Ignition Coil; Mfi Relay (Automatic Shut Down) - Mitsubishi Eclipse Technical Information Manual

IGNITION COIL

The coil assembly consists of 2 coils molded togeth-
head cover. High tension leads route to each cylinder
from the coil. The coil fires two spark plugs every
power stroke. One plug is the cylinder under com-
pression, the other cylinder fires on the exhaust
stroke. Coil number one fires cylinders 1 and 4.
Coil number two fires cylinders 2 and 3. The power-
train control module (PCM) determines which of
the coils to charge and fire at the correct time.

MFI RELAY (Automatic Shut Down)

The MFI relay (automatic shut down relay) supplies
battery voltage to the fuel injectors, electronic igni-
tion coil, generator, and the heating elements in
the oxygen sensors.
The PCM controls the relay by switching the ground
path for the solenoid side of the relay on and off.
The PCM turns the ground path off when the ignition
switch is in the Off position. When the ignition switch
is in the On or Crank position, the PCM monitors
MFI relay 1
The MFI relay (automatic shut down relay) provides
battery voltage to the ignition coil. The PCM provides
a ground contact (circuit) for energizing the coil.
When the PCM breaks the contact, the energy in
the coil primary transfers to the secondary causing
the spark. The PCM will de-energize the MFI relay
if it does not receive the crankshaft position sensor
and camshaft position sensor inputs. Refer to MFI
Relay PCM Output in this section for relay operation.
the crankshaft position sensor and camshaft position
sensor signals to determine engine speed and igni-
tion timing (coil dwell). If the PCM does not receive
the crankshaft position sensor and camshaft position
sensor signals when the ignition switch is in the
Run position, it will de-energize the MFI relay.
Along with the fuel pump relay, the MFI relay at-
taches to a bracket on the drivers side of the dash
panel.
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