Troubleshooting fuel mixture - Focus Fanatics
Focus Fanatics Ford Focus Forums
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace



Go Back   Focus Fanatics > Ford Focus Tech Discussions > General Technical Chat

General Technical Chat This section is for technical discussions relating to general maintenance, electrical issues, engine trouble, and recalls.

Search This Forum | Image Search | Advanced Search    
FocusFest Ford Focus Tire & Wheels FocusFanatics Merchandise

Reply
 
Thread Tools Display Modes
Old 11-07-2012, 06:44 PM   #1
Farking_farkus
Focus Rookie
 
Join Date: Jan 2012
Fan#: 93893
Location: Indiana, IN
What I Drive: 2003 wht LX

Posts: 2
FF Reputation: 1 Farking_farkus Good Standing Member
Buy-Sell-Trade Rating: (0)
Troubleshooting fuel mixture

I have a P0420 code (insufficient cat efficiency) and am trying to isolate the problem. Car idles, drives fine. I do hear very slight emission backfire at 40-50 mph, but hardly can hear it over the radio. I replaced wires, plugs, coil pack recently, and I'm gonna check the injectors tomorrow (with ohmmeter). I think the fuel mix may be a tad rich. Any other suggestions? From what I've read, the O2 sensor is usually not an issue.

http://www.obd-codes.com/p0420


__________________
'03 Silver SE 155K SOHC
Farking_farkus is offline  
    Reply With Quote
Sponsored Links
Advertisement
 
Old 11-07-2012, 07:19 PM   #2
6SPD_soul
Focus Addict
 
6SPD_soul's Avatar
 
Join Date: Feb 2008
Fan#: 53637
Location: Soldiers Grove, WI
What I Drive: 2003 Comp Orange EAP SVT

Posts: 1,468
FF Reputation: 24 6SPD_soul Great Standing Member
Buy-Sell-Trade Rating: (1)
It might be more likely that your cat is just no longer doing it's job. You saw from that site you listed that the front sensor should fluctuate fairly quickly between 0-1V (actually more like .2ish-.8ish) DC and the rear should have a pretty steady and consistent reading of .5V DC. This can be pretty easily checked with a voltmeter/multimeter, but you'd need a wiring diagram to tell which wires to backprobe at the o2 sensor connectors. Two will have to do with the heater circuit and the other 2 will have to do with the signal the PCM is looking at.

I think this would be best way for the average guy to look at what the o2 sensors are doing. There're probably youtube videos that'd show you how to do this.
6SPD_soul is offline  
    Reply With Quote
Old 11-08-2012, 06:46 AM   #3
zetecDon
Where am I?
 
zetecDon's Avatar
 
Join Date: Feb 2009
Fan#: 62506
Location: east of Cincinnati, Ohio, OH
What I Drive: 02 ZX3, 02 MX-5

Posts: 6,837
FF Reputation: 28 zetecDon Great Standing Member
Buy-Sell-Trade Rating: (44)
Moved to "General Technical Chat".
zetecDon is offline  
    Reply With Quote
Reply

Bookmarks & Social Networks

Thread Tools
Display Modes

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


All times are GMT -5. The time now is 04:29 PM.


Copyright 2002-2014 FocusFanatics.com. All Rights Reserved : Terms of Use : Privacy Policy : Advertise Information : Site Map

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Acura TLX. You can find all Ford Focus related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area.