One of the supposed advantages of our diesels is that the electrical system can fail (alternator quit, battery go dead, whatever) and the engine will keep on running. As long as it's daylight, you can make it home, or so the argument goes.

As I have come to know the various Mercedes diesel models better (thanks to this forum, of course ) I realize that some of them may not run at all if the electrical system dies. For example, my wife's '96 E300D is fly-by-wire: pressing on the accelerator pedal pulls on a cable that turns a potentiometer. The potentiometer sends a signal to a computer that tells the IP to give the engine more fuel. No electricity, no signals.

If the failure is in the alternator, the battery will provide power for awhile. Using no accessories, anyone know how long the battery might last? Many hours, I would think.

The OM606 was first put in the '95 E300D and had a mechanical throttle. It should run just fine except for the idle system, which is part of the EDS "electronic diesel system" and smog equipment. I suppose the engine will run without it?

What about the W124 diesels? My '87 has EDS on its OM603 engine but is otherwise mechanical. I don't know anything about the later 300D 2.5 engines or the versions in the S-class cars.

Older cars like the W123 and older diesels should be fine. My '85 has the EDS on it but I would think it could be ignored. Will the engine stall if the EDS doesn't work to regulate the idle speed?

Anyway, I was just curious. How about the new cars, Bluetec and all that?

Jeremy

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970