1998 BMW 540i 6 Speed ignition cylinder/tumbler

[SgtPete 0311]

Bought a 98 540i with an aftermarket redneck ignition. To start I have to put key through the round antenna(?) and then use a long file to start her up. So I’m looking for a ignition cylinder/tumbler

[R Shaffner]

I think one if the main reasons this forum is so helpful is because BMW often makes things complicated. In this case, because the BMW key for that car uses 2 different security processes, the wrong ignition cylinder/tumbler probably won't help.

On the other thread we talked about the antenna in the black ring around the key hole. BMW designed the system so the key that turns the cylinder would also be close enough to the antenna for the old key and the EWS to make the secret wireless handshake when the key is turned. If you got a used cylinder and another key from someone, it wouldn't be able to do the handshake. So the engine wouldn't start, unless you were somehow able to hold your current key next to the new one so it would do the wireless part while the new key turned the tumbler.

And of course some other used key wouldn't work in your door locks.

That's why JimLev suggested that you get a cylinder/tumbler from a dealer to match your car and key. It's the best way to have one key that starts the car, does the locks, etc.

(I think another way would be to have the car's EWS deactivated and DME re-coded, but that's harder and presents other issues. And then you'd still need a key for the ignition and another key for the doors.)