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INTRODUCTION:
The replacement digital ECU is designed for reliable repeatable performance. Because the ECU utilizes digital electronics, it is not
affected by variations in temperature or humidity.
The Digital ECU has adjustments for Choke, Acceleration, Idle, Main, and High RPM settings. By simply dialing in the appropriate fuel
curve, fuel delivery can be accurately matched to the engine’s requirements across its entire power band.
The ECU is factory-programmed with fuel maps for both small block and big block engine applications and controls the amount of fuel
delivered to the engine by pulsing each of the two fuel injectors for precisely controlled periods of time. The rate and length of time at
which the injectors are pulsed is calculated from various inputs such as engine speed, throttle position, engine coolant temperature, and
an optional oxygen sensor.
Although the digital ECU is pre-programmed at the factory, the amount of fuel delivered to the engine under various operating
conditions is user-adjustable through the use of five adjustments knobs located on the front panel of the digital ECU. These adjustment
knobs are used to tune the system.
WARNING! The Digital Replacement ECU system is NOT recommended for high-speed, high-performance engine
applications.
WARNING!
This ECU is NOT to be used for MARINE or AIRCRAFT applications.
Pro-Jection 2D Fuel Injection System -- Overview
Figure 1
NOTE:
Although every possible precaution was taken in the design of the digital ECU to prevent interference from radio sources, the
use of solid core spark plug wires may interfere with the operation of the ECU. Holley recommends the use of either
suppression or spiral wound spark plug wires, such as Holley Part #’s 50-9800, 50-9801, or 50-9804.
NOTE:
Installation of the optional Closed Loop Kit on a vehicle equipped with emissions control devices, such as an AIR pump, may
cause extremely rich fuel mixtures, resulting in possible damage to your engine. Federal Law prohibits the disconnection of
AIR pumps. Ensure that all local, state, and federal laws are adhered to when any modifications are made to the emissions
control devices on your vehicle.
