Fact... or old wives' tale!

[Scamp's Walker]

Hi

Suffered a completely flat battery on my '98 E39 having not driven the car for two weeks, not sure why so will have to investigate, so jump started it from another car. Clock had completely stopped and had to reset that plus the date etc. Will the completely discharged battery have affected anything ie computer data, engine/auto gearbox settings etc? Having jump started it spoke to a long time BMW owner who suggested that he understood that jump starting the car was the worst thing I could have done as it could have caused a power surge, which would have been detrimental tomthe electronics, and that I should have taken the battery out and trickle charged it? Any, views, opinions or advice welcomed. I am guessing that if i had called the AA/RAC they would probably have jump started it anyway!

[lance1a]

There's a method of jump starting newer model cars, not just BM's, (which is detailed in the handbook) though I have had (and still have) many BMW's and not one with a problem that arose from dodgy jump starting. I do try to make a point of running the demister on any car I jump though, just as a precaution.

[belleair302]

Fiction!

[agent006]

In theory it can be a problem. '80s Audi Quattros are particularly prone to problems with jump starting frying the dashboard electronics. So long as you jump start it as per hte process in the manual it'll be fine. Usually involves th enegative lead going in a particular place.

[Neil.D]

the only thing it will do to the engine is reset the ECU. Unless you drove it hard all the time then they tend to adjust to your driving style.
The car amy feel a little more responsive when you nest drive it. Always a good thing.