Register Login
endrop - for all your online needs
Reply
 
Thread Tools
Old 29-10-2018   #1
Join Date: Nov 2017
Posts: 21
Thanks: 0
Trader Rating: 0
Sweden 
Is my cat gone? Help interpreting MES graphs.

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? See attached image (RPM: blue line, pre-cat O2 sensor: red line, post-cat: green line).

Thank you in advance
Attached Thumbnails
Click image for larger version

Name:	IMG_1989.jpg
Views:	26
Size:	1,000.2 KB
ID:	195161  
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Cromatic is offline Reply With Quote Quote 
Old 31-10-2018   #2
Moderator
 
g8rpi's Avatar
Join Date: Nov 2013
Location: Cambridge
Posts: 4,021
Thanks: 402
Trader Rating: 0
g8rpi has donated!
United Kingdom 
Re: Is my cat gone? Help interpreting MES graphs.

Quote Originally Posted by Cromatic View Post
<SNIP>


Could this indicate anything else than an upcoming cat replacement? 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?

Robert G8RPI.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

g8rpi is offline Reply With Quote Quote 
Old 30-03-2019   #3
Join Date: Nov 2017
Posts: 21
Thanks: 0
Trader Rating: 0
Sweden 
Re: Is my cat gone? Help interpreting MES graphs.

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. Didnīt know driving with a rich mixture could fudge it up THAT much ...
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

Cromatic is offline Reply With Quote Quote 
Old 02-04-2019   #4
Moderator
 
g8rpi's Avatar
Join Date: Nov 2013
Location: Cambridge
Posts: 4,021
Thanks: 402
Trader Rating: 0
g8rpi has donated!
United Kingdom 
Re: Is my cat gone? Help interpreting MES graphs.

Hi,
At least it's fixed. If the CAT is cracked due to hitting something, the parts can rub together and break up into pieces small enough to es tcape further down he exhaust system.

Robert G8RPI.
__________________
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

g8rpi is offline Reply With Quote Quote 
Reply
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump
Similar Threads
Thread Thread Starter Forum Replies Last Post
(T) Interpreting OBD2 data beeswax Grande Punto 4 29-07-2013 22:54
Excel graphs problems garlicbread22 Computing 2 14-04-2011 16:11
Pop Graphs soopahfly Leisure Lounge 0 05-03-2008 10:59
C&B Cams + UniChip Graphs YoGiS FIAT Boo Archives 14 08-07-2003 20:45