[turbotko]

Whoa, lot's of mis information here. The catalyst monitor function is regulated by OBD2 standards and has nothing to do with turbo or N/A. It's very complicated as to how the DME applies the OBD2 logic when running the various OBD2 tests. Oversimplifying it, the DME has to see a problem present over 2 consequetive drive cycles to turn on the CEL, although a fault code will be stored in the DME the first time it runs the test and fails. Also, the DME does not constantly monitor the catalysts, only when driving and other conditions are correct will it run the catalyst monitor. One other note, if the DME see's the problem through 2 consequetive tests it will turn on the CEL, but then later runs the test a few times and doesn't see the problem present anymore it will turn the CEL out.

Has anybody tried any regular old O2 sims like the mustang and F-body guys run when they delete the cats? Although the pre-cat O2 sensors are bosch wideband sensors, the post cat's are regular old .1-.9 volt sensors that have been used forever...........do a little wiring to get the connectors to work and all this catalyst monitor fault thing might go away.

[533ogetnom]

Originally Posted by turbotko

Whoa, lot's of mis information here. The catalyst monitor function is regulated by OBD2 standards and has nothing to do with turbo or N/A. It's very complicated as to how the DME applies the OBD2 logic when running the various OBD2 tests. Oversimplifying it, the DME has to see a problem present over 2 consequetive drive cycles to turn on the CEL, although a fault code will be stored in the DME the first time it runs the test and fails. Also, the DME does not constantly monitor the catalysts, only when driving and other conditions are correct will it run the catalyst monitor. One other note, if the DME see's the problem through 2 consequetive tests it will turn on the CEL, but then later runs the test a few times and doesn't see the problem present anymore it will turn the CEL out.

Has anybody tried any regular old O2 sims like the mustang and F-body guys run when they delete the cats? Although the pre-cat O2 sensors are bosch wideband sensors, the post cat's are regular old .1-.9 volt sensors that have been used forever...........do a little wiring to get the connectors to work and all this catalyst monitor fault thing might go away.

as i said this is just how it was explained to me, i do not know much about emissions systems, but if you are going to say that its a lot of "misinformation" then please feel free to provide YOUR explanation as to why all but why person is not throwing a CEL with deleted cats, i would LOVE to hear it

[turbotko]

Originally Posted by 533ogetnom

as i said this is just how it was explained to me, i do not know much about emissions systems, but if you are going to say that its a lot of "misinformation" then please feel free to provide YOUR explanation as to why all but why person is not throwing a CEL with deleted cats, i would LOVE to hear it

Pump your brakes for a second man......I'm not hate'n on anybody here sheesh. Maybe my explanation was hard to understand, but I was just summarizing how OBD2 runs the catalyst monitor.

Sure, if you don't have cats, sooner or later your gonna get a cat efficiency fault code stored. I was basically saying that it all depends on how you drive the car as to when the fault is stored. And also that just because there is no C/E light doesn't mean there isn't a fault stored in the DME. Prevent the car from going through the OBD2 drive cycles and it will never run the catalyst monitor and never throw a C/E light. Hell, I went 7 months with my 01 cobra with no cats before I finally got a C/E light.......but that's because I drove that car at WOT pretty much all the time. :rocks:

[andrew20195]

To expand upon what Turbotko is saying, the computer requires specific conditions to be met in order to run the Cat. monitor. Typically this requires steady cruise at over 50 mph with the engine at full operating temperature for 5-10 minutes. The first time a Cat. inefficiency is detected, a temporary code is stored. In order for the CEL to be triggered, the Cat. monitor must fail a second consecutive time, otherwise the temp code is cleared. This is how the system works for both NA and turbo applications. In other words, it depends on driving habits. Also, if you're running aftermarket cats, it is possible that they could be just on the threshold of acceptable efficiency, and would give an intermittent CEL, as the monitor would not always fail two times consecutively.

I am somewhat surprised that the vehicle enters limp mode for Cat. codes, however. Admittedly, most of my technical experience is on NA cars, but usually limp mode is only triggered for problems that immediately affect engine operation, e.g. primary o2/AF sensors failing.

There are a few ways to prevent Cat. codes from occurring. One way is to find some "Spark Plug Anti-Foulers" that have the same threads as the secondary o2 sensors. Install one in the pipe. Drill out the end of a second one (to use as a spacer), thread it into the first one. Finally, install the o2 sensor into the second. It has the effect of limiting exhaust gas exposure on the second sensor, which in turn "smooths" out the A/F fluctuation that causes the Cat. monitor to fail. On some cars this is not possible due to tight clearance between the sensor, exhaust, chassis, etc. The other way is (as previously mentioned), using an electronic o2 sensor emulator that returns the voltage values the computer expects to see.

@rideelement247: No, setting a CEL does not void your warranty. If you take your car to a dealer with aftermarket DP's, Cats, etc., expect to pay a diagnostic charge. Those parts (and any resulting CEL's) will definitely not be covered by warranty. Your best bet is to get a code reader so you can clear the codes if they are related to your aftermarket parts.

[533ogetnom]

wait wait wait....

this is funny

so you basically said im wrong ( or rather the dude i talked to) but that im actually right? good job

[andrew20195]

Originally Posted by 533ogetnom

wait wait wait....

this is funny

so you basically said im wrong ( or rather the dude i talked to) but that im actually right? good job

Why do you take everything as a personal attack?

...as i said this is just how it was explained to me, i do not know much about emissions systems...

I was explaining exactly how the system works for your benefit (as well as everyone else here).

Your friend arrived at the correct conclusion, but his reasoning behind it was flawed.

[533ogetnom]

i wasnt actually talking to you, i didnt say what i said about the difference between NA and turbo engines was not what you said was the same

you were essentially correcting... no one