Bosch's wasted spark ignition

[Chongo]

Bosch’s Wasted spark system. How this works, is one cylinder is at a certain position BTDC, and when the ECM triggers an ignition coil to spark, current from the coil travels to one spark plug jumping the gap at the spark plug electrodes and igniting the air fuel mixture in the cylinder. The current then travels from the plug to the cylinder head to another plug ground, jumps the plug gap in reverse from the ground to the electrode back to the plug wire leading back to the shared coil pack of those 2 cylinders. This completes the circuit. The first cylinder was fired at a ECM timing BTDC and when firing through the shared cylinder of that coil, the 2nd cylinder will be on the exhaust ****** returning to the coil pack. Since the second cylinder that the current fires through is on the exhaust ****** and not compression the spark is termed “ Wasted “ because it did not create any ignition and no work resulted….. Wasted. This is why it is very important to get the plug wires back in order. This is also the primary reason for not buying gimmick spark plugs. Leave those $25.00 dollar
Gimmick plugs http://www.pulstarplug.com/ on the shelf as these plugs will not work in reverse to ground shared coil systems, ( wasted spark system).

It doesn’t matter what brand you buy, as long as the plug has the heat range that closely matches you engines requirements. If you don’t want to fool around with this Just go and buy the stock plugs for it.

Best wishes……….. Chongo

 

[Chongo]

Plug choices

Plugs chosen for the Land Rover Discovery using the The Bosch shared coil system, ( wasted spark system ), must use a plug that works both ways, and cannot be polarized or internal gimmicks placed internally that distiguish polarity of plug. These plugs must work in both directions.

Good luck.............. chongo