19587 1 Mercury PLATE, MOUNTING

Illustration 1 g00826129
(1) Shutoff solenoid (2) Rack position sensor (3) Engine Data Link connector (4) Rack solenoid (5) Engine speed sensor (6) Transducer module (7) ECM (8) Ground stud on the engine block (9) Coolant temperature sensor (10) Timing solenoid (11) Timing position sensor (12) Vehicle speed sensor (13) Vehicle speed buffer (14) Dash Data Link (15) Throttle position sensor (16) Negative ground through starter or main frame rail (17) Coolant level sensor (18) Diagnostic lamp (19) Warning lamp (20) Clutch switch (21) Brake switch (22) Parking brake switch (23) Cruise control ON/OFF switch (24) Cruise control SET/RESUME switch (25) Battery (26) OEM vehicle wiring harnessThe Programmable Electronic Engine Control (PEEC III) uses several electronic input components. These components require an operating voltage. Sometimes, the components require a reference voltage as well. Refer to Electrical Schematics, SENR5509 for the electrical schematics of the PEEC III system.Grounding Practices
Proper grounding for the vehicle and the engine electrical systems is necessary for proper vehicle performance and reliability. Improper grounding will result in uncontrolled electrical circuit paths and unreliable electrical circuit paths. Uncontrolled engine electrical circuit paths can result in damage to the following components:
main bearings
crankshaft bearing journal surfaces
aluminum componentsUncontrolled electrical circuit paths can cause electrical noise which may degrade the vehicle and the radio performance. To ensure the proper functioning of the vehicle and engine electrical systems, an engine-to-frame ground strap with a direct path to the battery must be used. The direct path to the battery can be accomplished by the following methods.
starter motor ground
frame to starter motor ground
direct frame to engine groundIn any case, an engine-to-frame ground strap must be run from the cylinder head grounding stud to the frame and the negative battery post.
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Cylinder head to battery ground (1) Cylinder head ground stud (2) Frame (3) Battery
Illustration 3 g00536186
Alternate cylinder head to battery ground (1) Cylinder head ground stud (2) Negative terminal on starter (3) Frame (4) BatteryThe cylinder head must have a wire that is grounded to the battery. Refer to the above illustrations. Ground wires or ground straps should be combined at ground studs that are dedicated for ground use only. The engine grounds should be inspected after every 20125 km (12500 miles) or every 250 hours. All grounds should be tight and free of corrosion. All ground paths must be capable of carrying any likely fault currents. An AWG # 0 or larger wire is recommended for the cylinder head grounding strap. The alternator should be battery ground with a wire size that is capable of managing the full charging current of the alternator.
When boost starting an engine, follow the instructions in the Operation and Maintenance Manual.
The engine has several input components which are electronic. These components require an operating voltage. Unlike many electronic systems of the past, this engine is tolerant to common external sources of electrical noise. Electro-mechanical buzzers can cause disruptions in the power supply. If electro-mechanical buzzers are used anywhere on the vehicle, the engine electronics should be powered directly from the battery system through a dedicated relay. The engine electronics should not be powered through a common power bus with other key switch activated devices.Electronic Control Module Power Circuit
The design of the electronic circuits inside the Electronic Control Module (ECM) allows the ordinary switch input circuits to the ECM to have the following characteristics:
tolerance for resistance between the wires
tolerance for shorts between wires
The 12 Volt wire in the data link harness of the ECM is provided to power the PEEC III service tools only. No other devices should be powered by the wire. The ECM was not designed to carry high current loads and is not short circuit protected.
The ECM draws a maximum of 7.5 Amp at 12 Volts from the electrical system of the vehicle. However, PEEC III will function with less than 12 Volts. When the engine is being cranked, the ECM requires a minimum of 6 Volts. When the engine is running, the ECM requires 9 Volts. Power enters the ECM through the positive battery wire and exits through the negative battery wire. Negative battery must be within .5 Volt of the vehicle frame ground. The PEEC III system is protected against power surges on the 12 Volt power supply. The surges are due to the following conditions:
alternator load dumps
air conditioner clutches
jump starting
other conditionsEngine Speed Input Circuit
Engine speed is sensed by an engine speed sensor. The sensor is similar to other electromagnetic pickups. The signal is generated by placing the sensor near a rotating component, but the sensor requires an operating voltage. The ECM provides the engine speed sensor with an operating voltage of 8.0 0.4 Volts.The output of the engine speed sensor is a voltage pulse. The pulse's frequency is dependent on the speed of the engine. The frequency of the pulse is interpreted by the ECM as engine speed. The signal's frequency is 10 to 50 Hz when the engine is being cranked. The signal's frequency is approximately 120 Hz at low idle. Fuel Rack Input Circuit
The engine fuel rack signal is obtained from an electronic linear position sensor which follows the movement of the rack assembly. This sensor requires an operating voltage of 8.0 .4 Volts, and a reference voltage of 5.00 .25 Volts. These voltages are provided by the ECM. The output of the Rack Position Sensor is a voltage between .3 and 5.25 Volts. This voltage is dependent upon the