Technical Is my cat gone? Help interpreting MES graphs.

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Technical Is my cat gone? Help interpreting MES graphs.

Cromatic

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No, this thread is not about a runaway feline...but first some backstory:
About a year ago, I noticed that the Croma (2.2 liter petrol, shy of 130 000 km on the odometer) was running rich and it turned out to be a leaky fuel injector which I have since replaced. However, it might have gone too long running rich, which I suspect have damaged the catalytic converter.

It now throws a P0420 error, catalytic converter efficiency below threshold. I have cleared it and it comes back. I graphed the pre- and post-cat O2-sensors (at idle and 2500 rpm, warm engine) and it looks like the post-cat sensor oscillates in tune with the pre-cat sensor, which is a bad sign right, should be flatlining?

Could this indicate anything else than an upcoming cat replacement:bang:? See attached image (RPM: blue line, pre-cat O2 sensor: red line, post-cat: green line).

Thank you in advance
 

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Could this indicate anything else than an upcoming cat replacement:bang:? See attached image (RPM: blue line, pre-cat O2 sensor: red line, post-cat: green line).

Thank you in advance

Hi,
I'm no CAT expert but I think you will be needing a new one. Does it put warning ligth on the instrument cluster?
Schrodingers emissions test?
wink.gif


Robert G8RPI.
 
Quick update: hade the cat changed yesterday. The inside of the old cat was - gone. Completely devoid of the honeycomb structure, just an empty can. Probably went out the tailpipe somehow. Didn´t know driving with a rich mixture could fudge it up THAT much :confused:...
 
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