fordy_alexsupra Posted April 5, 2012 Share Posted April 5, 2012 I have a JDM BPU supra (upgraded fuel pump ect) and I managed to get 130 motor way miles from 30 litres of BP Ultimate (97). So I done a voltage test on my O2 sensor after a 30 mile drive (hot engine) a number of times using this advice, http://www.mkivsupra.net/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=oxygen The voltage is fluctuating up and down every second at idle from 0.05v to 0.85v. I am confused what this means, is my engine is running rich from another source and the O2 sensor is reading this i.e working correctly or could it just mean the O2 needs changing? The O2 sensor is a denso from amazon.com but I have ordered a oem toyota sensor and picking that up Saturday but thought I'd get some opinions first. I have checked the ohms of the Coolant sensor on the neck (2wires) using the supra manual and it is working properly. Quote Link to comment Share on other sites More sharing options...
Thomas.B Posted April 5, 2012 Share Posted April 5, 2012 You get plenty more then I do now... I got 120miles to a full tank! I have since then changed the thermostat, 02 sensor, sparkplugs and all oils. No change! Have just now changed the ECU temp-sensor but havent had the time to drive it yet, if this doesnt do it ill try the BOV also. I have a JDM BPU supra (upgraded fuel pump ect) and I managed to get 130 motor way miles from 30 litres of BP Ultimate (97). So I done a voltage test on my O2 sensor after a 30 mile drive (hot engine) a number of times using this advice, http://www.mkivsupra.net/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=oxygen The voltage is fluctuating up and down every second at idle from 0.05v to 0.85v. I am confused what this means, is my engine is running rich from another source and the O2 sensor is reading this i.e working correctly or could it just mean the O2 needs changing? The O2 sensor is a denso from amazon.com but I have ordered a oem toyota sensor and picking that up Saturday but thought I'd get some opinions first. I have checked the ohms of the Coolant sensor on the neck (2wires) using the supra manual and it is working properly. Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 8, 2012 Author Share Posted April 8, 2012 Bump? Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 11, 2012 Author Share Posted April 11, 2012 Bump Quote Link to comment Share on other sites More sharing options...
matthewm1965 Posted April 11, 2012 Share Posted April 11, 2012 The voltage fluctuating up and down every second indicates that it is working correctly. It's when it stays at one setting or only moves up and down slowly that you have a problem. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted April 11, 2012 Share Posted April 11, 2012 O2 voltage should go from 0.2 to 0.8 minimum, and the deflection period should be around once every 2 seconds, if its outside these limits then there is a problem. Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 11, 2012 Author Share Posted April 11, 2012 It is outside that voltage, 0.05 to 0.85 Thanks Quote Link to comment Share on other sites More sharing options...
Iky Posted April 12, 2012 Share Posted April 12, 2012 Have you managed to fit the new sensor yet fordy? We both seem to have the same problem Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 12, 2012 Author Share Posted April 12, 2012 Have you managed to fit the new sensor yet fordy? We both seem to have the same problem As soon as this rain stops I will Naa tomorrow afternoon it will be done and ill post on here let you know the results! Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 15, 2012 Author Share Posted April 15, 2012 (edited) New toyota oem sensor fitted, went for a drive and tested. It is a similar result, the voltage hangs around the 0.6v-0.7v range for a second and drops down slowly to the low 0.2v and back up again half the speed as before. Seems like it has smoother reading unlike before, where the voltage was jumping up and down very quickly from low to high volts. Edited April 15, 2012 by fordy_alexsupra (see edit history) Quote Link to comment Share on other sites More sharing options...
Iky Posted April 16, 2012 Share Posted April 16, 2012 Cool, have you put some miles on it yet? The voltage isn't going below 1V this time. I left mine soaking in lemon juice for 3 days and i'm just inthe process of checking how many miles it does with a full tank. New toyota oem sensor fitted, went for a drive and tested. It is a similar result, the voltage hangs around the 0.6v-0.7v range for a second and drops down slowly to the low 0.2v and back up again half the speed as before. Seems like it has smoother reading unlike before, where the voltage was jumping up and down very quickly from low to high volts. /QUOTE] Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted April 16, 2012 Share Posted April 16, 2012 New toyota oem sensor fitted, went for a drive and tested. It is a similar result, the voltage hangs around the 0.6v-0.7v range for a second and drops down slowly to the low 0.2v and back up again half the speed as before. Seems like it has smoother reading unlike before, where the voltage was jumping up and down very quickly from low to high volts. /QUOTE] Presumably you're measuring the O2 voltage with a multimeter, and did you say that you're accessing through the diagnosis port in the engine bay? are you sure the meter is capable of responding quick enough to the O2 voltage output, because when hot the voltage will seem stick around 0.45v if the response rate is slow, and you won't see the fluctuations as the ECU hunts around trying to keep the voltage stable by adding and removing injector duty cycle, so you could possibly be on a wild goose chase! Have you done any runs to check fuel consumption? you could also find someone with wide-bandnd and double check, if you know a friendly MOT garage they may shove a probe up your exhaust (ouch) to check O2 for you. Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 17, 2012 Author Share Posted April 17, 2012 Presumably you're measuring the O2 voltage with a multimeter, and did you say that you're accessing through the diagnosis port in the engine bay? are you sure the meter is capable of responding quick enough to the O2 voltage output, because when hot the voltage will seem stick around 0.45v if the response rate is slow, and you won't see the fluctuations as the ECU hunts around trying to keep the voltage stable by adding and removing injector duty cycle, so you could possibly be on a wild goose chase! Have you done any runs to check fuel consumption? you could also find someone with wide-bandnd and double check, if you know a friendly MOT garage they may shove a probe up your exhaust (ouch) to check O2 for you. Yes, Measuring the hot voltage output using the Diagnosis Port OX1 and neg bat. It is a new electronic (digital) multimeter, so it possibly is slow to keep up with the output figures. (http://www.mkivsupra.net/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=oxygen) This guide states 'a hunt between 0.5v and 0.7v' but with the new O2 it hunts (as stated in my previous post) between 0.2v and 0.6-0.7v, quite confused because now has me thinking it is something else (i have tested the ecu coolant temp sensor) or my multimeter!? Although my MPG is better, 30 litres of bp ultimate got me 180miles and that is a 50 mile improvement I did put pedal to the metal a few times Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted April 17, 2012 Share Posted April 17, 2012 If your fuel consumption is now a lot closer to its original, i would not be overly concerned with the O2 voltage, the actual voltage you see will be dependent on how much the ECU is adjusting the fueling in order to maintain stoic at idle, although it should be a definite deflection either side of 0.45 v, as i said you would be able to see the actual AFRs by using a wide-band lambda set up. Quote Link to comment Share on other sites More sharing options...
Iky Posted April 18, 2012 Share Posted April 18, 2012 Yes, Measuring the hot voltage output using the Diagnosis Port OX1 and neg bat. It is a new electronic (digital) multimeter, so it possibly is slow to keep up with the output figures. (http://www.mkivsupra.net/vbb/showthread.php?35940-Narrowband-O2-Sensor&highlight=oxygen) This guide states 'a hunt between 0.5v and 0.7v' but with the new O2 it hunts (as stated in my previous post) between 0.2v and 0.6-0.7v, quite confused because now has me thinking it is something else (i have tested the ecu coolant temp sensor) or my multimeter!? Although my MPG is better, 30 litres of bp ultimate got me 180miles and that is a 50 mile improvement I did put pedal to the metal a few times If my maths is correct, thats actually pretty good MPG (I make it 27.2MPG) So looks like you fuel economy is sorted now. Quote Link to comment Share on other sites More sharing options...
Thomas.B Posted April 19, 2012 Share Posted April 19, 2012 You have around 1.1 liters/km thats HALF of mine and at the same time that is the amount when I drive with an egg under my foot..... I'd say 1.1 is considered good if you count in that you have been flooring it abit. Quote Link to comment Share on other sites More sharing options...
fordy_alexsupra Posted April 19, 2012 Author Share Posted April 19, 2012 30 leters got me 290km so, 1leter/9.6km Quote Link to comment Share on other sites More sharing options...
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