FOSTA Posted February 25, 2013 Share Posted February 25, 2013 Funny one really, dose anybody know why the supra uses 2 lambda/02 sensors and not just 1? Quote Link to comment Share on other sites More sharing options...
Shane Posted February 25, 2013 Share Posted February 25, 2013 Its only the NA that uses 2, the TT uses one. On the NA, one monitors cylinders 12&3, and the other 45&6 I can only assume that having 2 with each one monitoring just 3 cylinders the ecu has greater control. Am sure someone will be along shortly to confirm this assumption or tell us the real reason why. Quote Link to comment Share on other sites More sharing options...
FOSTA Posted February 25, 2013 Author Share Posted February 25, 2013 (edited) Yeah mine is NA-T The reason I ask is from day one of being turbod my A/F gauge on cruising and idle is constantly moving from 14.1-15.4 back and forth! Quite quickly And I've seen another NA-T A/F gauge and is moves from 14.7-14.8 and its quite static! Now with mine I only have 1 02 sensor fitted and I've split the wire to both signal wires going to the ecu so the ecu sees the same reading for both sensors. Now I measured with a muti-meter another na's lambda readings and between both sensors it was only reading 0.04v-0.03v difference between the 2 sensors, so would I be right in thinking the ecu sees both readings and corrects the fueling in the middle on both readings giving a more static reading on a A/F gauge? Cheers Edited February 25, 2013 by FOSTA (see edit history) Quote Link to comment Share on other sites More sharing options...
Shane Posted February 25, 2013 Share Posted February 25, 2013 Ok so you have a wideband sensor fitted? Some have a narrow band output for the existing ECU and then the wideband output is feeding the gauge. But, I have no idea how the stock NA set up actually does the correction using the 2 sensors. The fact they use 2 sensors to me suggests they tweak the afrs to the two halves of the engine seperatley, but thats just me guessing, and when it comes to afrs, you dont want to rely too much on that. Someone like Ryan or IanC would know exactly how it works I would think. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 25, 2013 Share Posted February 25, 2013 I really cant see the ECU doing anything other than averaging the two readings out and adjusting the injector DC/duration to suite, if it does adjust two banks of three injectors separately i cant see just what that would gain, but i guess its possible, and at a guess it could account for the slightly less stable adjustment reading on cruse. If your NA/T then what are youusingg to adjust thefuelingg during boost? Quote Link to comment Share on other sites More sharing options...
Shane Posted February 25, 2013 Share Posted February 25, 2013 I really cant see the ECU doing anything other than averaging the two readings out and adjusting the injector DC/duration to suite, if it does adjust two banks of three injectors separately i cant see just what that would gain, but i guess its possible, and at a guess it could account for the slightly less stable adjustment reading on cruse. If your NA/T then what are youusingg to adjust thefuelingg during boost? That makes sense, other than if that is the case why 2? If they were using the average from both, then a single sensor would do the same thing wouldn't it? Quote Link to comment Share on other sites More sharing options...
FOSTA Posted February 25, 2013 Author Share Posted February 25, 2013 Yeah I have a AEM wideband fitted to feed the gauge and 1 sensor to feed the signal to the 2 ecu wires so the stock ecu sees the same reading from both wires. I'm piggyback running the greddy e-manage ultimate mapped by Ryan. Don't get me wrong the car runs and feels perfect, its just if the A/F ratios are ment to be more stable off boost then I'd like to try and sort that out Thanks guys Quote Link to comment Share on other sites More sharing options...
Fly Posted February 25, 2013 Share Posted February 25, 2013 FOSTA, what shane said. See if your WB O2 has a narrowband simulator output (make sure if it has more than one its the correct voltage output) that may then stabilise your AFR reading. I have been researching the reson for two to not much avail i did read something along the lines of the Toyota ECU running two independant maps and using the two o2 sensors to adjust each map but that seems nuts to me. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 25, 2013 Share Posted February 25, 2013 FOSTA, what shane said. See if your WB O2 has a narrowband simulator output (make sure if it has more than one its the correct voltage output) that may then stabilise your AFR reading. I have been researching the reson for two to not much avail i did read something along the lines of the Toyota ECU running two independant maps and using the two o2 sensors to adjust each map but that seems nuts to me. I will however he must have the correct output otherwise it wouldn't run correctly, the ECU will only respond to a 0.2 to 0.9v narrow-band output anything else and it will not function. Quote Link to comment Share on other sites More sharing options...
Fly Posted February 25, 2013 Share Posted February 25, 2013 Hence why i added this little gem : - "make sure if it has more than one its the correct voltage output" ) Quote Link to comment Share on other sites More sharing options...
FOSTA Posted February 25, 2013 Author Share Posted February 25, 2013 I will however he must have the correct output otherwise it wouldn't run correctly, the ECU will only respond to a 0.2 to 0.9v narrow-band output anything else and it will not function. Yeah we'll that might explain why a when I first converted to NA-T, I just bought 2 universal bosch single wire sensors and it ran like a bag of s@£t. So I unplugged them and it ran spot on, then I read on the is forum you can run 1 sensor and connect the 2 wires to the one sensor so that's what I done and its ran spot on ever since ( using stock denso sensor of corse) Just with seeing another NA-t with a more static reading I wanted mine to be the same if that's how it's ment to be. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 25, 2013 Share Posted February 25, 2013 Its going to vary fella, and add to that you may have the EMU setup to fool the std ECU into thinking its open loop, that could well cause the slightly more unstable idle AFRs, if its any consolation my big single idle with an EMU was the same, and thats just made me remember why, if you have bigger injectors, the EMU is not great at injector lag times, and that could cause this. Quote Link to comment Share on other sites More sharing options...
Fly Posted February 25, 2013 Share Posted February 25, 2013 I will however he must have the correct output otherwise it wouldn't run correctly, the ECU will only respond to a 0.2 to 0.9v narrow-band output anything else and it will not function. Just as you mentioned this would you program 0.2 volts to be 15 afr and 0.9 volts to be 14 afr? My stock factory settings for the wb are set to 1.1 volts for 14 afr and 0.1 v as 15 afr but I can change the output voltages Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 25, 2013 Share Posted February 25, 2013 Just as you mentioned this would you program 0.2 volts to be 15 afr and 0.9 volts to be 14 afr? My stock factory settings for the wb are set to 1.1 volts for 14 afr and 0.1 v as 15 afr but I can change the output voltages Just answered your PM, and now i have seen this i see what you mean about changing the lambda value, as i said the figure the ECU is looking for is 0.45v this is the trigger point (with some leeway) for it to adjust the fueling, 0.45v on a normal lambda sensor equates to 14.7AFR the lower and higher figures are just that the ECU does not know what the AFR is, just that its past the adjustment threshold either way. Quote Link to comment Share on other sites More sharing options...
Fly Posted February 25, 2013 Share Posted February 25, 2013 Thanks for that, this says to me I can set my narrowband voltage output range from .2 -.9 v with an afr value of 15-14 Quote Link to comment Share on other sites More sharing options...
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