kaahari Posted January 31, 2011 Share Posted January 31, 2011 Hi! Anyone knows place to get resistance values for 2jz temp / etc sensors? I`ve only found US site repair manual with limit values (short and open circuits) Would be useful to test: Coolant temp sensor MAP Intake temp sensor Lower coolant (bottom of rad) ? Oil temp sensor What those last two are connected on jdm 2jz? Do they effect on stock ecu at all? Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted January 31, 2011 Share Posted January 31, 2011 You're in luck today! I spent some time about a month ago characterising the above sensors. With the help of a freezer and an oven I took 3 resistance measurements then applied a bit of Steinhart-Hart magic to get the following data. Be aware that this is based on a sample size of 1 with brand new sensors so you are likely to see some variance from my results. No code has to be inserted here. For the stock MAP sensor, I've empirically found the output voltage to have the following relationship: Output Voltage (Volts) = (Absolute Manifold Pressure (kpa) * 0.018358025) + 0.744135802 At 100 kpa (atmospheric) you should see about 2.6V. The sensor in the bottom of the radiator is actually a switch. From the service manual, it should open at 97 degrees C and close at 88 degrees C. The switch is only used to control the small electric fan next to the viscous fan. I'm not aware of any stock oil temperature sensor. Quote Link to comment Share on other sites More sharing options...
Ian C Posted February 1, 2011 Share Posted February 1, 2011 Blimey that's good work Thanks for sharing that! I collated the pressure vs voltage data from loads of datalogs to get a table of pressure vs voltage off the stock Map sensor, and found that atmospheric is 2.65v so I'm glad that tallies with what you got I've uploaded the spreadsheet somewhere around here before, I don't have it to hand at the moment. -Ian Quote Link to comment Share on other sites More sharing options...
kaahari Posted February 1, 2011 Author Share Posted February 1, 2011 (edited) You're in luck today! I spent some time about a month ago characterising the above sensors. thanks, just what i needed and very helpful to diagnose those broblems! Do you mind if i share this info to local finnish club, with proper © markings of course or is this sticky here somewhere? Edited February 1, 2011 by kaahari (see edit history) Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted February 1, 2011 Share Posted February 1, 2011 Do you mind if i share this info to local finnish club I don't mind at all. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 1, 2011 Share Posted February 1, 2011 So basically the water temp and intake air temp sensors are electrically very similar? Excellent work and very commendable to share it Andy, thank you. Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted February 1, 2011 Share Posted February 1, 2011 So basically the water temp and intake air temp sensors are electrically very similar? Pretty much, it's only at low temperatures where the resistances are divergent. When making the measurements, I made sure to get all the sensors were at the same temperature by physically locating them together and letting them dwell for nearly an hour and a half while watching the resistance change against time so I'm fairly confident with the results. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 1, 2011 Share Posted February 1, 2011 Thanks Andy. Very useful and hard won results. I wonder if this could and should be a "stickie" Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 12, 2011 Share Posted March 12, 2011 Found my spreadsheet It's a stock MAP sensors pressure-to-voltage table. -IanStock MAP V vs Pr.xls Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 12, 2011 Share Posted March 12, 2011 Poached for Tech Reference section Quote Link to comment Share on other sites More sharing options...
Calorus Posted January 12, 2015 Share Posted January 12, 2015 Andy, this is a gem of a bit of work, thanks for this (+ a bump to make it easier to find) Quote Link to comment Share on other sites More sharing options...
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