Distributorless Ignition System; General Information; System Operation - Ford Ranger Maintaince And Repair Manual

DISTRIBUTORLESS IGNITION SYSTEM

General Information

The distributorless ignition system used by 1991−94 2.3L and 4.0L, and all 1995−99 engines is referred to as
the Electronic Ignition (EI) system. It eliminates the conventional distributor by utilizing multiple ignition
coils instead. The EI system consists of the following components:
• Crankshaft Position (CKP) sensor
• Ignition Control Module (ICM) (EEC−IV systems only)
• Ignition coil(s)
• The spark angle portion of the Powertrain Control Module (PCM)
• Related wiring
The function of the ICM was incorporated into the PCM beginning with the EEC−V system; otherwise
the newer system operates in the same manner.

SYSTEM OPERATION

The CKP sensor is a variable reluctance sensor, mounted near the crankshaft damper and pulley.
The crankshaft damper has a 36 minus 1 tooth wheel (data wheel) mounted on it. When this wheel rotates the
magnetic field (reluctance) of the CKP sensor changes in relationship with the passing of the teeth on the data
wheel. This change in the magnetic field is called the CKP signal.
The base ignition timing is set at 10 (plus or minus 2 degrees) degrees Before Top Dead Center (BTDC)
and is not adjustable.
EEC−IV Systems
The CKP signal is sent to the ICM, where it is used to create the Profile Ignition Pick−up (PIP) signal.
The one missing tooth on the data wheel creates one large space between two of the teeth. The ICM utilizes
this large space as a reference to help determine base ignition timing and engine speed (rpm), and to
synchronize the ignition coils for the proper spark timing sequence.
DISTRIBUTORLESS IGNITION SYSTEM 185