Electronic Ignition EI (High Data Rate)

1 .9L SF1 EI (High Data Rate) System and Component Description

System Description

The 1 .9L SFI Electronic Ignition (High Data Rate) System consists of a Crankshaft Position (variable-reluctance) Sensor (CKP) an Ignition Control Module (ICM) a Powertrain Control Module (PCM) and one 4-Tower Coil Pack.

The Electronic Ignition (High Data Rate) System operates by sending crankshafi position information from the CKP sensor to the ICM. The module generates a PIP signal and sends it to the PCM. The PCM responds with a SPOUT signal containing advance or retard timing information back to the ICM. The module processes the CKP and SPOUT signals and decides which coils to fire. In addition the module generates an Ignition Diagnostic Monitor (IDM) signal to the PCM which is used to indicate a failure mode and also provide a tach output signal.

Component Description

CKP Sensor

The CKP sensor is a passive electromagnetic device which senses movement of a 36 minus one-tooth wheel located behind the crankshaft pulley. An A/C voltage signal is generated which increases with engine rpm and provides engine speed and crankshafi position information to the PCM.






Component Description

Ignition Control Module (ICM)

The ICM is a microprocessor-based device with coil drivers which make decisions about spark timing and coil firing. The module turns the coils on and off at the correct time and in the proper sequence based on information from the CKP sensor and a pulse-width modulated signal (SPOUT) generated from the PCM. The module receives CKP and SPOUT signals and produces PIP and IDM output signals which are sent to the PCM.






Powertrain Control Module (PCM)

The PCM receives IGN GND and PIP signals from the ICM then generates a SPOUT output signal based upon engine speed load temperature and other sensor information. An IDM signal is received from the ICM to determine if an ignition failure mode should be recorded.






Component Description

Coil Pack

The coil is turned on (coil charging) by the ICM then turned off, firing two spark plugs at once. One is for the cylinder which is to be fired (on compression stroke) and the other goes to the mating cylinder which is on the exhaust stroke. The next time the coil is fired the situation is reversed. The next pair of spark plugs will fire according to the engine firing order etc.






Repetitive Spark

Repetitive Spark is used to improve idle stability. It is enabled by the PCM program below 1000 rpm. If in the repetitive spark mode afier the first spark is sent to a pair of spark plugs the plugs will be re-struck up to three more times very quickly. The repetitive spark primary waveform can be seen using a engine analyzer with EI capability.

Note:The required tachometer adapter (Rotunda 007-00061) is compatible with all Ford EI vehicles and is also compatible with the repetitive spark mode. A standard tachometer may not be compatible with this vehicle.