E39 stalls after reconnecting battery

Part of the process of replacing a door cable in my 01 540 was disconnecting the battery so I did it - hesitantly. I just replaced everything, put it back together and reconnected the battery. I started it and it ran for 5 seconds and shut off. What did I do wrong?

I don't mean to sound like an idiot, but this is the of my 2 BMWs that I've done anything to. Since it doesn't have a carburetor or points, I'm lost. Help! And thanks in advance.

Hi, sounds like you have killed a fuse. The fuse can handle higher than nominal current for a short period of time while the wire in the fuse heats up from room temp to the melting point. If the overcurrent is not extremely high, the fuse survives for few seconds.

Check fuses, disconnect the newly installed cable and see if it runs.

Thanks for your reply. Left it alone for a couple of hours while doing some chores. Got it started, ran at 1,000 rpm as it should and when it warmed up, the rpm landed around 600 and was running rough. Took it out for a ride and it stalled twice. Any ideas why? Guess I should have it hooked up to look at the codes... Is there something I can buy to do it myself? Mind you my instrument cluster is highly pixelated and I cannot read any LED. Thanks

Very strange. Engine sensors and fuel pump didn't have supply voltage when you disconnected the battery so these should be o.k. DME is powered all the time, that can be damaged, but very unlikely. Alternator??

For the first step I would buy a digital multimeter and check supply voltages to see EVERYTHING is powered up and the alternator is working. Do things work connected to your new cable?

If a control module is messed up, then leave the battery disconnected for hours and see if it works afterwards.

If the power supply is o.k. then you could buy a code reader. I don't have experience with universal code readers but people here recommend the Peake tool.

You might need to re-Adobt the throttle body

My car used to die after leaving the battery off too long. The problem you face is if the battery is off long enough to reset your clock its off long enough to clear all dme adaptation values. The car defaults to the baseline nonadjusted values which apparently your car does not like. This means you either A have some issues such as vac leaks that the car is noncompensating for or B have nonstock performance parts. In my case i believe the car did not like m60 intake manifold and would stall. After driving a few miles the car will relearn what adaptations it will need to make to run better. I bought the ESS tuning m60 manifold tune nd my car runs fine now after having the better disconnected because the baseline values are changed to accomodate my aftermarket engine configuration.

The bottom line is that if your car is stock, you may have some maintainence/repair work ahead of you. If your car was in perfect order it would not stall with the baseline values.