Power and Ground Wiring
17
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electronic throttle control, refer to the Electronic Throttle Control section of this manual.
This wire MUST be powered in order for the ECUs self diagnostics and the Aux 9 and
10 drivers to function properly.
6.4
Power Ground
These wires supply the high current earth for the output drives. Since these wire will carry
substantial currents, ensure they are well terminated to a clean earth point on the engine
block. It is also essential that there is a good clean connection between the engine block
and battery negative terminal.
IMPORTANT!
The Power Grounds MUST be run as SEPARATE wires. DO NOT be
tempted to join them together at the ECU and run as a single wire.
Also beware of poor earth points around the engine. Some manifolds
and other attaching parts may be rubber mounted and therefore have
poor earth bonding. A good rule of thumb is to use the engine
BLOCK or HEAD rather than attaching parts.
6.5
Sensor Ground
These wires are used to supply a ground reference for the sensors used by the G4 ECU. As
such, it is ESSENTIAL that these wires are used for all sensors that require a ground (e.g.
throttle position sensor, water temperature sensor, etc.). Failure to do this may result in
unstable sensor readings causing erratic ECU operation. Do NOT be tempted to ground
sensors to the engine block unless it is absolutely necessary (e.g. single wire sensor).
IMPORTANT!
Do NOT connect any green Sensor Ground Wires to the engine
block or other grounded point. This will cause current from other
devices to flow in the sensor ground wires and may result in unstable
sensor readings. Most sensors are isolated from ground so this is
usually not a problem. Pay particular attention to this point when
connecting external controllers.
6.6
+5V Out
This wire supplies a regulated and over current pro5V to be used by sensors that
operate from a 5V supply. The most common example is a throttle position sensor (TPS)
and some manifold absolute pressure (MAP) sensors. Do NOT connect this wire to +12
volts or any other +5V supply.
6.7
+8V Out
This wire supplies a reg8V to be used for the Crank Angle Sensor (CAS) if optical or
hall sensors are being used. Do not use this wire to supply power for other devices.
Care must be taken as some optical and hall sensors are designed to use a 5V supply and
may be damaged if supplied with 8V. If a 5V supply is required then the '+5V Out' may be
used.