Here's how I pass inspection with my AEM EMS ~500 AWHP EVO 8

[Blue Evo 8]

Hello all,


I have a 05 EVO which I have had AEM EMS on it since I got the car. Each year, I've gone thru the hassle and trouble of converting back to the stock ECU in order to pass OBD2 inspection, and each year I have learned new things, as well as becoming faster and more efficient at converting back and forth.

In this post I just wanted to share my notes with everyone so that it may help others make the switch confidently.

So what have I learned in the past 4 years?

To convert back from your AEM EMS to the stock ECU:

1) reinstall the stock MAP sensor. You can leave your 5-Bar AEM MAP sensor in place, just remove the AEM Map sensor connector so that you can reinstall the stock one. There are 3 wires that I unsolder and resolder here. the wires are for the stock MAP sensor socket/plug. The 3 wires involved are grey, black and yellow.

2) If you are running speed density as I am, you need to resolder 2 wires back onto the original position it came from on the MAF harness/plug. The two wires are black, and blue/green I think. Reinstall your OEM MAF along with a hi-flow filter.

3) I am running 1000CC precision injectors.... here I have to put the stock injectors back in. To make life easier, I broke the tabs that secure the fuel injector clips onto the injector in order to slide the clips in and out faster. Remember when installing injectors pull them out carefully or else you will damage the rubber o-rings which make the seal between the injector and the fuel rail. Additionally, when you swap in new injectors dont forget to coat the rubber o-ring with a coat of clean motor oil.

4) Plug in the stock ECU anytime. Additionally, I am running the SMC V2 Meth injection kit. There is a power wire from the Meth injection kits harness which splices into a red wire on the ECU harness....In the past, I disconnected this and resoldered the stock wiring together, but I learned from experience that doing this is not necessary. All you need to do is remove the AEM box and put your stock ECU in....

5) Camshafts? In the past I would remove my HKS 280's since it caused me to throw a P0172 code. This was due to the fact that I had the cams set at 0,0.
Today I've experimented, left the cams in place and left it at my +2 intake, 0 exhaust setting, started the car and threw no code. Here I am really pleased that I can save time by not having to touch my cams at all....

6) Walboro 255LPH fuel pump....In the past I would put the stock fuel pump in, but this also is not necessary...again more time saved by skipping this step.

7) I am running Buschur Racings EGR valve aluminum blockoff plate, in this step you have to reinstall the stock EGR valve and reconnect the vacuum lines.

All in all my car is ready to go for inspection, minus the fact that I need to go around the block a few times to complete a drive cycle or two to get all the monitors that I need to be in the "ready" state. In the state I live in they allow 2005+ OBD2 cars to have one monitor in the "not ready" state in order to pass.


Comments and questions are welcome. Later on I might put up some pictures to illustrate the steps I've gone thru. All in all, with a few breaks, lunch etc in between, and with no set-backs, I can convert my EVO to be emissions testing ready in a matter of 3-4 hours.

[althemean]

sounds like a normal re-conversion. Good info though. Do you have lots of mods and what about a retune on the stocker ecu?

Mine is set up just as easy to reconvert...but I dont know what will happen with the JUN 264's. They idle like so..so on the aem. But that prob is due to the summer heat. I havent retuned for that yet...I know DB runs his project white with the stock ecu and jun 272...or that was what the thread said months ago.

On another note I believe DB also runs speed density on that car with the stock ecu.

[whoflungpoo]

If you're having to swap it that often, I would consider not cutting off the stock connectors for your map and maf. when I bought my car, it already had the AEM installed. The stock maf connector was still attached, the IAT was simply spliced into the stock wires, so if I wanted to run a maf, all I would have to do is disconnect the IAC, and plug in the MAF, as either one being unplugged will leave it in an "open" state and will be inconsequential to the readings. same goes with your AEM vs stock MAP sensor.

by doing this, it takes the soldering completely out of the equation, and it would bring it one step closer to being a simple plug n play swap.

[BlueEvo61106]

It should be fine running the JUN 264's on a stock ecu. I was running HKS 264's on my stock ecu and was fine.

[Blue Evo 8]

Originally Posted by althemean

sounds like a normal re-conversion. Good info though. Do you have lots of mods and what about a retune on the stocker ecu?

Mine is set up just as easy to reconvert...but I dont know what will happen with the JUN 264's. They idle like so..so on the aem. But that prob is due to the summer heat. I havent retuned for that yet...I know DB runs his project white with the stock ecu and jun 272...or that was what the thread said months ago.

On another note I believe DB also runs speed density on that car with the stock ecu.

yeah, it is the normal reconversion, but I have managed to elimate a lot of time consuming steps thru trial and error in the past few years. What I am going to do now to make life even easier is have my stock evo 8 ECU flashed to handle my 1000cc injectors, so that i can totally eliminate that whole process of swapping injectors.

Yes i do have a lot of mods....HKS 280's, Meth injection, AEM EMS, AMS 50 trim turbo kit, full 3" exhaust, ARP Headstuds, Buschur Race FMIC...pretty much all the supporting mods to max out my 50 trims output.

[Blue Evo 8]

Originally Posted by whoflungpoo

If you're having to swap it that often, I would consider not cutting off the stock connectors for your map and maf. when I bought my car, it already had the AEM installed. The stock maf connector was still attached, the IAT was simply spliced into the stock wires, so if I wanted to run a maf, all I would have to do is disconnect the IAC, and plug in the MAF, as either one being unplugged will leave it in an "open" state and will be inconsequential to the readings. same goes with your AEM vs stock MAP sensor.

by doing this, it takes the soldering completely out of the equation, and it would bring it one step closer to being a simple plug n play swap.

I know what you are saying here, but for me its already too late. When my tuner installed my AEM he did what he did, so now, I'll have to spend a few minutes here and there to resolder 5 wires when inspection time comes. Its not bad, and I dont mind doing the soldering on a boring weekend afternoon.

[evodan2004]

blue evo 8

why dont you just ditch the AEM all together with how far the ecuflash forum as come AEM is not needed for 500/550hp. i pass nj state inspection just fine with big cams, 1200cc injectors, no cat or rear o2 sensor, no evap or egr stuff and other stuff. no cel light. if your going through all this swapping trouble with aem to stock ecu you really need to read up on the new age stock ecu stuff. and you can run SD now too. so its even better. just a thought.

[althemean]

Originally Posted by BlueEvo61106

It should be fine running the JUN 264's on a stock ecu. I was running HKS 264's on my stock ecu and was fine.

No offense man...but Jun and HKS are very different.

Although after reading DB's thread on his white car. He makes the stock ecu run Jun 272's and speed density. Unless I misunderstood something. I would switch back to the stock ecu and may still do that. I just wish these good tuners were on the west coast.

[Jeovannie]

Another way is having on of your boys plug their car with the stock ECU. I'm not saying I did it that way

[project_skyline]

lol sounds like a big pain in the ass.

[JDMK20EGALLDAY]

Sounds good man beats switching whole thing back to stock

[raiceboi697]

and thats why i like the loophole i found

[Nastynine]

hope to run AEM ems but am NOT looking forward to this process.

nice thread though, gives a good explanation. well done

[Blue Evo 8]

Originally Posted by Nastynine

hope to run AEM ems but am NOT looking forward to this process.

nice thread though, gives a good explanation. well done

but you get used to it. I have it down pat now, and could convert back to "pass" in a matter of a couple hours... no biggie...

[gordata]

Damn you need to come down to the bronx. Seems like a big thing to go thru every year.