O2 sensor replacement?

russellcframe · 08-06-2003, 12:06 PM

I just looked up the O2 sensor and it's about $120 from NAPA for my '95 4Runner 3.0.

So what exactly does that get me?

Is it really a required or even worthwhile replacement?

I'm getting 17mpg now, will that increase significantly?

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mtnfreak · 08-06-2003, 12:25 PM

Check your owner's manual. Toyota does replace some of them for free at 80K miles.
I'm sure someone here can detail the procedure for checking to see if your's is bad or not. It's real simple on the '89s.
$120 sounds about right for the NAPA part, but I've heard of many people switching back to the OEM sensor for a variety of reasons.
17mpg is about right for a 2-ton vehicle with the 3.0. You might see some improvement with a new sensor, but don't expect to be breaking into the 20's.

Bumpin' Yota · 08-06-2003, 09:23 PM

I just swapped out mine. Already have seen a slight improvement in milage but a noticable loss of power as the engine was running rich before. Im going to wait 2-3 tanks before I come to any conclusions though. A mechanic told me that the ECU would fully reset to the new O2 sensor after about 60 keystarts.....thoughts?

My freak-of-nature-3.0 just broke into 20-21mpg on this last trip home. Got 165 miles on 1/2 tank doing 70mph, I'll know exact numbers when I fill up again. (no racks, no big tires, 4.11 gear, 50psi, no gunning, no hills, the FL norm...)

Hope for 20, but as the previous poster stated, don't expect it. Most 3.0s seem to be lucky to get 17....

russellcframe · 08-07-2003, 06:57 AM

Forgive my ignorance, but if the fuel economy might only be mildly affected (Not enough to warrant $120 and time to install)....what is the point in changing it at all? I know it's a periodic maitenance item....I just don't understand why (unlike fluids and lubricants that wear down and can decrease component life if not changed regularly).

Thanks,
Russ

TOR · 08-07-2003, 07:11 AM

O2 sensor, shipped to your front door for $89.26. Some parts you might be able to get away with subbing out at after market stores but I wouldn't do it with 02 sensors. Actually I don't recommend it at all but thats just from what I see everyday from those that do. If you are interested let me know.

Todd

russellcframe · 08-07-2003, 07:13 AM

Sounds like a pretty good price.

Can you answer my question about "why" someone should change it in the first place?

mtnfreak · 08-07-2003, 07:17 AM

O2 sensors don't really 'wear out', but they do corrode - the exhaust stream is a nasty place to be. Some of the material in the sensor may even be sacrificial(sp?).
Still hoping someone can post the test procedures for your '95.

russellcframe · 08-07-2003, 07:19 AM

I don't mind replacing something if it's needed and beneficial, just don't want to do it for no good reason

Thanks again,
Russ

Bumpin' Yota · 08-07-2003, 07:46 AM

Quote:

Originally posted by russellcframe
Forgive my ignorance, but if the fuel economy might only be mildly affected (Not enough to warrant $120 and time to install)....what is the point in changing it at all? I know it's a periodic maitenance item....I just don't understand why (unlike fluids and lubricants that wear down and can decrease component life if not changed regularly).

Thanks,
Russ

Here is my thought train on the matter. It's probably incorrect, and if so, someone correct me.

When the O2 sensor goes dead, the ECU for whatever reason seems to make the engine run very rich. (Lack of O2 in the exhuast indicating lean conditions?) Doing this for a long period of time makes the injectors fire off the most fuel they can, meaning really loud injector noise. I don't know if the injectors would fail after a while, but them going wide arse open can't help their life expectancy and it certainly wouldn't help in keeping them clean....

Then I heard something about a rich exhuast killing/clogging catalytic converters....

Besides, if you plan on keeping your yota for a long period of time, it should pay for itself.

Steve

MTL_4runner · 08-07-2003, 08:04 AM

Quote:

Originally posted by russellcframe
Sounds like a pretty good price.

Can you answer my question about "why" someone should change it in the first place?

I replaced mine because it made my check engine light come on at about 81K mi. At that point it began to run real rough and hesitated quite a bit. I think (guessing here) when the O2 sensor is out of spec, the ECU just disregards the signal and relies on the MAF, TPS and the preprogrammed fuel curve in the Eprom chip. The lack of an O2 signal just doesn't give the ECU a feedback to correct for.

It is also the main reason why I have my OBD II code reader from www.Auterraweb.com .....I love it!

After replacing it my truck runs ike a million bucks again, but mine was bad enuf to set off the engine light tho.

mycotopian · 08-08-2003, 10:29 AM

Can you just clean the o2 sensor and see any improvements??

MTL_4runner · 08-08-2003, 06:23 PM

Quote:

Originally posted by mycotopian
Can you just clean the o2 sensor and see any improvements??

I don't think so since it has a special coating on it but I could be wrong......if it were me I wouldn't chance it and just pay up for anew one.

TOR · 08-09-2003, 08:00 AM

Yeah cleaning it will do no good just get ya a new one.

Todd

KevyWevy · 08-09-2003, 09:57 AM

yeah so how do you know if its bad? other than having the check engine light on? i just bought my 4Runner about 4 months ago and don't have any maintanace records.

mynameisjonas · 08-09-2003, 03:13 PM

Quote:

Originally posted by TOR
O2 sensor, shipped to your front door for $89.26. Some parts you might be able to get away with subbing out at after market stores but I wouldn't do it with 02 sensors. Actually I don't recommend it at all but thats just from what I see everyday from those that do. If you are interested let me know.

Todd

that is a good price, where could i get one for that? and is that one just a plug in, no splicing required?

MTL_4runner · 08-09-2003, 04:14 PM

Quote:

Originally posted by mynameisjonas
that is a good price, where could i get one for that? and is that one just a plug in, no splicing required?

Dude, that is a smokin' price....I forget what I got ripped off for at the stealership but way more than that.

MTL_4runner · 08-09-2003, 04:18 PM

Quote:

Originally posted by KevyWevy
yeah so how do you know if its bad? other than having the check engine light on? i just bought my 4Runner about 4 months ago and don't have any maintanace records.

It is not fun.....don't burn yourself.

You need to probe it hot (ie car warmed up) with a DMM and see if it is still within the specs.

or......you can do what I did and get the OBD palm device from www.Auterraweb.com and look at the sensor voltages while driving. There are other OBD devices out there that I think will do similar but I don't have any of them so I can't speak to it.

KevyWevy · 08-09-2003, 05:05 PM

what is a DMM and where do i get it? im just trying to help out my gas milage a little.

MTL_4runner · 08-09-2003, 05:11 PM

Quote:

Originally posted by KevyWevy
what is a DMM and where do i get it? im just trying to help out my gas milage a little.

Sorry Digital Multi Meter......any hardware place or good auto store should have one. Even the cheap ones do quite a bit (got one for $10 at Walmart). You just need the basic stuff, volts, amps, ohms, diode test, continuity......capacitance is nice to have but usually much more $$$

KevyWevy · 08-09-2003, 05:27 PM

and what i just look in the owners manual and look at how many volts are going throught it or something?

MTL_4runner · 08-09-2003, 09:07 PM

Quote:

Originally posted by KevyWevy
and what i just look in the owners manual and look at how many volts are going throught it or something?

The owners manual won't even tell you where your spark plugs are.......you need a decent repair manual to follow.....go to the fuel section of it and it will tell you the correct proceedure for testing them and exactly what to look for (ie what are "good" and "no good" conditions for each component). You will need your new DMM to do any of this type of testing tho.

Bumpin' Yota · 08-12-2003, 04:22 AM

Back up to 21.8 mpg........

russellcframe · 08-12-2003, 02:45 PM

Hey Bumpin Yota...

About that 21.8...I take it your mpg went up a lot with an O2 sensor replacement. What were you getting before and did you change anything else for that improvement or do you think it was all about the sensor?

Thanks.

Bumpin' Yota · 08-12-2003, 03:49 PM

Quote:

Originally posted by russellcframe
Hey Bumpin Yota...

About that 21.8...I take it your mpg went up a lot with an O2 sensor replacement. What were you getting before and did you change anything else for that improvement or do you think it was all about the sensor?

Thanks.

Well that 21.8 was highway driving @ 70mph, before I was getting about 19 at that speed, so it was roughly a 3mpg increase. Im hoping for more of an increase as the ECU fully adjusts.

I'm on course to get roughly 17-18mpg around town revving the engine at every light. Still not as powerful as I'd like, but it's getting much better milage thankfully.

Steve

**4x4Fink** · 09-30-2003, 08:08 PM

Don't mean to bring this post back from the dead but...I am having serious mileage problems.

I am getting ~10.8-11.2 MPG city...thats with my lead foot and ECT part of the time. I am thinking it is either a bad 02 sensor, bad AFM (Air Flow Meter, thanks to robinhood) or a clogged cat.

There is a pretty bad smell that comes after I rev the engine a little. The smell isn't constant though, usually only after running the engine for a little bit. It is acting like the 02 sensor is about to go bad...I am thinking I should take it to the shop and have them check everything out. What do you all think? Any of you that know me and my lack of skills should know that I am probably not capable of doing any of the diagnosing myself...

Comments/Questions?

Thanks,

Fink

08-06-2003, 12:25 PM	#2 (permalink)
mtnfreak Contributing Member Join Date: Nov 2002 Location: People's Republic of Boulder Posts: 830	Check your owner's manual. Toyota does replace some of them for free at 80K miles. I'm sure someone here can detail the procedure for checking to see if your's is bad or not. It's real simple on the '89s. $120 sounds about right for the NAPA part, but I've heard of many people switching back to the OEM sensor for a variety of reasons. 17mpg is about right for a 2-ton vehicle with the 3.0. You might see some improvement with a new sensor, but don't expect to be breaking into the 20's. __________________ 89 4Runner, V6, Auto, Some stuff's stock, some's not.

08-06-2003, 09:23 PM	#3 (permalink)
Bumpin' Yota Registered User Join Date: Feb 2003 Location: Sarasota, FL Posts: 3,639	I just swapped out mine. Already have seen a slight improvement in milage but a noticable loss of power as the engine was running rich before. Im going to wait 2-3 tanks before I come to any conclusions though. A mechanic told me that the ECU would fully reset to the new O2 sensor after about 60 keystarts.....thoughts? My freak-of-nature-3.0 just broke into 20-21mpg on this last trip home. Got 165 miles on 1/2 tank doing 70mph, I'll know exact numbers when I fill up again. (no racks, no big tires, 4.11 gear, 50psi, no gunning, no hills, the FL norm...) Hope for 20, but as the previous poster stated, don't expect it. Most 3.0s seem to be lucky to get 17.... __________________ 3vze, 4x4, sr5, 90, auto, LSD 2x dB Drag World Finalist 2003 Nopi Nat. Street B champ 2004 SBN Street C champ 2004 SBN Advncd NW Champ 2004 Former WR Holder in NW. SPL: 159.8db @ 42hz In loving memory of Jamie Riggs 5/15/85 - 10/8/04

08-07-2003, 06:57 AM	#4 (permalink)
russellcframe Registered User Join Date: Jul 2003 Location: Wisconsin Posts: 46	So what is the point of changing it? Forgive my ignorance, but if the fuel economy might only be mildly affected (Not enough to warrant $120 and time to install)....what is the point in changing it at all? I know it's a periodic maitenance item....I just don't understand why (unlike fluids and lubricants that wear down and can decrease component life if not changed regularly). Thanks, Russ

08-07-2003, 07:11 AM	#5 (permalink)
TOR Registered User Join Date: Apr 2003 Location: Plano, TX Posts: 490	Parts O2 sensor, shipped to your front door for $89.26. Some parts you might be able to get away with subbing out at after market stores but I wouldn't do it with 02 sensors. Actually I don't recommend it at all but thats just from what I see everyday from those that do. If you are interested let me know. Todd __________________ 97 4-Runner Limited, 1st Gen Supercharger, TRD air filter, Flo~Pro, 18" BBS wheels, 2.0 pulley, and nitrous express on the way! I am a Toyota Parts Sales rep, if anyone needs Toyota or TRD parts email me or call me! Todd Packer Toyota of Richardson Parts Department 972-238-4465 800-527-2781 todd_packer@toyotaofrichardson.com

08-07-2003, 07:13 AM	#6 (permalink)
russellcframe Registered User Join Date: Jul 2003 Location: Wisconsin Posts: 46	Thanks Todd Sounds like a pretty good price. Can you answer my question about "why" someone should change it in the first place?

08-07-2003, 07:17 AM	#7 (permalink)
mtnfreak Contributing Member Join Date: Nov 2002 Location: People's Republic of Boulder Posts: 830	O2 sensors don't really 'wear out', but they do corrode - the exhaust stream is a nasty place to be. Some of the material in the sensor may even be sacrificial(sp?). Still hoping someone can post the test procedures for your '95. __________________ 89 4Runner, V6, Auto, Some stuff's stock, some's not.

08-07-2003, 07:19 AM	#8 (permalink)
russellcframe Registered User Join Date: Jul 2003 Location: Wisconsin Posts: 46	Yeah a test procedure would be great. I don't mind replacing something if it's needed and beneficial, just don't want to do it for no good reason Thanks again, Russ

08-08-2003, 10:29 AM	#11 (permalink)
mycotopian Registered User Join Date: Jul 2003 Location: Aliso Viejo, California Posts: 156	Can you just clean the o2 sensor and see any improvements?? __________________ 1999 4runner 3.4 4X2 150,000 miles ISR Mod Tundra/OME Lift Addco sways on the way! (damm backorders)

08-09-2003, 08:00 AM	#13 (permalink)
TOR Registered User Join Date: Apr 2003 Location: Plano, TX Posts: 490	02 sensor Yeah cleaning it will do no good just get ya a new one. Todd __________________ 97 4-Runner Limited, 1st Gen Supercharger, TRD air filter, Flo~Pro, 18" BBS wheels, 2.0 pulley, and nitrous express on the way! I am a Toyota Parts Sales rep, if anyone needs Toyota or TRD parts email me or call me! Todd Packer Toyota of Richardson Parts Department 972-238-4465 800-527-2781 todd_packer@toyotaofrichardson.com

08-09-2003, 09:57 AM	#14 (permalink)
KevyWevy Registered User Join Date: Jun 2003 Location: Kirkland, WA Posts: 1,962	yeah so how do you know if its bad? other than having the check engine light on? i just bought my 4Runner about 4 months ago and don't have any maintanace records. __________________ 1994 White 4Runner 5 Speed SR5 4X4 ~121,000 Miles Land Cruiser Coils ~ 1.5" Ball Joint Spacers ~ Buschwaker Fender Flares ~ Cobra 19 DX II ~ Asin Manual Locking Hubs ~ Alpine MP3 HU ~ 2 10" MTX Subs ~ Pioneer 4" Speakers ~ Husky Floor Liners ~ Indiglow Gauges ~ Clear Corners ~ 15"x8" Rock Crawler Wheels ~ 33x12.5 BFG AT's ~ Diff Breathers ~ Yakima Crossbars ~ Sylvania Silver Stars http://community.webshots.com/user/kevywevy84

08-09-2003, 05:05 PM	#18 (permalink)
KevyWevy Registered User Join Date: Jun 2003 Location: Kirkland, WA Posts: 1,962	what is a DMM and where do i get it? im just trying to help out my gas milage a little. __________________ 1994 White 4Runner 5 Speed SR5 4X4 ~121,000 Miles Land Cruiser Coils ~ 1.5" Ball Joint Spacers ~ Buschwaker Fender Flares ~ Cobra 19 DX II ~ Asin Manual Locking Hubs ~ Alpine MP3 HU ~ 2 10" MTX Subs ~ Pioneer 4" Speakers ~ Husky Floor Liners ~ Indiglow Gauges ~ Clear Corners ~ 15"x8" Rock Crawler Wheels ~ 33x12.5 BFG AT's ~ Diff Breathers ~ Yakima Crossbars ~ Sylvania Silver Stars http://community.webshots.com/user/kevywevy84

08-09-2003, 05:27 PM	#20 (permalink)
KevyWevy Registered User Join Date: Jun 2003 Location: Kirkland, WA Posts: 1,962	and what i just look in the owners manual and look at how many volts are going throught it or something? __________________ 1994 White 4Runner 5 Speed SR5 4X4 ~121,000 Miles Land Cruiser Coils ~ 1.5" Ball Joint Spacers ~ Buschwaker Fender Flares ~ Cobra 19 DX II ~ Asin Manual Locking Hubs ~ Alpine MP3 HU ~ 2 10" MTX Subs ~ Pioneer 4" Speakers ~ Husky Floor Liners ~ Indiglow Gauges ~ Clear Corners ~ 15"x8" Rock Crawler Wheels ~ 33x12.5 BFG AT's ~ Diff Breathers ~ Yakima Crossbars ~ Sylvania Silver Stars http://community.webshots.com/user/kevywevy84

08-12-2003, 04:22 AM	#22 (permalink)
Bumpin' Yota Registered User Join Date: Feb 2003 Location: Sarasota, FL Posts: 3,639	Back up to 21.8 mpg........ __________________ 3vze, 4x4, sr5, 90, auto, LSD 2x dB Drag World Finalist 2003 Nopi Nat. Street B champ 2004 SBN Street C champ 2004 SBN Advncd NW Champ 2004 Former WR Holder in NW. SPL: 159.8db @ 42hz In loving memory of Jamie Riggs 5/15/85 - 10/8/04

08-12-2003, 02:45 PM	#23 (permalink)
russellcframe Registered User Join Date: Jul 2003 Location: Wisconsin Posts: 46	Hey Bumpin Yota... About that 21.8...I take it your mpg went up a lot with an O2 sensor replacement. What were you getting before and did you change anything else for that improvement or do you think it was all about the sensor? Thanks.

09-30-2003, 08:08 PM	#25 (permalink)
4x4Fink Super Moderator Staff Join Date: Jul 2003 Location: Centerton, AR Posts: 5,952	Don't mean to bring this post back from the dead but...I am having serious mileage problems. I am getting ~10.8-11.2 MPG city...thats with my lead foot and ECT part of the time. I am thinking it is either a bad 02 sensor, bad AFM (Air Flow Meter, thanks to robinhood) or a clogged cat. There is a pretty bad smell that comes after I rev the engine a little. The smell isn't constant though, usually only after running the engine for a little bit. It is acting like the 02 sensor is about to go bad...I am thinking I should take it to the shop and have them check everything out. What do you all think? Any of you that know me and my lack of skills should know that I am probably not capable of doing any of the diagnosing myself... Comments/Questions? Thanks, Fink __________________ 1985 4Runner 22RE 4WD "Ratchet" 2007 Tacoma Double Cab SB 4x4 V6 TRD Sport AR-TTORA "My work number is 9-1-1."

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