Morse timing chain (some early production engines had double-row roller timing sets), which was located beneath the aluminum timing cover at the front of the engine block. The timing chain sprockets, one each for the camshaft and crankshaft, were all-steel; for the last few years the LA engine came with nylon teeth on the sprockets. At the rear of the camshaft was cut a set of helical gear teeth, these being used to spin the distributor. Mounted to the front of the timing cover was a new-design counter-clockwise-rotation water pump, with much improved flow. Externally, the accessory drive belt was changed to a serpentine system; coupled with an automatic belt tensioner this increased belt life, reduced maintenance and contributed to lower noise and vibration levels. The ignition system was also all-new for the Magnum. Controlled by a new micro-processor-equipped Single-Board Engine Controller (SBEC, also known as the ECM, or Engine Control Module), the ignition system included a distributor mounted at the rear of the engine. A 36,000-volt ignition coil, usually located at the front right of the engine, provided electrical power to the center of the distributor cap, where a spinning rotor directed the power to each of the individual cylinders' spark plug wires. Ignition dwell, advance and retardation were electronically controlled by the SBEC. The SBEC controlled the ignition, as well as the opening and closing of the fuel injectors. During cold startup, wide-open throttle and deceleration, it did this based on "open-loop", pre-programmed operating parameters. During normal idle and cruising, it began "closed-loop" operation, during which the module acted based upon inputs from a variety of sensors. The basic sensors that provided input to the SBEC included the Oxygen sensor (O2), Manifold Absolute Pressure (MAP) sensor, Throttle Position Sensor (TPS), Intake Air Temperature (IAT) sensor and Coolant Temperature sensor (CTS). The basic actuators controlled by the SBEC's outputs included the fuel injectors, ignition coil and pickup, and the Idle Air Control (IAC) valve. The latter controlled idle characteristics. However, the SBEC also controlled the operation of the charging system, air conditioning system, cruise control and, in some vehicles, transmission shifting. By centralizing control of these systems, the operation of the vehicle was simplified and streamlined. Emissions output was controlled by several systems. The EGR, or Exhaust Gas Recirculation system, brought exhaust gas from the exhaust stream up to the intake manifold, lowering peak combustion temperatures, the goal being