ProEFI Install Guide by Josh S

By diyauto
( 3 )

15 minute read

ProEFI Install Guide 

Compliments of Josh S @


I have been working on this guide during the install of my ProEFI and now that I've confirmed that everything is working ok I've decided to post it here. DaveT has posted a great install guide over in the SP section. We did a few things a bit differently so I figured I might as well put mine out there as well in case it helps someone.


The following guide is how I connected my ProEFI 128 system into my 1995 6-Speed. I cannot confirm that the wire colors and connectors are the same for obd2 Supras.

Installation tips:
I perfer to solder and heat shrink all connections
The pins for additional wires to the ProEFI harness can be crimped with pliers and then soldered
Instructions for connecting the iBoost knob, CAN display cable, and wideband sensor are included with the ProEFI so I did not cover them here.

Items that can be removed:

Here is a list of some of the items that can be safely removed when the ProEFI is installed with a single turbo and upgraded fuel system.
All of the VSV’s that controlled the stock turbo system
The pressure tank and its VSV
The EGR vsv (if you have also removed the EGR system and have block off plates)
The stock FPR and FPR VSV
The fuel pump ECU
The stock turbo pressure sensor

Traction control:

For the traction control connections to the wheel speed sensrs must be made.

Driven Wheel Speed Input (J1 A01)
Non-Driven Wheel Speed Input (J1 A12)
Wheel Speed Return (J1 A32)

The wheel speed sensor wires can be accessed at the ABS ECU which is behind the radio. After removing the dash panels and radio, locate the ABS ECU.

Toyota Supra A80 dash removed locating ABS ECU

You need to get to the two left plugs shown unplugged here:

ABS ECU location

Unplug all three connectors and pull back the carpet on the drivers side to allow you to pull the harness out the side of the center console. You need to make connections to the White wire (Front LH sensor wire Pin 5) on the large connector and the purple wire (Rear LH sensor wire Pin 9) on the smaller connector and the light green wire (Return pin 1) smaller connector.

Toyota Supra A80 wire plugs in the ABS ECU

reconnect the three connectors to the ABS ECU and run the two tapped wires to the ProEFI harness.

Connect the shield ground to a good ground near the ABS ECU. You can see I connected the shield to the bolt on the left in this picture.

ABS ECU plugged in with wires tapped into ports

Connect the wire connected to the white wire to (J1 A12), the wire connected to the purple wire to (J1 A01). Splice the wire connected to the light green wire (return) to (J1 A32). Note that for some reason my harness came with these two line already connected to the ECU harness as if I had an automatic transmission. Just remove the wires from the ProEFI connector and insert the two wires from the speed sensors.

Wires inserted into speed sensor plug

Trac Switch Input (J1 C11)
Trac Active Light Output (J2 B21)
Trac Enabled Output (J2 B02)

The TRAC Switch, the “TRAC OFF” light, and the “TRAC” light, and can all be wired to the connector that went to the stock TRAC ecu right next to the main ECU. There is a 26-pin connector here. Connect (J1 C11) to the light green wire, pin 5. Connect (J2 B21) to the White wire pin 24. Connect (J2 B02) to the light green/red stripe wire, pin 23.

Below is the connector from the TRAC ECU.

TRAC ecu plug

Here are the three wires I connected to:

connected wires from harness

Note, you must also cut the light green/red wire at the ABS/TRAC relay box on the passenger side of the engine bay. I do not have a picture of this. If this wire is not cut, the "TRAC OFF" light will be forced on all the time.

MAP sensor:

Install the pressure sensor into the intake manifold where the stock filter nipple was installed:

Pressure sensor mounted on intake manifold of Toyota Supra

Note you may have to run a 1/8" NPT tap into the intake manifold as I believe the stock threads are slightly different. Also use some teflon tape or thread sealer on these threads.

The pressure sensor has three wires to connect:

Red = 5V reference
Black = Ground
White = Signal

The ProEFI harness connects (J1 A29) to ECU pin B62 which goes to the stock pressure sensor connector. Locate the stock turbo pressure sensor connector:

Toyota Supra A80 turbo pressure sensor plug

Make the following connections:

Red to Blue/Red stripe
Black to Brown/Black stripe
White to Black/Yellow stripe

connections into wiring harness

Fuel Pressure Sensor:

I installed the Fuel Pressure sensor directly to the unused port on the FPR using a MagnaFuel -6AN to 1/8NPT adapter (Part number MP-3071).  

Fuel pressure sensor with adapter fitting

Use thread sealer on the NPT threads of the pressure sensor.

FPR Installed to extra side port of FPR here:

Fuel pressure regulator installed in engine bay

The pressure sensor has three wires to connect:

Red = 5V reference
Black = Ground
White = Signal

I decided to re-purpose the stock secondary trac throttle position sensor harness for the fuel pressure sensor.

Picture of connector:

stock throttle position sensor plug

Make the following connections:

Red to Blue/Red stripe
Black to Brown/Black stripe
White to Yellow/Blue stripe

connections from repurposed plug for fuel pressure sensor

The Yellow/Blue stripe wire connects to ECU terminal B42. At the ProEFI harness connect the wire from ECU B42 to ProEFI pin (J1 A30), by crimping a pin to the ECU lead and inserting it into the ProEFI connector housing.

Picture of pin crimped and soldered to the B42 wire:

Picture of pin crimped and soldered to the B42 wire

IAT Sensor:

I installed the IAT sensor low on the IC pipe that goes to the throttle body.

The ProEFI harness connects (J1 C12) to ECU pin B45 which goes to the stock MAF plug. Conect the IAT sensor to the Pink/Blue stripe (signal) and the Brown/Black stripe (ground).

Below is a picture of the two IAT wires from the MAF connector that have been re-routed to the throttle body side:

 two IAT wires from the MAF connector that have been re-routed to the throttle body side Toyota Supra

Here is where I mounted my IAT sensor. It is a NPT thread:

IAT sensor location

Note that the pins for the IAT sensor are inserted into the front of the supplied connector. This means you must pass the wires through the connector before crimping/soldering the terminals on:

Wires through the IAT sensor and crimped after

Boost Control Solenoid:

The ProEFI harness connects (J2 B18) to ECU pin B60 which goes to the stock wastegate VSV. The wires are Black/Red stripe (power) and Blue/White stripe. It does not matter which wire goes to which side of the solenoid.

These wires exit at the front of the spark-plug cover (near the water neck).

Picture of wires:

wires blue and red

First you need to crimp the contacts onto wires to mate with the connector that comes on the solenoid. Put the green rubber boots on and crimp then solder the contacts as pictured:

wire with green boot and crimped connecter end

Insert the pins and close the connector cover:

wire pins inserted and boots inserted into connector

Solder this cable to the stock wires. I routed the cable under the spark plug cover to the rear of the valve cover and out along the firewall:

wires routed in engine bay

Here is where I mounted the solenoid:

solenoid mount location

Fuel Pumps:

I decided to wire the relay’s directly to the ProEFI individually, as this allows for staging of the fuel pumps so that only one pump will run at cruise and light load and the 2nd will come on at higher load where it is needed.

At the connector for the stock fuel pump ECU, connect the purple/white stripe to one relay coil and the green to the other relay coil. The opposite sides of the relay coil should both be connected to the switched 12V feed which is the blue/orange stripe wire.

At the ProEFI harness move the pin from (J2 B07) to (J2 B17). This will connect the ProEfi outputs LS05 and LS07 to the two wires we tapped into at the fuel pump ecu. Note that these are low side outputs, meaning they connect to ground to turn on.

The green wire is ECU pin A21, and the purple/white stripe is ECU pin A22.

(Again my harness had a wire already in the (J2 B17) terminal which is used for an auto transmission, for a 6-speed just remove this pin)

Methanol Injection

After a lot of research and thinking about my methanol injection system I decided to purchase an AEM injection monitor gauge to use in conjunction with the ProEFI as a failsafe measure.

I am using the ProEFI to progressively control my meth pump and adjust the fuel trims and the AEM monitor will provide feedback should anything go wrong. The AEM monitor has a flow meter that is installed before the meth nozzle. Once it is all installed you can connect the gauge via USB and run a baseline injection flow rate vs. duty cycle curve. You then set high and low limits around this baseline.

For example a clogged nozzle will show up as low flow and trip a fault, likewise a high flow (popped off hose) will trigger a high flow fault. I connected it so that a fault will automatically change my iBoost setting to 1 (base boost) and tell the ProEFI to turn off the meth injection thus removing the meth fuel trims. The system is wired is such a way that anytime the ProEFI is calling for meth (pulsing the output to my solid state relay) the AEM monitor will see it and check for the correct amount of flow. This is true even if the fuse, relay, or pump goes bad.

My connection schematic is below:

Meth injection connection schematic

Now on to the install of the gauge itself. I decided to install it to the left of the steering wheel where the dimmer controls are. I realize that this is not a great location for visibility, but the whole point of how I've designed the system is that it will work automatically so I don't need to monitor the gauge. The whole gauge and needle also blink on a fault so it is easy to see that. I don't like A-pillar gauges and didn't want to cut any of the bracing behind the gauge panels so this was the best location for me.

I drilled a 2" hole with a hole saw:

gauge location with hole drilled in dash left of steering wheel

After a couple passes around the hole with a sanding wheel on a dremmel the gauge fit right in:

gauge installed in interior trim piece

I relocated the dimmer to below the dash here.

dimmer location on bottom of dash

I added the recommended AEM filter to the line going from my tank to the pump:

AEM filter location

Installed the flow meter right before the nozzle:

flow meter installed before spray nozzle

Ran the line from the flow meter inside the fender and inside the car to the gauge:

flow meter line ran through fender into car interior for gauge

Here is all the wiring ready for the gauge to be installed:

line for meter inside interior to connect with gauge

For the toggle switch that I can use to turn the meth on/off I found a project box I had laying around and mounted the switch to that which I then placed in the glove box. I left some room so I can add additional switches as needed (anti-lag control is one I may add)

Meth injection switch box located in glove box of Toyota Supra

Here is the gauge installed and powered up:

Testing gauge of Meth injection

Flex Fuel Sensor

For the Flex fuel sensor I bought a GM 13577394 sensor. This is the new flow-through design sensor.

For the harness I bought the following from Mouser Electronics and made it myself (I found this info elsewhere on the forums):

Delphi GT 150 series connector QTY:1, part # 13519047 (you have to remove two tabs from the sensor side to fit this connector).

Delphi GT 150 series Terminals QTY:3, Gold part# 15326427

Delphi Loose Cable Seal QTY:3, part# 15366021

For wiring I re-purposed the stock main o2 sensor wires. These run across the front of the valve covers. I re-routed these to the driver side and spliced in there.

There are four wires that went to the stock o2 sensor.

White (shielded) - Unused
Black-Red = Switched 12V, connect this to the +12V terminal of the sensor
Brown = Ground, connect this to the ground of the sensor
Black-Blue = Signal, connect this to the signal terminal of the sensor

The Black-Blue wire goes to the stock ECU terminal position B71. This should be connected to the ProEFI J1 A09. I just crimped a pin on this lead and plugged it into the ProEFI. Note that this is Digital Input 4 when setting up the Flex fuel input settings in the ProEFI.

I mounted the flex fuel sensor under the intake manifold and plumbed it into the return line from the FPR to the stock return hardline.


Here is the best I can do since I don't have a '97.

From mwsupra's post above
"For those with a 97+ doing a trac install the trac slip, trac off, and trac request wires can be found on an 8 pin connector(t16) by the trac ecu. ObdII cars do not have the 26 pin t9 connector. However the wire colors are the same as posted above."

That means that the Connect the trac_slip, trac_off and trac_request wires to the 8pin connector (t16) by the trac ECU. (J1 C11) to the light green wire. Connect (J2 B21) to the White wire. Connect (J2 B02) to the light green/red stripe wire.

As for the wheel speed sensors and the return this post: has all the pin-outs and colors for the wheel speed sensors for the various year supras with and without traction control.