Ignition System - Solid State - Ford VSG-411 Service Manual

2A-01 Ignition System
2A-01
PART 2A - Ignition System - Solid State
COMPONENT INDEX
Page COMPONENT INDEX (CONT' D.) Page
IDENTIFICATION ................... 2A-01 CLEANING AND INSPECTION ....... 2A-06
DESCRIPTION ..................... 2A-01 Spark Plugs ......................
2A-06
DIAGNOSIS AND TESTING ......... 2A-02 Distributor
........................ 2A-06
ADJUSTMENTS .................... 2A-04
Distributor Cap and Rotor .......... 2A-06
REMOVAL AND INSTALLATION
..... 2A-05 Ignition Wires ..................... 2A-06
Distributor ........................ 2A-05 Ignition Coil
...................... 2A-06
Spark Plugs ......................
2A-05
Vacuum Diaphragm ...............
2A-05
IDENTIFICATION
PART NUMBER
The distributor identification number is stamped on the distrib-
utor housing. The basic part number for distributors is 12100. To
procure replacement parts, it is necessary to know the part number
prefix and suffix (Figure 1).
Always refer to the Parts Catalog for parts usage and inter-
changeability before replacing a distributor or a component part
for a distributor.
prgyj
t
FIG.
1
Distributor identification
DESCRIPTION
The solid state ignition is the breakerless type. The distributor is
located on the right side of the engine. It is equipped with a
vacuum and a centrifugal advance unit to control ignition timing.
It has a stator and trigger wheel that sends a signal to the TFT
electronic amplifier module which is located on the distributor
housing. The module switches the primary circuit, in the coil, on
and off controlling the secondary current to the spark plugs.
Notice that the primary circuit to the coil (Fig. 2) does not have
a ballast resistor. The coil is supplied with battery voltage at all
times. The module is energized by a circuit from the ignition
switch.
When the trigger wheel arms are between the stator pick-up
arms, the module will switch on. This allows current to flow from
FIG. 2
the battery, through the ignition switch to the primary winding of
the coil. From the coil the current flows through the module
circuits to ground through the distributor body.
When a trigger wheel arm is directly opposite a stator arm (Fig.
3), the voltage induced in the trigger coil will change from a
positive to a negative voltage. This change over will trigger a
circuit in the module, which switches OFF the ignition coil prima-
ry circuit. This results in the collapse of the ignition coil magnetic
field which generates the high voltage required to fire the plugs.
The solid state ignition system uses a high output coil. It can be
identified by the safety cover on the top. The cover would allow
the coil to fail safely in the unlikely event of a module malfunction
in which coil current is left on permanently.
IGNITION
SWITCH
FIG. 3