Robzki Posted February 2, 2012 Share Posted February 2, 2012 (edited) Hi all Bpu TT Jdm Auto I have been reliably informed that the supra has pretty much doubled its insatiable need for fuel in the last two weeks. A tank full used to last almost 2 weeks. She filled it up last Wednesday and had to put in £76 to fill it again today. I know that the brakes aren't binding as I checked those last week as I have had problems with seized brakes so check this regularly. Also no fuel leaks. The Afr's are pretty consistent at 14.5-14.8. Am I right in assuming that if there was a problem with the 02 sensors and it was running rich I wouldn't get such a stable reading and would be reading lower? IF I had a misfire would the completely unburned fuel affect the reading on the AFR. Any ideas on what to check, as it is it has done roughly 6 trips of 30miles, so 180 miles on roughly 12 gallons, So 15mpg ish. She is a steady driver and wouldn't have thrashed it as its not her style and it has been seriously icy on the roads she drives and knows better than to risk any stupid driving. Cheers Rob Edited February 2, 2012 by Robzki (see edit history) Quote Link to comment Share on other sites More sharing options...
fastcar Posted February 2, 2012 Share Posted February 2, 2012 how old is your O2 sensor when did you last change the spark plugs Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 2, 2012 Author Share Posted February 2, 2012 I would guess that the o2 sensor has never been changed, The plugs were changed to iridium 12mths/15k miles ago. I was thinking o2 sensor but thought it strange that the afr's are spot on Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 2, 2012 Share Posted February 2, 2012 If the AFRs are consistent during closed loop, and idle, and go rich under load, then the std sensor should be OK, misfires will normally show up as rich AFRs. I would also change the plugs, after 15K on a turbo car despite the long life rep, and see if there is any change. Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 2, 2012 Author Share Posted February 2, 2012 Thanks mate, appreciate the help, I'll research what closed loop is I get about 12 at startup then gradually go to 14.4-15 ish when warm. it does fluctuate probably twice a second approx going high then low. it does this on a steady drive as well, it rarely gets a good spanking so couldn't tell you what they are at wot. I'll order some plugs and see how I get on Thanks again R. Quote Link to comment Share on other sites More sharing options...
Havard Posted February 3, 2012 Share Posted February 3, 2012 For the money I would replace both. I did recently and got 350 miles out of my last tank on the trip to the LMM meet. Quote Link to comment Share on other sites More sharing options...
Littler Posted February 3, 2012 Share Posted February 3, 2012 For the money I would replace both. I did recently and got 350 miles out of my last tank on the trip to the LMM meet. Same here, I managed 326 miles out of a tank for LMM with just under a 1/4 left. Wouldn't of been able to do that without changing the O2 sensor. It's worth doing especially if it's never been changed! Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks I have been toying with the idea of changing them for a year or two just for the sake of it, after I fitted the afr gauge I just thought that with the correct reading then the sensors couldn't be at fault? I didn't want to change them as it would be a waste of money if they are working fine. I will fit new sensors and plugs and go from there, I'll go and research where to get the o2 sensors unless anyone has bought any recently for a good price. Quote Link to comment Share on other sites More sharing options...
Nic Posted February 3, 2012 Share Posted February 3, 2012 It explains how to test the O2 sensor here http://www.mkivsupra.net/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=lambda Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks Nic, on the ball as usual Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted February 3, 2012 Share Posted February 3, 2012 I have not brought any from here http://www.rockauto.com/ but saw others from the forum have. Apparently you can get two flange type O2 sensors delivered for about £80 from the USA. Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted February 3, 2012 Share Posted February 3, 2012 I have not brought any from here http://www.rockauto.com/ but saw others from the forum have. Apparently you can get two flange type O2 sensors delivered for about £80 from the USA although I have a NA and I think you only need one for a TT. Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks Graham I've not seen that place looks interesting, never sure on ordering parts from the usa. Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted February 3, 2012 Share Posted February 3, 2012 No me neither but I saw other people have used them with no problems but cannot find the thread, I keep considering changing mine as it would be worthwhile rather than trying to work out my mpg. Quote Link to comment Share on other sites More sharing options...
fastcar Posted February 3, 2012 Share Posted February 3, 2012 I think I got one from mr T last year and it set me back about £140-£150. From Steve Manley Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 hmm, sounds an expensive thing to try, I'll check the voltage on it later when it gets back. Could someone in the know put my mind at ease that the afr's would still read ok even with a faulty o2 sensor? From what I can see it gets to closed loop ok, rises steadily from cold to warm(12-14) then when it gets to 14.6ish it then hunts between 14-15 approx Thanks for all of the advice and help, much appreciated. R. Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted February 3, 2012 Share Posted February 3, 2012 If you check out the how to clean o2 sensors on a NA guide you see their konrad has used rock auto if that is what is putting you off using them. Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks Graham, I'm less put off when I saw what mr T wanted I have seen threads in the past with links to some denso parts a lot cheaper than mr T I think. What is putting me off is replacing something that is working ok and its another issue. Cheers R. I could add a datalogger to my setup for nearly the price of the sensors Quote Link to comment Share on other sites More sharing options...
Graham1984 Posted February 3, 2012 Share Posted February 3, 2012 Yeah MR T wants a lot for them and rock auto sell my NA o2's for £23 each. It's one of the more annoying problems as my mpg seams ok at times and crap at others but I imagine most of that is all down to my driving style I am even being sad enough to see what the mileage is like if I don't let the inlet valve open up at 4.5 rpm. I need a life. Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Quote Link to comment Share on other sites More sharing options...
Littler Posted February 3, 2012 Share Posted February 3, 2012 I have not brought any from here http://www.rockauto.com/ but saw others from the forum have. Apparently you can get two flange type O2 sensors delivered for about £80 from the USA although I have a NA and I think you only need one for a TT. I got mine from there for about £67 delivered for my TT and got it really quickly. I'll try and find the link to the right one for you. And yep you only need one in a TT Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks Quote Link to comment Share on other sites More sharing options...
Littler Posted February 3, 2012 Share Posted February 3, 2012 (edited) This is the page: http://www.rockauto.com/catalog/raframecatalog.php?carcode=1278604&parttype=5132 The one you need for a TT is the one where the 'Denso Part' is '2344514', the part is £37.86 but with delivery, tax and everything works out at £63 ish (just found my invoice lol) And like I say this is fitted to mine and has been for a few months and for the LMM meet I got 326 miles out of a tank with just under a 1/4 left Hope that helps Edited February 3, 2012 by Littler (see edit history) Quote Link to comment Share on other sites More sharing options...
Robzki Posted February 3, 2012 Author Share Posted February 3, 2012 really does thanks mate, much appreciated Quote Link to comment Share on other sites More sharing options...
fastcar Posted February 3, 2012 Share Posted February 3, 2012 seams like a good price will have to remember this for next time:thumbs: Quote Link to comment Share on other sites More sharing options...
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