The title is labeled as such since I have a GS300 and not an IS300. But anyways, most of the VVTi ecu's work much the same anyways.
Please DO NOT attempt this if you are not an advanced level DIY'er. I will take ZERO responsibility if you kill your EMS or your motor. With that said...on with the guide.
First off open the box. That's the easy part. Second part is to separate the daughterboard from the mainboard. If you cannot do this with confidence then stop right here. If you pull waaay too hard, you have a good possibility of snapping the board in half.
![]()
First off a picture of the AEM EMS main board. This is what you pay $1300 for from AEM lol.
![]()
Picture of the daughterboard for a AEM EMS 1313 box for Mitsubishi EVO8
![]()
These are the resistors you have to disconnect. I just desoldered one side only. Just in case I ever want to put the box back to stock...I still have the original resistor in place.
![]()
Use heat shrink tubing to enclose the resistors and prevent them from shorting adjacent circuits.
![]()
Some of my "interesting" testing methods lol. I wish I had some lab equiptment but unfortunately I'm not that ballin.
![]()
This was in the trial and error stage. I tried different resistors to offset the reading. I initially put a extension wire with a 2 pin socket so I could try different resistors. Buuuuut I ran out of different resistor combinations.
![]()
Ooooooo....what do we have here? A potentiometer!
Perfect solution since I couldn't find that many bare resistors laying around heh. Unfortunately after all that testing, I found out it was all for nothing. Since I don't even need to add in a new resistor at all!
---------------------------------------------------------------
Anyways, at the end of all my testing I found out this. Just pull those 3 resistors. It doesn't need any resistor in there at all to get a correct sensor reading. Here's the reason why and it took me about an hour to figure it out. The daughterboard PCB is actually a 3 layer...initially I thought it was just a plain old 2 layer since the amount of circuitry was very very minimal. The middle layer is a 5V source that a ton of the inputs were tying into!
Before the actual internal mods, I did a ton of testing with my friend and we were both scratching our heads afterwards because all of the sensor input lines were outputting 5V! Seemed a bit strange for a line that was labelled as an input on the AEM pinout diagram. Anyways long story short the stock ECU is outputting a 5V already for the sensors. With the AEM throwing another 5V on top that was throwing off the readings pretty drastically. So just cut the 5V source going to the inputs by disconnecting the resistors I labelled.
Also, keep in mind this is an AEM 1313 box where the crank and cam triggers are picked up with a logic setup...since that's how the EVO8 is setup. I think on a Honda box where the car just uses regular mag pickups without anything extra...you should be able to use the crank and cam inputs without modding anything. However, you will still have to modify inside the box for the coolant temp and air intake temp sensors.
On my setup, I don't plan to use the stock air temp sensor because I have my MAF located right after the turbo. I'm just going to install a GM AIT into the piping right before the throttle body. So that's why I only modded one of the sensor inputs(coolant) rather than doing both for coolant and air. I had to map out the stock sensor voltage vs temp values with a logger and OBD2 scanner hooked up to the car. I got the temp/volt table nailed down solid and its within 1F across the board.
So internally, to get the AEM working for the 1313 box you just pull the resistors out for the crank and cam 5V reference...it's the R1 and R3 resistors that are next to each other. The R15 resistor off to the side by itself is the one for the coolant sensor. Every AEM box will be different so you just have to trace the leads back to the resistor from the pin on the outside of the box.
This is just the internal mods. Easy stuff. If I have time, I'll update this post with the wiring necessary on the PNP harness and some software settings to get the AEM to pick up the 36-2 crank trigger.
For the advanced DIY'ers hope this helps out.
For the beginners, please don't even
Please DO NOT attempt this if you are not an advanced level DIY'er. I will take ZERO responsibility if you kill your EMS or your motor. With that said...on with the guide.
First off open the box. That's the easy part. Second part is to separate the daughterboard from the mainboard. If you cannot do this with confidence then stop right here. If you pull waaay too hard, you have a good possibility of snapping the board in half.
First off a picture of the AEM EMS main board. This is what you pay $1300 for from AEM lol.
Picture of the daughterboard for a AEM EMS 1313 box for Mitsubishi EVO8
These are the resistors you have to disconnect. I just desoldered one side only. Just in case I ever want to put the box back to stock...I still have the original resistor in place.
Use heat shrink tubing to enclose the resistors and prevent them from shorting adjacent circuits.
Some of my "interesting" testing methods lol. I wish I had some lab equiptment but unfortunately I'm not that ballin.
This was in the trial and error stage. I tried different resistors to offset the reading. I initially put a extension wire with a 2 pin socket so I could try different resistors. Buuuuut I ran out of different resistor combinations.
Ooooooo....what do we have here? A potentiometer!
Perfect solution since I couldn't find that many bare resistors laying around heh. Unfortunately after all that testing, I found out it was all for nothing. Since I don't even need to add in a new resistor at all!---------------------------------------------------------------
Anyways, at the end of all my testing I found out this. Just pull those 3 resistors. It doesn't need any resistor in there at all to get a correct sensor reading. Here's the reason why and it took me about an hour to figure it out. The daughterboard PCB is actually a 3 layer...initially I thought it was just a plain old 2 layer since the amount of circuitry was very very minimal. The middle layer is a 5V source that a ton of the inputs were tying into!
Before the actual internal mods, I did a ton of testing with my friend and we were both scratching our heads afterwards because all of the sensor input lines were outputting 5V! Seemed a bit strange for a line that was labelled as an input on the AEM pinout diagram. Anyways long story short the stock ECU is outputting a 5V already for the sensors. With the AEM throwing another 5V on top that was throwing off the readings pretty drastically. So just cut the 5V source going to the inputs by disconnecting the resistors I labelled.
Also, keep in mind this is an AEM 1313 box where the crank and cam triggers are picked up with a logic setup...since that's how the EVO8 is setup. I think on a Honda box where the car just uses regular mag pickups without anything extra...you should be able to use the crank and cam inputs without modding anything. However, you will still have to modify inside the box for the coolant temp and air intake temp sensors.
On my setup, I don't plan to use the stock air temp sensor because I have my MAF located right after the turbo. I'm just going to install a GM AIT into the piping right before the throttle body. So that's why I only modded one of the sensor inputs(coolant) rather than doing both for coolant and air. I had to map out the stock sensor voltage vs temp values with a logger and OBD2 scanner hooked up to the car. I got the temp/volt table nailed down solid and its within 1F across the board.
So internally, to get the AEM working for the 1313 box you just pull the resistors out for the crank and cam 5V reference...it's the R1 and R3 resistors that are next to each other. The R15 resistor off to the side by itself is the one for the coolant sensor. Every AEM box will be different so you just have to trace the leads back to the resistor from the pin on the outside of the box.
This is just the internal mods. Easy stuff. If I have time, I'll update this post with the wiring necessary on the PNP harness and some software settings to get the AEM to pick up the 36-2 crank trigger.
For the advanced DIY'ers hope this helps out.
For the beginners, please don't even
