Brian, I thought I remembered in my OM603 (1986 SDL) that the GPs stay energized with the key turned to position III and remain on during cranking, only shutting off after the key is back to postion II (run) to allow the GPs to continue to assist during cranking.

I also remember the Owner's Manual being specific about starting in one continuous 'cranking' and not using short cycles like a gasser, to allow this continued glow to assist during cranking.

That said, I also remember that on some models the GPs continue to glow for a given time even after the key returns to postion II (after-glow and 'violet wire' subjects) to allow smoother warmup and emissions control.

Of course, I''' bet that there are a lot of model-specific variations...