Oil Pressure Logging Stock ECU Pin 64 / MUT83
#1
Oil Pressure Logging Stock ECU Pin 64 / MUT83
Hi All,
After some tinkering last year I reflashed my ECU to read an AEM wideband through the stock rear O2 sensor pin in the ECU, and read the JDM 3 bar MAP. This year I am adding in an AEM Oil Pressure gauge also and would like to log this through the stock ECU as well. From what I am reading on the evoscan website (http://www.evoscan.com/manuals/Evo%2...U%20pinout.pdf), pin 64 on the stock ECU is not used, but is a 0-5V ADC input. There is no physical wire coming into it, but it would not be too hard to add a pin into the connector (http://www.digikey.com/product-detai...319-ND/2044230) . My thought here is simply add the 0-5V wire from the gauge to pin 64 on the ECU, tell evoscan to read MUT83 as the oil pressure, and scale the 0-255 by 150(PSI)/255 and I should have a loggable oil pressure signal through the stock ECU.
I looked around on here and couldn't find any info on anyone using pin 64. Has this been done or does anyone see an issue with this approach? Seems like a pretty simple way to add logging capability to the stock ECU.
Edit 1: So I should have done my HW a little better. The ECU pins I mention in the above link are WRONG for this. Those are the large pins, and pin 64 is one of the small pins. See this post to find the correct one:
https://www.evolutionm.net/forums/ec...ess-how-s.html
Trying to find somewhere to order the small pins from now...
After some tinkering last year I reflashed my ECU to read an AEM wideband through the stock rear O2 sensor pin in the ECU, and read the JDM 3 bar MAP. This year I am adding in an AEM Oil Pressure gauge also and would like to log this through the stock ECU as well. From what I am reading on the evoscan website (http://www.evoscan.com/manuals/Evo%2...U%20pinout.pdf), pin 64 on the stock ECU is not used, but is a 0-5V ADC input. There is no physical wire coming into it, but it would not be too hard to add a pin into the connector (http://www.digikey.com/product-detai...319-ND/2044230) . My thought here is simply add the 0-5V wire from the gauge to pin 64 on the ECU, tell evoscan to read MUT83 as the oil pressure, and scale the 0-255 by 150(PSI)/255 and I should have a loggable oil pressure signal through the stock ECU.
I looked around on here and couldn't find any info on anyone using pin 64. Has this been done or does anyone see an issue with this approach? Seems like a pretty simple way to add logging capability to the stock ECU.
Edit 1: So I should have done my HW a little better. The ECU pins I mention in the above link are WRONG for this. Those are the large pins, and pin 64 is one of the small pins. See this post to find the correct one:
https://www.evolutionm.net/forums/ec...ess-how-s.html
Trying to find somewhere to order the small pins from now...
Last edited by blockade35; Feb 25, 2015 at 06:48 PM.
#2
Evolved Member
iTrader: (1)
Hi All,
After some tinkering last year I reflashed my ECU to read an AEM wideband through the stock rear O2 sensor pin in the ECU, and read the JDM 3 bar MAP. This year I am adding in an AEM Oil Pressure gauge also and would like to log this through the stock ECU as well. From what I am reading on the evoscan website (http://www.evoscan.com/manuals/Evo%2...U%20pinout.pdf), pin 64 on the stock ECU is not used, but is a 0-5V ADC input. There is no physical wire coming into it, but it would not be too hard to add a pin into the connector (http://www.digikey.com/product-detai...319-ND/2044230) . My thought here is simply add the 0-5V wire from the gauge to pin 64 on the ECU, tell evoscan to read MUT83 as the oil pressure, and scale the 0-255 by 150(PSI)/255 and I should have a loggable oil pressure signal through the stock ECU.
I looked around on here and couldn't find any info on anyone using pin 64. Has this been done or does anyone see an issue with this approach? Seems like a pretty simple way to add logging capability to the stock ECU.
After some tinkering last year I reflashed my ECU to read an AEM wideband through the stock rear O2 sensor pin in the ECU, and read the JDM 3 bar MAP. This year I am adding in an AEM Oil Pressure gauge also and would like to log this through the stock ECU as well. From what I am reading on the evoscan website (http://www.evoscan.com/manuals/Evo%2...U%20pinout.pdf), pin 64 on the stock ECU is not used, but is a 0-5V ADC input. There is no physical wire coming into it, but it would not be too hard to add a pin into the connector (http://www.digikey.com/product-detai...319-ND/2044230) . My thought here is simply add the 0-5V wire from the gauge to pin 64 on the ECU, tell evoscan to read MUT83 as the oil pressure, and scale the 0-255 by 150(PSI)/255 and I should have a loggable oil pressure signal through the stock ECU.
I looked around on here and couldn't find any info on anyone using pin 64. Has this been done or does anyone see an issue with this approach? Seems like a pretty simple way to add logging capability to the stock ECU.
#7
This post is the motivation I needed to sort mine.
I installed the sensor/ECU pins years ago and added the Evoscan formulae but never got around to finishing the wiring off
FWIW, I also installed a couple of toggle switches on the back of the glovebox so I could try and utilise a couple of inputs per ADC:
Pin 64: EGT/Oil Temp
Pin 73: LC1
Pin 93: Oil Pressure/Ex Backpressure
It has been so long that I now need to go and read my notes as I can't even remember where I got to with it all
I installed the sensor/ECU pins years ago and added the Evoscan formulae but never got around to finishing the wiring off
FWIW, I also installed a couple of toggle switches on the back of the glovebox so I could try and utilise a couple of inputs per ADC:
Pin 64: EGT/Oil Temp
Pin 73: LC1
Pin 93: Oil Pressure/Ex Backpressure
It has been so long that I now need to go and read my notes as I can't even remember where I got to with it all
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#8
This post is the motivation I needed to sort mine.
I installed the sensor/ECU pins years ago and added the Evoscan formulae but never got around to finishing the wiring off
FWIW, I also installed a couple of toggle switches on the back of the glovebox so I could try and utilise a couple of inputs per ADC:
Pin 64: EGT/Oil Temp
Pin 73: LC1
Pin 93: Oil Pressure/Ex Backpressure
It has been so long that I now need to go and read my notes as I can't even remember where I got to with it all
I installed the sensor/ECU pins years ago and added the Evoscan formulae but never got around to finishing the wiring off
FWIW, I also installed a couple of toggle switches on the back of the glovebox so I could try and utilise a couple of inputs per ADC:
Pin 64: EGT/Oil Temp
Pin 73: LC1
Pin 93: Oil Pressure/Ex Backpressure
It has been so long that I now need to go and read my notes as I can't even remember where I got to with it all
#9
Ok so been quiet for a while here, but the car is finally back together and I got a chance to update the tune today and see how this was working.
The good news is it seems to be logging just fine, which will be great to have for race day. The bad news is that the scaling is off by I want to say around 50%, so I have some work to do there still to figure out why. I am hoping that is the easy part though.
Once I have it all done and dialed in I'll put a full writeup on this mod here and on the upshiftracing.com website.
The good news is it seems to be logging just fine, which will be great to have for race day. The bad news is that the scaling is off by I want to say around 50%, so I have some work to do there still to figure out why. I am hoping that is the easy part though.
Once I have it all done and dialed in I'll put a full writeup on this mod here and on the upshiftracing.com website.
#10
Better late than never, but I got this working properly. I found the transfer function for the AEM sensor on their website and scaled off of that rather than the 0-5v as listed in the instructions. The gauge basically goes from 0.5V to 4.5V max, so you have to adjust the transfer function in Evoscan to match.
For the 100PSI gauge, the function you want is .490*x-12.5 (tested verified in my car).
If you have the 150PSI gauge I believe the function you want it .735*x-18.75.
Short summary of the math here. since the gauge maxes out at 4.5V, 4.5V must equal the max pressure, so for the 100PSI gauge 4.5V = 100PSI. 4.5V on a 0 to 255 scale is 229.5. The gauge also starts 0.5V, so 0.5V = 0 PSI. This creates an offset function. 0.5V on the 0 to 255 scale is 25.5.
So your function must work such that when you input 229.5, you get 100PSI (or 150 is you are on that gauge), and when you input 25.5 you get 0. It's all linear in between, and the math is pretty easy from here.
For the 100PSI gauge, the function you want is .490*x-12.5 (tested verified in my car).
If you have the 150PSI gauge I believe the function you want it .735*x-18.75.
Short summary of the math here. since the gauge maxes out at 4.5V, 4.5V must equal the max pressure, so for the 100PSI gauge 4.5V = 100PSI. 4.5V on a 0 to 255 scale is 229.5. The gauge also starts 0.5V, so 0.5V = 0 PSI. This creates an offset function. 0.5V on the 0 to 255 scale is 25.5.
So your function must work such that when you input 229.5, you get 100PSI (or 150 is you are on that gauge), and when you input 25.5 you get 0. It's all linear in between, and the math is pretty easy from here.
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