LMAO

"stoichiometric monitoring" is meaning the actual air/fuel mixture. Air/fuel mixture needs to be about 14.7-1. When it is out of range the mixture will not fire. During combustion you need the right mixture meaning air/fuel and a detonation. A perfect combustion mixture is about 14.7-1. This is stoichiometric .

So what I'm saying is, the members O2 sensor isn't reading the mixture in the exhaust correctly, thus not correcting the air/fuel mixture to get it to the correct mixture, thus meaning a bad pre-cat O2 sensor.

 

i say that my durango don`t have CAT and don`t have poblem. (check engine)

 

i have heard that if the post cat 02 is zip tied into the frame rail it will still read as if the cat is there, but iv never see it done or tried it myself

 

my be! my friends say me that when no CAT second O2 have no correct data and ECU used another stoichiometric map.

 

HUH?! The Post-CAT O2 sensor does not use data to affect air/fuel mixture it is only to monitor CAT performance.

 

Yep!

The post CAT sensor (after CAT) does nothing for the mixture. It only verifies that the CAT is working correctly, and that is all. Only the pre-CAT sensor indicates heat and mixture.


+1 Sharps,

I would assume that zip tie'ing the post CAT O2 sensor to the frame would not trigger a code because it would not be sensing any particles, thus resembling that everything was working fine after the CAT. If it where me though, I would encase it in something to keep the end from getting moisture on it.

 

Ok! That doing ecu when cat does not working?

 

There is no ECU in Dodge, the main computer is called the PCM, but I get your question.

When the Catalytic Converter is plugged or bad the pre-O2 sensor would not throw a code. Now if you have a after CAT O2 sensor it might show a code because the CAT isn't working properly, however it might not throw a code if it is just plugged. Now if it is bad then it would throw a code to indicate that there is something wrong with the CAT.

Basically, if the PCM registers an error then it will throw a code, if not it wont.


In comparison, the CAT in my truck is plugged or I have a plugged muffler. Either way I have a partial blockage, but no code has been tripped because I do not have a after CAT O2 sensor to tell me there is a problem. The inputs from my truck tell the PCM that there is no problem, however I know there is a problem because of lack of performance and my fuel mileage went to hell especially when towing or at higher speeds.

One way to find out if your CAT is plugged or muffler is to have a muffler shop do a pressure test. They can test the pressure before and after the CAT and also the muffler to find the problem. most shops will do this for free because they want to sell you products, however you do not need to buy them.


So a conclusion to your question, the PCM would hopefully get a code (CEL) telling it that there is a proplem, but really nothing else. Your fuel mileage will suffer and your power will go out the window because the PCM is getting incorrect or bad signals.