Jump started E32 730i, then burned a fuse?

[DeBum]

Hellow everyone,

I own a 7.30i (the E32 model, 1986 i belive) and recently i tried to start it,
for the first time in about a year.

Naturally the battery was dead so i tried jump starting it (on a 12v diesel powerd fork-lift).
With the Jump cables correctly connected i turned the key one step and it looked like the car got to much elec. power.
All the dashboard lights where really (to) bright, and i heard a buzzing sound, that told me, allricht it must have got LOTS of electricity now.

Then turned the key all the way and the engine turned around once or twice, really slowly. I stopped for 10 sec.
Then fully turend the key again and heard the starter engine trying for 0,5 sec and then all of a sudden, all the. power was gone! Not one dash light nothing, no power at all!

So it must be a fuse or a relay or someting i guess ?? does anyone maybe know witch one i clould be?

Or where i can find information on this (but not my bmw dealer plz, he will just rip me off)

Thanks and sorry for my crappy english

[philakamrbean]

A problem I have dealt with on older 124 Chassis Mercedes cars is an overload protection relay with a 15?amp fuse in it. Too much juice from a jumpstart would kill the fuse and relay. I have no idea if BMW uses such a contraption, but its worth a look.

Otherwise, grab a test lite and start checking the various fuses. Perhaps something under Ignition?

[philakamrbean]

....are you sure that forklift was only 12volt? When you try to run 24volts through a 12 volt light, it gets really really reallly bright.

[blkonblk540i]

....are you sure that forklift was only 12volt? When you try to run 24volts through a 12 volt light, it gets really really reallly bright.

busted

[bmwdirtracer]

My thought exactly. How many batteries does the forklift have, and are they wired in series, or in parallel? How many caps does each battery have?

[DeBum]

no really it was a 12V forklift, tested it with a Volt meter

going to change te relays tomorrow

[bmwdirtracer]

I'd check the main battery wires, at both ends, and, if the battery's in the trunk, check the B + terminal at the engine compartment. Then, I might suspect the ignition switch, or the main relay.

[shogun]

This is an old thread, but as you posted in the forum today about another problem on your 730, your car is still running.
What was the problem then in 2008? How did you fix this problem? Have you checked the 2 fusible links? http://www.bimmerboard.com/forums/posts/377728/