Basically, on the rear of the IP there is a module which has a port to attach a vaccum line. When vaccum is applied to that line it cuts off the fuel and shuts down the engine. If I understand correctly, the factory 190D applies this vaccum via the ignition switch. A switchover valve can be plumbed in as an alternative as it opens when power is removed.

Is there no difference between a diesel auto trans and a gasser?

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