Check crankshaft position sensor.?
IGNITION SYSTEM OPERATION
This ignition system does not use a conventional distributor and coil. It uses a crankshaft position sensor input to the powertrain control module (PCM)/engine control module (ECM). The PCM/ECM then determines Electronic Spark Timing (EST) and triggers the electronic ignition system ignition coil.
This type of distributorless ignition system uses a "waste spark" method of spark distribution. Each cylinder is paired with the cylinder that is opposite it (1-4 or 2-3). The spark occurs simultaneously in the cylinder coming up on the compression stroke and in the cylinder coming up on the exhaust stroke. The cylinder on the exhaust stroke requires very little of the available energy to fire the spark plug. The remaining energy is available to the spark plug in the cylinder on the compression stroke.
These systems use the EST signal from the PCM/ECM to control the electronic spark timing. The PCM/ECM uses the following information:
Engine load (manifold pressure or vacuum).
Atmospheric (barometric) pressure.
Intake air temperature.
Engine speed (rpm).
The Electronic Ignition (El) system ignition coil is mounted near the rear of the camshaft carrier on the single overhead camshaft engine. On the dual overhead camshaft engine, the El system ignition coil is mounted near the rear of the cylinder head. Each pair of terminals of the El system ignition coil provides the spark for two spark plugs simultaneously. The El system ignition coil is not serviceable and must be replaced as an assembly.
CRANKSHAFT POSITION SENSOR
This electronic ignition system uses a magnetic crankshaft position sensor mounted just ahead of the block below the intake manifold. This sensor protrudes through its mount to within approximately 1.3 mm (0.05 inch) of the crankshaft reluctor. The reluctor is a special wheel attached to the crankshaft pulley with 58 slots machined into it, 57 of which are equally spaced in 6 degree intervals. The last slot is wider and serves to generate a "sync pulse." As the crankshaft rotates, the slots in the reluctor change the magnetic field of the sensor, creating an induced voltage pulse. The longer pulse of the 58th slot identifies a specific orientation of the crank shaft and allows the powertrain control module (PCM)/engine control module (ECM) to determine the crankshaft orientation at all times. The PCM/ECM uses this information to generate timed ignition and injection pulses that it sends to the ignition coils and to the fuel injectors.
CAMSHAFT POSITION SENSOR
The Camshaft Position (CMP) sensor sends a CMP sensor signal to powertrain control module (PCM)/engine control module (ECM). The PCM/ECM uses this signal as a "sync pulse" to trigger injectors in proper sequence. The PCM/ECM uses CMP sensor signal to indicate position of #1 piston during its power stroke. This allows PCM/ECM to calculate true sequential fuel injection mode of operation. If PCM/ECM detects an incorrect CMP sensor signal while engine is running, DTC P0341 will set. If CMP sensor signal is lost while engine is running, fuel injection system will shift to a calculated sequential fuel injection mode based on last fuel injection pulse, and engine will continue to run. As long as fault is present, engine can be restarted. It will run in calculated sequential mode with a 1-in-6 chance of injector sequence being correct.
Friday, December 19th, 2008 AT 8:28 AM