Quote:
Originally Posted by Brian Carlton
The light will remain on for varying time depending on the ambient temperature. However, the light and the relay are independent. I don't believe the light is on for 60 seconds on your SD. This would make no sense whatsoever because the relay drops out at approx. 35 seconds.
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I believe that if you wait for the relay to time out (loud click) and THEN crank the engine, it will be cranking with no voltage applied to the plugs. I never checked to see if the relay turns the plugs back on when you start cranking or not. The easy way around this is to let it glow until the relay clicks off, then quickly turn the key all the way off, then start cranking immediately. This would re-set the glow cycle and guarantee the plugs are on while cranking.
Note that for models with factory afterglow (all from 1990-up) the timeout is 60 seconds. The 1995-up models have up to 180 seconds of afterglow. This wouldn't apply to the OM617 or the OM603.960/961 engines in stock form.
Here's the FSM section on the afterglow function, complete with neat graphs of the time/temp relationships, etc and all the factory data:
http://www.w124performance.com/service/w124CD1/Program/Engine/602_603/15-0705.pdf
(~400kb PDF file)
