How to Install a SAFC in a MR2

How to Install a SAFC in a MR2


The second generation MR-2 is one of the classics in import sport compact vehicles, and while it’s production run was cut short by Toyota it’s still a very attractive package for anyone looking for turbocharged RWD performance. With the 2.0L turbocharged 3SGTE, and a bevy of features such as a viscous LSD, upgraded twin synchros and the ability to squeeze more power out of the 3SGTE, the MR-2 is still very relevant in the annals of sport compacts.

Today we’ll be installing a SAFC into a 1993 Toyota MR2, with a host of other parts such as the HKS FCD. Along with our How to Install a SAFC in a MR2 install, we’ll be going over the setup points as we get this unit installed and our MR2 strapped to the dyno.

This install of a Apexi Super AFC is a very simple procedure and can be performed by anyone with a decent amount of technical skill or soldering ability. If you are not confident in your ability or do not know How to Install a SAFC in a MR2, we recommend taking your vehicle to an experienced mechanic.

Tools Needed:

  • Wire Strippers or scissors
  • Pliers
  • 10 mm socket and handle

The AFC unit is accompanied with all the hardware necessary for the install.

  • 1 AFC Unit
  • 2 quick splice wire connects
  • 1 male bullet style connector
  • 1 female bullet style connector
  • 1 square piece of double sided tape
  • 2 tie straps

Take this time to familiarize yourself with the kind of wiring setup you will need to do on this How to Install a SAFC in a MR2 guide, as this vehicle is MAF driven, here is the datasheet for you to review.



Now, disconnect the negative terminal on your battery to prevent any possibility of a short or electrical problem. After doing so, open your trunk to locate your PCM for your vehicle located behind the panel behind the cabin. To remove the panel and access the ECU, you must undo the four plastic pop rivets located across the top of the rear panel that holds the panel in place.

With the ecu removed, take some time to familiarize yourself with the wiring diagram, located here for the SW20 MR2



Unfortunately for most owners, the MR2’s ECU location makes it a difficult task to wire and mount your AFC in any sort of useable manner. First and foremost, find which wires you will be using, and extend them a good 8 feet at least. Once you have done that, run the wiring harness into the trunk and mount your AFC, make sure you leave enough wire so that you can comfortably solder and modify your harness.

The extending of wires is a crucial step to our How to Install a SAFC in a MR2 article, make sure you solder each extension.

First locate the RPM wire on your MR2’s ECU layout. The wire that provides RPM signal to the ECU is labeled IGF ( or ignitor pinout ) Tap the Green Wire of the SAFC into that wire.



Next locate the ground wire off the ECU. This wire is labeled E1 in our pinout picture. Tap the brown wire CLOSER to the ECU, but leave enough room for another tap on the same wire. Then tap the black wire further down on the same wire. Remember to tap the engine ground with this arrangement. Improper install can lead to problems.



Locate the red wire on the SAFC loom and tap that into the power wire on the ECU, which is labeled + B for the Main EFI Relay. This will complete the power section of our How to Install a SAFC in a MR2 writeup.



Next locate the A/F Wire, which is labeled VS for Volume Air Flow Meter. Our car is setup for Flapper style of Mass Air meter.



Cut this wire in half, leaving enough space to operate on both ends because this is the Karman wire or the sending wire for your MAF. Solder or tap the yellow wire into the ECU side of the unit.



Then Solder or tap the White Wire into the harness side of the unit.



Locate the Throttle Wire labeled VTA on our pinout. Tap the gray AFC wire into this wire.



This customer wanted to tap his 02 wire as one of the optional outputs, otherwise known as the BLUE WIRE MOD. If you do not know How to Install a SAFC in a MR2 affects the blue wire mod, please click the link above.

FYI: We usually dont recommend this. For this function, locate the OX wire on the pinout, and tap the blue AFC wire into that. For more information about the optional output for the BLUE WIRE MOD, click here.



You have completed our article on How to Install a SAFC in a MR2 as well as the install of your AFC into your MR2!!

With the physical part of the install done now, you can now enter into the etc and menu to setup your AFC.



Set the Meter type to FLAP, then set the IN / OUT to the value 2.



Now set the cylinder type to 4 cylinder and you are ready to tune!


Please let us know if you have any questions or comments below!


Happy Tuning!