How to Install a HKS FCD

How to Install a HKS FCD


The install of the HKS FCD is straightforward procedure, and can be installed by any average mechanic.

The HKS FCD is an electronic device developed to properly raise the factory fuel cut level, on factory turbocharged vehicles, to a safe and higher predetermined point.


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

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

  • 1 FCD 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

Before you begin the install it is a good idea to read through all the applicable information and directions that come with the FCD.

The first step or the install is to disconnect the negative terminal from the battery. This ensures that there is no possibility of accidentally shorting any electrical devices.

Next we find the location of the stock Computer. In this install it is in the trunk of our Toyota MR2.

We then carefully remove the necessary panel(s) that protects the computer.

For the MR2 it is flat panel, in the trunk, against the wall that separates the trunk from the engine.

There are four plastic interior fasteners across the top of the panel, which secures it in place.



Here the 2 Left ones are already removed; the computer is right behind this panel.

Now that the panel is removed the computer is easily accessed. Some people wire it in without removing the computer, but I find it much less troublesome just removing it completely during the install.

To do this you simply remove the 3 10mm bolts that secure the computer. Then remove the wiring harness from the computer by depressing the tab on the top of each wire connector. There are 3 connectors for the MR2.



Now that the wires are easily accessed we start installing the FCD unit itself.

Look into the directions for the FCD for the appropriate diagram for your application. There are 4 wires on the FCD unit

Yellow – Computer side of pressure sensor
White – Sensor side of pressure sensor
Black – Computer Ground
Red – Computer power

Find the location of the pressure sensor wire. On the MR2 it is the Blue wire with a black stripe on the small, middle, harness. Cut this wire leaving ample room on each side to crimp on the bullet style connectors. Make sure you crimp on the correct connector that mate with the appropriate wire.

Next is to locate the Computer power wire, Black with yellow stripe on the MR2, and use the quick connect to tap in the red wire of the FCD.

Now locate the Computer Ground wire, Thick Brown on the MR2, and use the quick connect to tap in the black wire of the FCD.

It’s a good time to set the FCD unit to the appropriate channel. Refer to the FCD’s directions for the appropriate channel for your application. In our case it was channel 7. The Dial rotates easily with the aid of a small screwdriver.

Okay we’re almost there. Now plug the harness back into the Computer and bolt the computer back in.

Now mount the FCD unit next to the computer utilizing the double sided tape. Use the 2 tie straps to tidy up your wiring.



Note: the Extra wire loom is to a APEXi AVCR boost controller Installed previously.

Finally put the interior panel back on and your all done.

Make sure you have your settings correct on the dial and connected to the setting that HKS recommends for your vehicle.



  1. Most try put mine in now how would I no what setting to put it at for my car it’s a 92. 3sgte engine if u can help that would be great thanks Alan