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G'Day Cliff,
You can't have looked very hard, see the link in my sig and download the Alfa 75, Twin Spark 'S' manual and look in group 00 (page 71 75TS_S-00-71.gif).
Cliff and Sam,
Below is a description of what the ECU does when you turn the key, read it in conjunction with the diagram.
The four relays on the firewall are (from left to right, This may be
different on your car).
S12a Fuel Pump
S12b Motronic
S12c VVT
S12d Aux Motronic
Turning on the ignition switch (to run or start) provides power to S12a
(Fuel Pump Relay) switched contacts (but does not turn S12a on) and turns on
S12d (Aux Motronic Relay).
S12d (Aux Motronic Relay) provides power to the ignition coils, power to
S12c (VVT Relay) (but does not turn S12c on) and turns on S12b (Motronic
Relay).
S12b (Motronic Relay) provides power to S12a (Fuel Pump Relay) coil (but
does not turn S12a on), provides power to pin 35 of the ECU, provides power
to the Idle Actuator (but does not turn it on) and provides power to the
injectors (but does not turn them on).
NOTE! S12b must have a diode inside it or in the Green/Black wire going to
it.
When the ECU detects the engine is turning (via the CrankAngleSensor) it
turns on S12a (Fuel Pump Relay).
The ECU now controls the Ignition Coils, the Fuel Pumps (both together), the
VVT, the Idle Actuator and the Injectors.
Hope this helps,
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