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Unpacking & Inspecting Your Kit

Be sure to read the packing slip because the as-shipped configuration tells you which transmission your COMPUSHIFT II is programmed to operate with – as well as what torque converter lockup and maximum upshift RPM rules are programmed into the unit.  It will also tell you which of the optional components and wiring harness was included.

When you ordered COMPUSHIFT II, you had to choose from one (1) of three (3) Throttle Position Sensor (TPS) systems:

  1. The AccuLink TPS for vehicles with Edelbrock AFB, Holley and Rochester Quadrajet carburetors; or
  2. A wiring harness for Electronic Fuel Injection (EFI) vehicles that have their own TPS; or
  3. A Cable Operated TPS for all other engines, including older diesel engines

Please contact your distributor or HGM headquarters right away if you're missing the required part(s) for your specific TPS system.

All necessary wiring harnesses and TOSS adapter cables are included with your basic COMPUSHIFT II.

Here's what's in a COMPUSHIFT II kit:

The COMPUSHIFT II Controller

The controller is the heart of the transmission control system.  On its exterior, you will see:

  • Five (5) connectors for wiring:
    • Two (2) for the transmission wiring harnesses
    • One (1) for the power wiring harness
    • One (1) for the engine wiring harness
    • One (1) for the option wiring harness
    • One (1) for the Display cable
  • USB port
  • LED indicator showing "power on" and system status
  • SD card slot

The Display

The display is designed to work specifically with your COMPUSHIFT II Controller.  It connects to the Controller via the attached cable.

You will use the Display to perform initial system setup and also to view readouts as you operate your vehicle.

For more information on the COMPUSHIFT II Display and all of its screens, visit Monitoring & Tuning Your System section.

Transmission Wiring Harness

The Transmission Wiring Harness, shown here (or one similar), connects the COMPUSHIFT II Controller to the transmission.

See here for installation instructions.

Power & Engine Wiring Harness

The Power & Engine Wiring Harness, shown here (or one similar) connects the COMPUSHIFT II Controller to the vehicle's TPS, tachometer, speedometer and power.

See here for installation instructions.

Each harness has a rubber grommet for the firewall. These are placed in a recommended spot, but can be repositioned.

Hydraulic Pressure Sensor Harness (Optional)

The Hydraulic Pressure Sensor Harness, shown here, connects the COMPUSHIFT II Controller to the transmission's hydraulic pressure sensor port.

Switch-Shift Harness

COMPUSHIFT II includes the option to connect the Switch-Shift feature, allowing you to manually upshift and downshift via pushbutton controls or paddle shifter.

Switch-Shift uses an additional Switch-Shift Wiring Harness (see photo) that connects the Transmission Wiring Harness with the pushbutton controls.

See here for installation instructions.

The Acculink TPS (Optional)

Acculink TPS fits all Edelbrock AFB, Holley and Rochester carburetors.

  • The sensor is a spring-loaded, fully sealed rotary position sensor specifically designed for automotive use.
  • All linkages, brackets, screws and nuts are made of stainless steel for corrosion resistance and longer life.
  • The linkage and brackets are laser-cut for extreme accuracy.
  • The sensor mounts directly to the carburetor and connects via a metal linkage. This eliminates installation and calibration difficulties that can occur with cable-driven sensors.

The Acculink Kit includes the following parts:

  • Sensor bracket
  • Ratio arm
  • Adjustable arm (2 pieces)
  • Two 10/32" x 7/8" Phillips pan-head screws
  • Other mounting hardware (stainless steel nuts, washers, brackets and screws) 

The TPS Connector for an Electronic Fuel Injection (Optional)

For an Electronic Fuel Injection Engine with a standard GM TPS

Most EFI engines have their own built-in Throttle Position Sensor (TPS), and you'll only need our provided adapter harness to tap into the signal. You will not need an Acculink TPS or Cable TPS..

No advance assembly is required for this adapter harness. You will install it later, in this step along with the Power & Engine Harness.

For a diesel EFI engine, you will need to tap into the pedal position sensor signal. Consult your distributor or HGM for advice on this.

For other types of Electronic Fuel Injection engines

In installations where the EFI does not use the standard GM-style TPS, you will need the Universal EFI TPS wiring loom, shown here.

This loom has three leads that should be spliced into the appropriate signals on the EFI. The loom's connector plugs into the Power & Engine Harness, according to the instructions on this page.

Cable Operated Throttle Position Sensor (Optional)

If you have a mechanically-actuated throttle that cannot accommodate AccuLink TPS, HGM Automotive Electronics offers a Cable TPS and Sensor Box. 

The parts in the kit are shown in the photo.

To install, follow the instructions on this page: Install the Cable-Operated TPS

Our Cable TPS and Sensor Box use the same sensor as the AccuLink TPS and can provide the signal necessary to shift the transmission.

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