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Discussion Starter #1
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!

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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 :p
 

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good stuff! I'm glad to see IS owners starting to seriously share information like this, rather than keeping it all secret. Maybe one day I'll get around to doing a stand alone on my V8... I just like having the ability to pass emissions with a simple OBD II scan. :)

-B
 

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Whats the difference between the AEM 1313 box and the AEM 1020 for the honda? Do you have to mod both to make them work on the is300?
+rep for your pioneering... I wish I had the funds to this stuff :(!
 

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BIG REP 2 a DIYer explaining and showing us!!!
 

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Cool man. That was very nice of you to take your time to explain it. You are going to be running the 1313? Why instead of the 1050?
 

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Discussion Starter #9
Cool man. That was very nice of you to take your time to explain it. You are going to be running the 1313? Why instead of the 1050?
All AEM boxes are pretty much the same. They just have different pinouts and connectors. I used the 1313 EVO8 box because I found a cheap deal on it and it came with AEM 3.5bar & intake air temp sensors. I paid about $700 for it used on ebay lol. You can technically use anything you want...Toyota box, Honda box, Ford, Mitsu, Dodge, etc. It's all the same thing just different pinouts. And since you have to DIY and custom build a harness anyway, it really doesn't matter what box you use. Just find the cheapest box possible. Some people use Honda boxes since the ECU connectors are easier to find and generally cheaper. If you pop open the boxes and examine the main control board, I bet you that they are all pretty much identical. Procedure is the same if you get a Honda box or whatever. You gotta go in and remove those same resistors. Just trace them back and check for continuity from the pin at the connector outside the box.
 

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All AEM boxes are pretty much the same. They just have different pinouts and connectors. I used the 1313 EVO8 box because I found a cheap deal on it and it came with AEM 3.5bar & intake air temp sensors. I paid about $700 for it used on ebay lol. You can technically use anything you want...Toyota box, Honda box, Ford, Mitsu, Dodge, etc. It's all the same thing just different pinouts. And since you have to DIY and custom build a harness anyway, it really doesn't matter what box you use. Just find the cheapest box possible. Some people use Honda boxes since the ECU connectors are easier to find and generally cheaper. If you pop open the boxes and examine the main control board, I bet you that they are all pretty much identical. Procedure is the same if you get a Honda box or whatever. You gotta go in and remove those same resistors. Just trace them back and check for continuity from the pin at the connector outside the box.
I am down with opening up the box and changing around the resistors, buts its the wiring diagram I am kind of worried about. I don't know which pins would go to which wire. I remember reading somewhere that you were going to come out with a 2001 wiring diagram for the aem ems. never did find it. Want to hook a brother up?
 

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Discussion Starter #11
Well, I own a GS not an IS. All the diagrams I have are for the GS lol. It's really not too difficult to find the right pins if you have the diagram. Look around here on this forum, I know I've seen a very detailed digram of what every pin on the IS ecu does. Then for the AEM part just look up the diagram for the specific box you bought. If you download the AEMPRO software, it has the pinout diagram for every box aem ever made in the folder of the AEMPRO software. Just look in the IS diagram and then the AEM diagram. Match up injector 1,2,3,4,5,6 then coil 1,2,3 and crank/cam....etc. It's not too difficult since theres only about 25 wires or so that you need to hook up to the AEM.
 

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Is there anyone who used 30-1050 for 2JZ-GE VVT-i setup with most stock sensors successfully?
What kind of mods you made for the unit?
 

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Discussion Starter #13
Most people that run the AEM here use the 1050 Honda box and use all the stock sensors. It just takes a while to calibrate the sensors perfectly. All AEM boxes are pretty much the same, the main difference being the wiring harness.
 

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Most people that run the AEM here use the 1050 Honda box and use all the stock sensors. It just takes a while to calibrate the sensors perfectly. All AEM boxes are pretty much the same, the main difference being the wiring harness.
Where do you get the harness that will plug into the IS300?
 

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Most people that run the AEM here use the 1050 Honda box and use all the stock sensors. It just takes a while to calibrate the sensors perfectly. All AEM boxes are pretty much the same, the main difference being the wiring harness.
Thanks JeffTsai for quick reply!

I shall make harness myself, it is clear.
They do the same changes inside the box as you inside 1313 box?
(same resistor numbers?)
Do you know any details about this changes in 1050 box?

Thanks in advance.
 

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Discussion Starter #17
The harness you can buy from Boomslang Fabrication...at least that's where I bought it. Say if you buy a Honda Civic box, goto the Boomslang website and order the harness for the specific AEM box you bought. As for internal modifications, I can't say 100% for sure if they will be the same resistors...but it SHOULD be. Best way to make sure is to have a multimeter with a continuity tester function and test it. Put one lead from the meter to the pin on the harness side the case for the corresponding sensor, and the other lead to the resistor. If it shows continuity then it's the correct one.

Also, keep in mind the AEM uses a 3 layer PCB with the middle layer providing a 5V source to several of the components on the daughterboard. Make sure you're not getting the middle layer when you test continity because that won't be the correct sensor. Think of that middle layer as a common ground(but it's actually a common power source). So basically there will be several points on the board that will show continuity if you probe into the 5v circuit.
 
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