P E H, in a few previous postings you stated that you had engines where it didn’t seem to matter if a couple of glow plugs worked or not – the engine still started. And for the same engines if one plug went then the engine wouldn’t start. And it seemed to be the same cylinders that acted the same way. Swap plug from one of the cylinders that didn’t matter and off you went. Now let’s say the crank stops close to the same place when you shut the car off. In the short term it should, as long as you shut down the same way – heat/AC off, radio off, same gear, low idle selected, etc.- due to cylinder compression ratio imbalance and different clearances in main bearings, wrist pins, etc. If this is really true then a particular cylinder should be set up for a compression stroke the next time you start the car, and just about every time you start the car. Glow, fire the starter, the crank compresses that cylinder and the cylinder fires. This is the cylinder where the glow plug matters. Now let’s say that the crank sets up another cylinder for a power stroke. Glow, fire the starter, the crank expands the cylinder then exhausts then intakes then compresses. That cylinder isn’t going to fire as easily as the cylinder that was set up for a compression stroke. All this on a cold engine. And all a moot point in a series system. And a moot point if you keep the fuel clean and dry.

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daBenz - 1970 220D