Why a rotor on '98 4.3l GM

I have a 98 Jimmy with 4.3l v6. I noticed a rotor on this engine - why? I thought this engine had electronic ignition?
How would the ECM/PCM computer advance timing accurately if the car has a
rotor?
Mike
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It's electronic, not 100% sure how it works, but I'm sure someone here, like Ian, can pipe up and explain it...

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In article

To distribute the secondary electrical energy to the proper sparkplug/cylinder.

It does. All GM domestic vehicles have had electronic ignition since 1975, they've had ignition rotors since then also except for later model vehicles with distributorless ignition.

The rotor has little to do with ignition timing advance.
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Mike wrote in alt.autos.gm

The car still has to tell the plugs when to fire, and a rotor is one very reliable way to do so. In a non computer controlled engine a set of points opening and closing would fire the coil, and the rotor would route the spark to the proper cylinder. In the newer style, a sensor detects where the cam is, and then uses that to fire the coil. The roter just puts the spark to the proper plug. What it does is allow one coil to be used.
Other styles typically involve several coils, one for each cylinder. As far as advance goes, it can still be vacuum operated and controlled by the computer, or a solenoid could advance it. The computer also does alot more than just fire off the coil, it monitors the air and gas mixture, monitors the exhaust, and senses when there is a speed change. It also controls the air and gas mixtures, depending upon what the sensors tell it.
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