top Posted September 13, 2008 Share Posted September 13, 2008 I know there's a lot of posts regarding o2 sensors. I've searched through them but haven't found much information about "before and after" figures for mpg and performance. My car's done about 120k miles and I'm assuming they've never been changed. If it only makes 1 or 2 mpg difference I'm not going to bother but if the difference is considerable I'm going to go for it. (I think I'd go for new ones rather than trying the lemon trick.) My car is a '94 n/a and does about 220 miles to a tank round town or about 310 on motorway runs at about 80mph. The acceleration is ok but could be better and I'm sure it was faster when I first bought it 3 yrs ago! What difference to mpg and performance have people noticed after changing their o2 sensors? Thanks guys. Quote Link to comment Share on other sites More sharing options...
imi Posted September 13, 2008 Share Posted September 13, 2008 if anything made it slightly worse - LOL Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 13, 2008 Share Posted September 13, 2008 I'd be interested in this also. Obviously everyone's car is going to be a bit different. Sounds like you get low 20s mpg, which sounds about right. I doubt whether new O2 sensors would make much difference, but I'm willing to be corrected.... Quote Link to comment Share on other sites More sharing options...
AndyT Posted September 13, 2008 Share Posted September 13, 2008 I'd be interested in this also. Obviously everyone's car is going to be a bit different. Sounds like you get low 20s mpg, which sounds about right. I doubt whether new O2 sensors would make much difference, but I'm willing to be corrected.... Spot on. Does sound as if you need one right now bud. Low 20's is right. When you get 15 or so. Look at changing. Recommended change is 30000 iirc. So you're doing well. When you do change, get the proper oem. False economy not too. Quote Link to comment Share on other sites More sharing options...
Dazzi Posted September 13, 2008 Share Posted September 13, 2008 Just before I changed my 02 sensors I did 245 miles to a tank (VPower). After I changed them with Continental Direct Universal 02 sensors I managed 370miles to a tank (VPower again). Another thing that amazed me was on the dyno day I attended earlier in the year. The na supras were running 192, 189, 208 and mine 225hp. I have no proof but I think it made a big difference in performance as there was such a huge gap in power. Quote Link to comment Share on other sites More sharing options...
Ewen Posted September 13, 2008 Share Posted September 13, 2008 Haven't noticed a difference here, but I'm low mileage and I reckon the old one was still fine. Feels good to have a new one on the car though...if I had the money I'd replace everything for brand new OEM. Quote Link to comment Share on other sites More sharing options...
Mike M Posted September 14, 2008 Share Posted September 14, 2008 Well I changed mine when the car had done around 95K and it made the idle terrible at first, it was chugging and sitting about 500 revs. Sorted itself out once I'd got home from the garage (about 70 miles). Getting good mileage tho, 415miles to a tank was my record last month. Quote Link to comment Share on other sites More sharing options...
Dan8 Posted September 15, 2008 Share Posted September 15, 2008 what sensor are they is it a Zircona type sensora “Titania” or “Planar” type Sensors Quote Link to comment Share on other sites More sharing options...
Dan8 Posted September 15, 2008 Share Posted September 15, 2008 can you use universals Quote Link to comment Share on other sites More sharing options...
Matt _Aero top_ Posted September 15, 2008 Share Posted September 15, 2008 can you use universals yes you can i got a link to a supplier somewhere that another member on here provided for me but changing mine didn't really make that much difference though the old ones still looked in good condition it was mostly for piece of mind why i swopped them . Quote Link to comment Share on other sites More sharing options...
Matt _Aero top_ Posted September 15, 2008 Share Posted September 15, 2008 Well I changed mine when the car had done around 95K and it made the idle terrible at first, it was chugging and sitting about 500 revs. Sorted itself out once I'd got home from the garage (about 70 miles). Getting good mileage tho, 415miles to a tank was my record last month. take it that mileage was on a run somewhere Quote Link to comment Share on other sites More sharing options...
Mike M Posted September 15, 2008 Share Posted September 15, 2008 take it that mileage was on a run somewhere Nope, just pootling about most of the time as we had rain for days on end and a few blasts mixed in. Worked out the average at 31mpg. Quote Link to comment Share on other sites More sharing options...
mr lover Posted September 15, 2008 Share Posted September 15, 2008 no difference here at all, changed mine at 48k (miles) Quote Link to comment Share on other sites More sharing options...
cwtt Posted September 15, 2008 Share Posted September 15, 2008 Remember, only the primary (the one closest to the motor) is used by the ecu for gas mileage. The rear o2 is used for emissions. So I wouldnt worry about the rear o2 at all. Infact I dont have one Quote Link to comment Share on other sites More sharing options...
monkey3 Posted September 16, 2008 Share Posted September 16, 2008 415 miles!!!!!!!!!!!!!!!! from a TT? Were you rolling? Is there a block of wood under the right hand pedal? My best ever was about 320-340 and most of those were motorway miles in 6 at about 70-80 constantly. I can't see that changing an O2 sensor is going to give me an extra 100 miles on a tank and being able to give it a bit of a blat as well. I can confirm though that mine was having some stalling issues recently, but after soaking the O2 sensor in lemon juice for about 4 days (I forgot to take it out... whoops) the stalling issue has gone away. Quote Link to comment Share on other sites More sharing options...
stevie_b Posted September 16, 2008 Share Posted September 16, 2008 Remember, only the primary (the one closest to the motor) is used by the ecu for gas mileage. The rear o2 is used for emissions. So I wouldnt worry about the rear o2 at all. Infact I dont have one Interesting info. When you say it's "used for emissions", wouldn't it still provide feedback to the engine which could then have a knock-on effect on fuelling? Quote Link to comment Share on other sites More sharing options...
bigbloodyturbo Posted September 16, 2008 Share Posted September 16, 2008 I think the second o2 just confirms the output of the 1st o2, it makes sure that the first one is operating correctly, and that the cat is in good condition, i would imagine if the second one detected a problem with the first one or atleast gave the impression that it did, then the ecu might do something to the fuelling but i dont think there's much it could do anyway becasue if it richens it up then thats just going to damage the cat even more, and its never going to lean it out on purpose. All it will do probably is turn a light on in the dash so toyota can relieve you of some more money to turn it off. Quote Link to comment Share on other sites More sharing options...
Mike M Posted September 16, 2008 Share Posted September 16, 2008 Mind that Jspecs only have one O2 sensor unless its an NA. Quote Link to comment Share on other sites More sharing options...
TrickTT Posted September 16, 2008 Share Posted September 16, 2008 Just before I changed my 02 sensors I did 245 miles to a tank (VPower). After I changed them with Continental Direct Universal 02 sensors I managed 370miles to a tank (VPower again). Another thing that amazed me was on the dyno day I attended earlier in the year. The na supras were running 192, 189, 208 and mine 225hp. I have no proof but I think it made a big difference in performance as there was such a huge gap in power. Wont make any difference on a dyno run, the output from the O2 sensor is only used for closed loop, low speed running and not used for WOT runs. Quote Link to comment Share on other sites More sharing options...
Dazzi Posted September 17, 2008 Share Posted September 17, 2008 Wont make any difference on a dyno run, the output from the O2 sensor is only used for closed loop, low speed running and not used for WOT runs. Well my engine must be in good nick then Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 17, 2008 Share Posted September 17, 2008 what sensor are they is it a Zircona type sensora “Titania” or “Planar” type Sensors Zirconia. Quote Link to comment Share on other sites More sharing options...
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