O2 sensor voltage fluctuation wildly - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 09-19-2007, 08:49 PM   #1
Registered Member
 
Join Date: Aug 2007
Posts: 4
Country: United States
O2 sensor voltage fluctuation wildly

I have a 95 geo metro. It has a 4 wire O2 sensor. My millage has not been what I think it should be so I hooked a multimeter and a air/fuel mixture gauge up. The voltage and gauge fluctuate wildly from most lean to most rich. I am sure it is not a loose connection. Does this mean the O2 sensor is bad?

Thanks
__________________

Giovanni is offline   Reply With Quote
Old 09-19-2007, 08:50 PM   #2
*shrug*
 
Join Date: Sep 2005
Posts: 6,195
Country: United States
No, usually narrowband sensors flick back and forth rapidly and the ecu extrapolates a middle point. It's weird but that's how it works.
__________________

SVOboy is offline   Reply With Quote
Old 09-19-2007, 09:05 PM   #3
Registered Member
 
Bunger's Avatar
 
Join Date: Feb 2006
Posts: 311
Country: United States
It could be bad if it's taking a long time for it to "flick" back and forth. The faster it responds the better mileage you'll see.
__________________
Anger is a gift!
- Zack de la Rocha
Bunger is offline   Reply With Quote
Old 09-20-2007, 02:03 AM   #4
Team GasMisers5!
 
landspeed's Avatar
 
Join Date: Nov 2006
Posts: 440
Country: United States
When I had a SuperMID on the Micra, the injector pulse width would fluctuate back and forth, when cruising with a perfectly constant throttle load - again due to the O2 sensor I guess.
__________________

Team GasMisers5 - #1 for first three rounds of the original GS Fuel Economy Challenge
Miles displaced by e-bike since 1 Jan 2008: 62.6 (0 kWh used)
Hypomiler
landspeed is offline   Reply With Quote
Old 09-20-2007, 12:52 PM   #5
Supporting Member
 
cfg83's Avatar
 
Join Date: Sep 2006
Posts: 1,779
Country: United States
Giovanni -

Like SVOboy says, narrowbands fluctuate all over the place. On my Saturn, mine fluctuates up and down all the time, but it seems to cheat from 14.6 and up after the engine's all warmed up. When I am in steady-state cruising, the swing is much smaller, maybe 14.6 to 14.9 most of the time.

EDIT : Correction, the 14.6 to 14.9 is the digital/numeric display sample over a longer time period. So I still see the fluctuation. If I get a chance, I will make a youtube of it.

CarloSW2
__________________
Old School SW2 EPA ... New School Civic EPA :

What's your EPA MPG? http://www.fueleconomy.gov/feg/calculatorSelectYear.jsp
cfg83 is offline   Reply With Quote
Old 09-22-2007, 07:39 AM   #6
Registered Member
 
Join Date: Aug 2007
Posts: 4
Country: United States
Thanks for the replies. I guess that little gauge is useless then so back it goes. I am only getting about 41 mpg out of this car and am stumped. I have changed the plugs, dist. cap, and wires. New filters and all to no avail. Any ideas?
__________________

Giovanni is offline   Reply With Quote
Reply

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Odometer help/suggestion waterboysh Fuelly Web Support and Community News 10 12-14-2012 04:38 PM
Can fuel descriptions associate with mileage at *next* fuel-up? anthill Fuelly Web Support and Community News 2 01-30-2011 11:32 AM
Are Algae the Future of Energy & Biodiesel? Ecacophonix Vegetable Oil and BioDiesel 0 05-16-2007 11:40 AM
Conversion successful Matt Timion Fuelly Web Support and Community News 12 05-18-2006 03:24 PM
Electric panel heaters GasSavers_JustMe General Discussion (Off-Topic) 0 01-03-2006 04:43 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 06:19 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.