Electronic Ignition (EI) System Description. Chevrolet Prizm 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Prizm 🢒 Engine 🢒 Engine Controls - 1.8L 🢒 Electronic Ignition (EI) System Description

Ignition Coils


(1)	Ignition Coil 1
(2)	Ignition Coil 2
(3)	Ignition Coil 3
(4)	Ignition Coil 4

The electronic ignition system is of the direct ignition system (DIS) type and is controlled by the powertrain control module (PCM). The electronic ignition system is composed of the following components:

•

The PCM

•	The 4 ignition coil assemblies

•	The crankshaft position (CKP) sensor

•	The camshaft position (CMP) sensor

•	The spark plugs

The electronic ignition system provides the following benefits:

•	Improved ignition timing accuracy

•	Reduced high-voltage losses

•	Enhanced overall ignition system reliability

The electronic ignition system components cannot be disassembled or repaired. A component that is correctly diagnosed as faulty must be replaced as a complete unit.

Operation

The PCM uses reference pulses from the CKP sensor in order to determine the engine speed. The PCM cannot operate the ignition system or the fuel injectors without the engine speed signal from the CKP. The PCM controls the ignition timing by controlling the ignition coils.

Each ignition coil has a built-in ignition module that controls the current flow in the primary coil winding. When the current flow is interrupted, the electrical field around the primary coil collapses and a high voltage is induced in the secondary coil. The secondary coil voltage travels from the coil output terminal, through the spark plug boot, and across the spark plug gap to the engine block. As a failsafe function the ignition control module sends an ignition confirmation signal back to the PCM whenever the primary field collapses.

The CMP sensor input is used to detect an engine misfire. The PCM also uses the CMP sensor signal as an input for modifying the fuel injection timing and for modifying the ignition timing.

The PCM receives information on the engine status from various engine sensors and then selects the most appropriate ignition timing settings from within the PCM's programming. The following are the most important inputs for determining ignition timing requirements:

•	The engine speed

•	The throttle position

•	The intake air volume

•	The engine coolant temperature

•	The knock sensor input

Noteworthy Ignition Information

Consider the following important information when servicing the ignition system:

•	The ignition coil's secondary output voltage is more than 40,000 volts. Avoid body contact with the ignition high voltage secondary components when the engine is running or personal injury may result.

•	The ignition timing is not adjustable. A timing indicator and timing marks are still visible at the crankshaft pulley but are not used to set or adjust the ignition timing. The PCM provides all ignition timing adjustments electronically.

•

Be careful not to damage the secondary ignition boots when servicing the ignition system. Rotate each ignition wire boot in order to loosen the boot from the spark plug before removing the wire. Never pierce a secondary ignition wire or boot for any testing purposes. Future ignition system problems are guaranteed if pinpoints or test lights are pushed through the secondary ignition wire insulation during component testing.

•	Do not use a conventional tachometer in order to check the engine speed on this ignition system. An inductive type pick-up will not provide reliable engine speed information. Use a scan tool in order to monitor the engine RPM.