4AGE Swap with MSnEDIS Standalone: '89 MR2
This swap has an interesting story with many twists and turns. The engine involved is a 4AGE Silvertop from Japan. It was originally intended for a '91 Geo Prizm. After the owner, Aaron, decided that the Prizm needed too much work for this to be swapped in, he decided to instead pick up an '89 Toyota Corolla SR5. About this same time he contact me to get the engine swapped in. I drove down and picked up the engine personally, and some things I found were not good. The engine harness was cut, there was no ECU, coil, ignitor, or distributor cap. After conferring with Aaron and talking about what his goals for the future of this car were, we decided the best route would be to forgo trying to find the stock Toyota ECU and ignition system, and go full standalone instead. To save on money, we chose the open-source "Megasquirt" system, with modifications to use the Ford EDIS ignition system. Around this same time, Aaron got a good deal on an '89 Toyota MR2, and instead of putting this great setup into an old, carburated FWD car, he decided the MR2 would be a much better recipient. Good decision, Aaron.

I assembled the MS system, and here I'm testing it with a laptop.




Now that all those electronics are out of the way, it's on to the dirty work.

Here's the best way to drop an engine out of an MR2: Out the bottom!




Before installing the 20v 4AGE engine/tranny assembly,
the shifter linkage needs to be modified for midship mounted use.


Then the engine is lifted into the car and bolted in place.




In order for the ignition system to be installed on this car, a 36-tooth wheel must be attached to the crank pulley,
and custom bracket made for a VR sensor to sit in just the right spot.
There is about 1mm of clearance between the sensor and the wheel.


A custom aluminum block-off plate is made and installed where the distributor used to be:


A custom wiring harness is made, using parts from the 4AGE, the MR2, and then the EDIS and MS wiring...


Several custom cooling hoses are run, and all the mechanicals on the engine completed.


At this point in the story, I made a move from northern Vermont, to Savannah, GA. Since this project wasn't done yet, and I had an opportunity to tune it on an in-house dyno in my new shop, I towed it the 1200+ miles down with me. After getting moved in, I finished hooking the standalone up and got it started on the first try. However, after trying to move it around under it's own power, I found that the clutch was completely shot.

I quickly dropped the tranny and installed a new clutch


Once that was done, it was off to the exhaust shop for a custom exhaust!


Once the exhaust was completed then it was a few days of solid tuning using a wideband A/F ratio meter and the various MS tuning and datalogging software. Then Aaron made the flight down to Savannah, and promply drove his car the 1200+ mile trip home incident-free!

For more information on the Megasquirt EFI System, please visit http://www.msefi.com/

A complete discussion of this swap can be found here
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