iridium spark plugs and the waste spark

[Toyota18]

Hi.
2001 Toyota Camry 5sfe engine (with out a ignition distributor)only recommending the twin ground spark plugs,Is this some thing to do with the waste spark ignition?
GM 3.8L V6 also use the waste spark ignition but with single gorund spark plugs.Why toyota only recommending twin ground plugs in camry 5sfe engine?
Thanks.

 

[Greaser]

Couldn't tell you why Yota would specify only those plugs

My Jeep 4.0L engine has the second spark on the exhaust stroke also and I've been using Champion Gold Truck plugs with excellent results thus far...why is there a dual spark anyways???

 

[Gary Allan]

quote:

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why is there a dual spark anyways???

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If I interpret your question correctly...
Simplicity mainly. You have two plugs per jug. One trigger for each coil. You just route your plug wires to the corresponding cylinder thats on the exhaust stroke when you're BTDC on the compression stroke of another. You get the equivalent of nearly 360° of dwell time divided between the two. I imagine you wouldn't get anything much in the way of reduced emissions from the spark in the spent cylinder ..but some might assert that you do ..and they may be correct

The alternative is one plug per jug and the PCM has to generate 6 (or 8 ..whatever) pulses. In the jeep it gets 3 triggers from the Crank position sensor on the flywheel. Three notches that the sensor detects. Fuel injection triggering is handled, oddly enough, by the cam position sensor that is where the distributor used to be in your 4.0.

and moving this to Auto & Gen.