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The A/F tuning module is designed to allow air fuel corrections on modified fuel injected engines. IE,stroker / big bore engines, high flow cylinder heads, performance camshaft, and performance exhaust systems. It is especially useful for lean fuel programming under cruise conditions with the stock engine management system (ECU). It is best to restore all previous modifications to stock settings; air flow meter, timing, injector sizing, and with the aide of a mixture meter established, a safe A/F ratio under all driving conditions. Pay particular attention to the light throttle cruise condition at highway speeds, then go ahead and tune the airflow meter and ignition timing for best acceleration.

The Pro Air Fuel Tuning Module operates by allowing the computer to think that the engine is cold and then broadens the pulse width of the four injectors. The Pro Air Fuel Tuning Module will richen the mixture only. If the engine is running in a rich condition without the tuning module, a tuning issue could exist and proper diagnosis from a certified mechanic will be required.

Installation Instructions:

    1. Disconnect the battery

    2. Locate a suitable location to mount the A/F module inside the cab where it is easy to make adjustments.

    3. Remove the right side kick panel to access ECU harness

    4. Carefully remove 4-6 inches of protective tape at the ECU harness sockets.

    5. Locate the “THW” wire and cut the wire approximately 2-3 inches from the socket.

    6. Strip 3/16 inches of insulation and splice each leads from the module to each end of the cut “THW” wires with the supplied terminals, and shrink tubing.

    7. Determine the optimum position with the use of a mixture meter or until you gain a slight RPM increase at idle. If the engine hesitates, misses, smokes, or the “Check Engine” light comes on, it is too rich. Reduce your adjustment.

NOTE: It is preferable to use an Ohm meter to verify the “THW” lead. You must disconnect the ECU multi-plug and back probe the coolant sensor socket (green sensor below thermostat) and “THW” lead at the ECU. See attached application table below for your particular vehicle.


NOTE: Coolant Temperature Sensor Terminal (THW Pin) Is Blacked Out For Location Identification