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1998 E36 M3 convertible - after the battery is re-connected

I am planning to do some work on the car, (replace speaker, adjust conv top, replace microfilter), before which, everywhere I read, it seems advisable to disconnect the battery.

After re-connecting the battery, a friend with another M3 said the engine did not run very well, but got better after a good drive through all gears, all speeds etc. has anyone had a similar experience? Sounds like the engine management system does not like to be without power.

I have the original radio code card, inc. the serial number, so no worries there. Other than the radio code, what other electrics need attention after re-connecting the battery?

Ta

Reply to
mcquarrie
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Doesn't look like you're doing anything that actually needs the battery disconnected. Unless working near the battery where there is a chance of shorting the terminals (through dropped tools, etc) or on anything not protected by fuses.

Dunno about the M3. It might have gone back to a low octane petrol default, but should have changed back pretty quickly.

On my 528 of a similar age, nothing. Not even the radio code as it doesn't have one. Just had to re-set the clock and radio station memory.

Reply to
Dave Plowman (News)

Perhaps - but I see nothing you've mentioned that I would disconnect the battery for.

I think your friend was imagining things. On later models the "adaptation memory" is not volatile.. to reset it you have to use a code reader capable of reading BMW codes.

You'll have to reset the OBC-MID - clock, speed reminders, whatever..

Reply to
Don

Thanks. What is "OBC-MID"?

Reply to
mcquarrie

BTW the Bentley service manual does recommend disconnecting the battery before working on anything near airbags (in my case, glovebox, door speaker). That is what I plan on doing.

Also, it's never a bad idea to disconnect the battery when working near electrical wiring - cutting a live wire can cause a short. Best case blown fuse, worst case small fire, either case best avoided.

Safety first.

Reply to
mcquarrie

Well, you have the windows to re-initialize, but this is a matter of running them to the top while holding the button the whole way. Then, there's the radio, but you have that covered. As for the ECU, it resets itself very quickly just by going for a short drive. I've never experienced a problem with the ECU after disconnecting the battery, but I've heard the complaint before. It's a non-issue. Oh, you have to reset the clock.

Reply to
Jeff Strickland

The microfilter is pretty close to the airbag, and the book recommends disconnecting the battery to prevent the airbag from going off in your face.

Reply to
Jeff Strickland

Thank you Jeff.

Reply to
mcquarrie

The microfilter is below and behind the dashboard and behind the heater.. The airbag is above the glovebox. If you could set off the airbag while replacing the microfilter you're a magician.

Reply to
Don

On-Board-Computer, Multi-Instrument-Display. The thing below your heater controls.. where the clock lives.

Reply to
Don

Well, the glove box is immediately below the airbag, and is in the way of other stuff that has to come out/off to get to the filter. So, tripping the airbag doesn't take a magician, it only takes a bafoon. And since the factory doesn't know if you're a bafoon or not, then everybody is recommended to disconnect the battery.

Reply to
Jeff Strickland

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