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B6304 Motronic 1.8 What EXACTLY does the Ign, Power Stage Do? 900 1995

The Power Stages(2) on the B6304 control the ignition, but how exactly?

The ECM takes in sensor data and grounds the - signal wire for each cylinder (coil) thru both Power Stages.

+ Power is supplied to the coils through the Green/Red wire to each coil.

The Signal wires for 3 of the cylinders goes to each P.S., where 3 wires (plus a black ground wire) come out and go to the ECM.

If the ECM is controlling timing. What is the purpose of the Power Stage? All - singal wires from the ECM go through a Power Stage before hitting the coils. They're some sort of intermediary. Nothing in the Volvo manuals describes this, and neither does my Bosch Motronic book either.

All I can think of is that it energizes the coil(s) by supplying signal/voltage for a certain duration. Just a SWAG on my part. Please enlighten me.

Your thoughts are appreciated.

DEWFPO
--
1998 S90 071,245 and 1995 964 154,100






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New B6304 Motronic 1.8 What EXACTLY does the Ign, Power Stage Do? [900][1995]
posted by  dewfpo  on Wed Feb 2 09:22 CST 2005 >


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