Publicidad
Idiomas disponibles
Idiomas disponibles
Operating the RAMJET engine at very low engine RPMs and low vacuum conditions is also not desirable
from a fuel economy standpoint. The RAMJET electronic fuel injection system is a speed and air density
system ("speed density" fuel management). Sensors provide the ECM with the basic information for the fuel
management portion of its operation. Signals to the ECM establish the engine speed and air density factors. The
engine speed signal comes from the Ignition Control (IC) module. The ECM uses this information to determine
the "speed" or RPM factor for fuel and spark management.
The Manifold Absolute Pressure (MAP) sensor contributes the density factor. As intake manifold pressure
increases, the vacuum decreases. The air density in the intake manifold also increases as additional fuel is
needed. The MAP sensor sends this pressure information to the ECM, and the ECM increases the amount of
fuel injected, by increasing the injector pulse width. As manifold pressure decreases, the vacuum increases, and
the amount of fuel is decreased. These two inputs, MAP and RPM, are the major determinants of the air/fuel
mixture delivered by the fuel injection system. The remaining sensors and switches provide electrical inputs to
the ECM, which are used for modification of the air/fuel mixture, as well as other ECM control functions, such as
idle control.
This package is designed to provide a completely calibrated fuel injection system for the 502/502 crate engine.
This system will provide a number of benefits over a carbureted system. These benefits include improved
driveability, better fuel economy, and increased performance across the entire RPM range. These benefits are a
result of the precise fuel and ignition control across the entire RPM range.
All of the spark and fuel management functions are handled through the ECM. It is the control center of the
fuel injection system. The ECM controls the fuel metering system, ignition timing, idle speed, and on-board
diagnostics for engine functions. It constantly looks at the information from various sensors and controls the
systems that affect engine performance. The ECM also performs the diagnostic function of the system. It can
recognize operational problems and store diagnostic trouble codes, which identify the problem areas to aid the
technician in making repairs. Refer to the Big Block RAMJET service manual, part number 88962724, included
in this kit, for more information on using the diagnostic function of the ECM.
The ECM controls spark advance for all driving conditions. It monitors input signals from the following
components as part of its ignition control function to determine the required ignition timing:
• Ignition Control (IC) module
• Engine Coolant Temperature (ECT) sensor
• Manifold Absolute Pressure (MAP) sensor
• Throttle Position (TP) sensor
• Knock Sensor (KS)
The function of the fuel metering system is to deliver the correct amount of fuel to the engine under all operating
conditions. Fuel is delivered to the engine by individual fuel injectors mounted in the intake manifold, near each
cylinder. The ECM looks at inputs from several sensors to determine how much fuel to supply to the engine. The
fuel is delivered under one of several conditions, called "modes". These modes include starting mode, clear flood
mode, run mode, acceleration mode, fuel cutoff mode, and RPM reduction mode. The ECM controls all of these
modes. Refer to the RAMJET service manual for more information on the ECM and the characteristics of each
mode.
It is not the intent of these specifications to replace the comprehensive and detailed service practices explained
in the factory service manuals.
88962910
2
54
Ramjet 502 Engine
IR 17FE14
TITLE
PART NO.
SHEET
OF
Publicidad
