Long crank diesel e53 is almost always the starter.

I've seen at least a dozen threads, only maybe two weren't the starter.

Get an amp reading at start and see what the current is: I think it's supposed to be about 250A. I've seen over 400!

Usually people first replace the battery and it will start much faster they think they resolved the problem until the starter pulling 50-100% more current is killing the battery.

If not the starter it will be a good data point to consider options.

I haven't worked on diesels or done any work on high pressure fuel pumps yet (though both mine and wife's cars both have them (gas not diesel). The hpfp is very pricy, hope it's not that.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)