Go Back   DodgeForum.com > Dodge Trucks > Dodge Ram > 2nd Gen Ram Tech
Sign in using an external account
Register Forgot Password?


2nd Gen Ram Tech 1994-2001 Rams: This section is for TECHNICAL discussions only, that involve the 1994 through 2001 Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.

Do downstream o2 sensors effect gas milage?

Reply
 
 
 
 
Thread Tools Search this Thread
  #1  
Old 03-09-2011, 09:23 AM
95gaser360 95gaser360 is offline
Professional
Garage is empty, add now
 
Join Date: Jan 2011
Posts: 125
Default Do downstream o2 sensors effect gas milage?

98 ram 1500 5.2l 2wd. check engine lights come on every week or some after city driving and its always the o2 sensor so my question to you is does the downstream o2 sensor effect gas milage because ive heard its only for emmissions is this true?
This ad is not displayed to registered and logged-in members.
Register your free account today and become a member on Dodge Forums!
Reply With Quote
  #2  
Old 03-09-2011, 09:35 AM
zman17's Avatar
zman17 zman17 is offline
Section Moderator
Dodge Forum Moderator
2000 Dodge Ram 2500
 
Join Date: May 2008
Vehicle: 2000 2500HD 4x4 5.9
Location: NH
Posts: 18,729
Default

That is correct. You can try this to eliminate the CEL. http://dodgeforum.com/forum/2nd-gen-...converter.html
__________________
2000 2500HD 4X4 5.9 and 4:10's,HF tuned SCT,Red-Head gear box, HS 1.7's,
50mm Fastman TB, Hughes Plate,2" Hell Bent ,Volant CAI
Flowmaster 50 series, Rock Solid Ram Steering fix,B&M trans cooler,fuzzy dice good for 5HP
Reply With Quote
  #3  
Old 03-09-2011, 11:47 AM
HammerZ71's Avatar
HammerZ71 HammerZ71 is online now
Administrator
Dodge Forum Administrator
Garage is empty, add now
 
Join Date: Jul 2007
Vehicle: 2014 2500 CTD 4x4
Location: South Georgia/East Florida
Posts: 23,854
Default

Unlike upstream O2s, downstream O2s have no bearing on gas mileage, A/F ratio, etc. It is simply a CEL that comes on to tell you that the cat is not doing the job it is supposed to.
__________________

Photo homage of my beloved old truck. Sold 8/2014
New ride: 2014 2500 CTD 4X4
Reply With Quote
  #4  
Old 03-09-2011, 03:32 PM
95gaser360 95gaser360 is offline
Professional
Garage is empty, add now
 
Join Date: Jan 2011
Posts: 125
Default

but like you said it is telling the computer that the cat is not doing its job. well dont you get bad gas milage if your cat is bad?
Reply With Quote
  #5  
Old 03-09-2011, 03:46 PM
zman17's Avatar
zman17 zman17 is offline
Section Moderator
Dodge Forum Moderator
2000 Dodge Ram 2500
 
Join Date: May 2008
Vehicle: 2000 2500HD 4x4 5.9
Location: NH
Posts: 18,729
Default

Well all kinds of things happen if the cat is clogged. But that has nothing to do with your question about the post cat o2 sensors. Which has already been answered. And from what I've read here, you have no cat(s) anyway. And since gutting the cat will usually result in a loss of low end, you may be on the gas harder to get the truck rolling. Which in turn, will result in worse mpg.
__________________
2000 2500HD 4X4 5.9 and 4:10's,HF tuned SCT,Red-Head gear box, HS 1.7's,
50mm Fastman TB, Hughes Plate,2" Hell Bent ,Volant CAI
Flowmaster 50 series, Rock Solid Ram Steering fix,B&M trans cooler,fuzzy dice good for 5HP
Reply With Quote
  #6  
Old 03-10-2011, 08:55 AM
95gaser360 95gaser360 is offline
Professional
Garage is empty, add now
 
Join Date: Jan 2011
Posts: 125
Default

no i still have a cat on my truck
Reply With Quote
  #7  
Old 03-10-2011, 09:46 AM
jasonw's Avatar
jasonw jasonw is offline
Site Moderator
Dodge Forum Moderator
2010 Dodge Dakota
My Garage
 
Join Date: Jan 2008
Vehicle: 2010 Dodge Dakota 4x4 Quad Cab
Location: Sioux Falls, SD
Posts: 8,249
Default

A CEL about the downstream O2 usually means one of two things.

1. The catalytic converter is bad, which doesn't necessarily mean its clogged, but it may be.
OR
2. That O2 sensor is bad.

Like others have said, a bad downstream O2 will not have any effects on performance/MPGs, but you are right that a bad catalytic converter may.
Reply With Quote
  #8  
Old 03-10-2011, 10:22 AM
HammerZ71's Avatar
HammerZ71 HammerZ71 is online now
Administrator
Dodge Forum Administrator
Garage is empty, add now
 
Join Date: Jul 2007
Vehicle: 2014 2500 CTD 4x4
Location: South Georgia/East Florida
Posts: 23,854
Default

Quote:
Originally Posted by 95gaser360 View Post
but like you said it is telling the computer that the cat is not doing its job. well dont you get bad gas milage if your cat is bad?
Sure a clogged cat will effect gas mileage, but that wasn't the question...
__________________

Photo homage of my beloved old truck. Sold 8/2014
New ride: 2014 2500 CTD 4X4
Reply With Quote
  #9  
Old 03-14-2011, 09:39 AM
95gaser360 95gaser360 is offline
Professional
Garage is empty, add now
 
Join Date: Jan 2011
Posts: 125
Default

how do i tell if my cat is bad?
Reply With Quote
  #10  
Old 03-14-2011, 09:59 AM
HammerZ71's Avatar
HammerZ71 HammerZ71 is online now
Administrator
Dodge Forum Administrator
Garage is empty, add now
 
Join Date: Jul 2007
Vehicle: 2014 2500 CTD 4x4
Location: South Georgia/East Florida
Posts: 23,854
Default

replace the O2, clear the CEL. If the CEL comes back then in all probability you have a bad cat...
__________________

Photo homage of my beloved old truck. Sold 8/2014
New ride: 2014 2500 CTD 4X4
Reply With Quote
Old 03-14-2011, 09:59 AM
 
 
 
Reply




Thread Tools Search this Thread
Search this Thread:

Advanced Search

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

Forum Jump

Join DodgeForum
Advertising

Featured Sponsors
Vendor Directory
Our Sponsors
All times are GMT -4. The time now is 09:48 AM.

Internet Brands, Inc.


Contact Details & Emails