For 1990-2009 cars

### Electronic Ignition (EI)

The Electronic Ignition (EI) system on the 3400 LA1 (VIN E) engine uses a coil pack with one ignition coil for each two cylinders in the engine. Mounted under the ignition coils on each system is an Ignition Control Module (ICM) that performs ignition coil switching functions and interacts with the Powertrain Control Module (PCM) to optimize ignition system operation. On these engine systems, the spark timing is controlled electronically. The ICM controls the spark timing during engine start-up, and provides a back-up timing system that will allow the engine to run in the event of an open or ground in the Ignition Control (IC) circuit. Once the engine starts and is running above an approximate engine speed of 400 RPM, the PCM takes over the spark timing and sends signals to the ICM for ignition coil switching. The electronic ignition systems used on these engines use a waste spark method of spark distribution. Each cylinder is paired with its opposing cylinder in the firing order, so that one cylinder on compression fires simultaneously with the opposing cylinder on exhaust. The spark that occurs in the cylinder that is on the exhaust stroke is referred to as the waste spark. The spark plugs in the two opposing cylinders are connected to the two secondary terminals of the same ignition coil. The spark voltage appears at the center electrode of one of the spark plugs and jumps to the side electrode, then passes through the engine to the other spark plug. At the second spark plug, the spark jumps from the side electrode to the center electrode and completes the series circuit back to the ignition coil. The high level of energy available from the ignition coil is more than sufficient to fire both plugs simultaneously. Since the waste spark requires very little of the available voltage to fire, most of the coil output voltage is available to fire the cylinder that is on the compression stroke. Engine speed (RPM) and cylinder position in the intake-compression-power-exhaust sequence are sensed electronically and are used by the ICM and PCM to control timing. These parameters are provided by a magnetic Crankshaft Position (CKP) sensor mounted in the engine block. The magnetic CKP sensor consists of a wire coil wound around a permanent magnet. The sensor is positioned near a reluctor ring on the crankshaft. The reluctor ring has notches which trigger signals in the magnetic sensor to indicate Crankshaft Position (CKP) and crankshaft speed (RPM). These signals are used by the ICM during start up, then passed on to the PCM to help determine optimum timing while the engine is running. The PCM also uses other inputs separate from the ignition system itself, to determine optimum timing.

### Secondary Ignition Wiring

The spark plug wiring used with ignition systems is a carbon impregnated cord conductor, encased in a 7 mm (9/32 in) or 8 mm (5/16 in) diameter silicone rubber jacket. The silicone jacket withstands very high temperatures. Silicone spark plug boots form a tight seal on the plug. The boot should be twisted 1/2 turn before removing. Care should also be used when connecting a timing light or other pick-up equipment. Do not force anything between the boot and wiring, or through the silicone jacket. Connections should be made in parallel using an adapter. Do not pull on the wire to remove. Pull on the boot, or use a tool designed for this purpose.

### Spark Plugs

#### Extended Life Spark Plug (Typical)

(1) | Spark Plug Identification Number Location
(2) | Copper Core Centerwire
(3) | Platinum
(4) | Nickel Plated Shell

Resistor type, tapered seat spark plugs are used on all engines. No gasket is used on these tapered seat plugs. When replacing spark plugs, use only the type specified. Normal service is assumed to be a mixture of idling, slow speed, and high-speed driving. Occasional intermittent high-speed driving is needed for good spark plug performance. Intermittent high-speed driving gives increased combustion heat, burning away carbon or oxides that have built up from frequent idling, or continual stop-and-go driving. Spark plugs are protected by insulating boots made of special heat-resistant materials, which cover the spark plug terminal and extend downward over a portion of the plug insulator. These boots prevent flash-over, which causes engine misfiring. Do not mistake corona discharge for flash-over, or a shorted insulator. Corona is a steady blue light appearing around the insulator, just above the shell crimp. It is the visible evidence of a high-tension field and has no effect on ignition performance. Usually it can be detected only in darkness. This discharge may repel dust particles, leaving a clear ring on the insulator just above the shell. This ring is sometimes mistakenly regarded as evidence that combustion gases have blown out between the shell and the insulator.

### Ignition Switch

The mechanical key and lock cylinder switch is located in the steering column on the right-hand side, just below the steering wheel. The electrical switching portion of the assembly is separate from the key and lock cylinder.