSOR SIMULATORS Check for melted wires...... last thing is to change out the sensors, one at a time , clearing the codes each time.
 
VPRPWRD said:
Then your cats are no good most likely.
Click to expand...

What is the best way to check and diagnose a faulty cat, besides the code?

VENOMOUS1 RACING said:
Could still be one of the 2 rear O2 sensors. Has nothing to do with your front sensors. Are your rears still there and plugged in?
And only use Bosch. Not sure what E is talking about? :dontknow:
Click to expand...

Ok, so we are ruling out front 02 sensors, I believe the rears are removed and bunghole (I giggle everytime I type or read that) are plugged. I will double check when there is daylight.


Slitherbeast said:
P0420 Catalyst Efficiency Below Threshold Bank 1 The most common thing is the catalytic converter itself is no longer functioning properly. The other likely thing is the rear O2 (oxygen) sensor is no longer working properly. Other things could include exhaust leaks, damaged exhaust pipes, damaged O2 sensor wiring/connectors, plugged catalytic converter, etc. If your Cats are "gutted"(internals removed) You need to remove the rear O2 sensors from the exhaust stream.
JTSVP 02 SENSOR SIMULATORS Check for melted wires...... last thing is to change out the sensors, one at a time , clearing the codes each time.
Click to expand...

I do not believe my cats are gutted. Ugh seems like a crap shoot of trouble shooting. This code just started within the last month or so. Never seen it before.

What would be some symptoms to look for in order to widdle this problem down?
 
Best way to check for a blocked catalytic converter is to pull the head pipes & look inside. That's how I found mine. The honeycomb/core was starting to melt & close off.
Went with JMB mid pipe kit to fix it. Also put in 4 new Mopar O2 sensors. After almost 10 years I figured they seen better days.
 
10-1=9 said:
Best way to check for a blocked catalytic converter is to pull the head pipes & look inside. That's how I found mine. The honeycomb/core was starting to melt & close off.
Went with JMB mid pipe kit to fix it. Also put in 4 new Mopar O2 sensors. After almost 10 years I figured they seen better days.
Click to expand...

Since I have BB catted Mids, wouldn't it be more beneficial/cost effective to have the old cats cut out and replacement cats welded in?
 
You would have to price it out. There is also the legality issue with removing them.
 
If the bunghole is plugged ,where are the rear O2 sensers?
 
Slitherbeast said:
If the bunghole is plugged ,where are the rear O2 sensers?
Click to expand...

Hmmm. I hope I am not giving yall bad info. I looked and there is a hole facing outward on the driver's side that appears to be plugged. As to where the sensors actually are.....
 
Ok, I got a pic. Seems easier. So I have 02 sensors BEHIND the cats, and what i think are plugged before the cats.
 

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That was a bunghole for a wideband or something and in a poor location. Never install O2 sensors upside down! All the moisture gets in em and ruins them fast! Like leaded fuel!
You're looking for sensors behind cats not in front of them. Best way would be to find the rear O2 plugs and see if O2s are connected. Even though rear O2 are deleted they need to be connected to plugs just not in exhaust stream. Usually we zip tie then to tranny braces.
 
Found the 02 sensors towards the rear of the cats. Still plugged in and in the exhaust stream. So take them out of the midpipe, plug the holes and secure them somewhere? Will this not throw a code or what?
 
tank86 said:
Found the 02 sensors towards the rear of the cats. Still plugged in and in the exhaust stream. So take them out of the midpipe, plug the holes and secure them somewhere? Will this not throw a code or what?
Click to expand...

Yes fill the holes with plugs and secure them to tranny. Again disconnect battery and clear codes. If you have an SCT clear codes using it. Also if one of those two sensors is legitimately bad your code will come back. Like recommended I'd still check cats or did you?
 
Didn't check cats yet. All this talk made me thinks... I don't have to do emissions inspection... Why the F haven't I gone catless yet?!
 
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