EWS synch problems are likely an issue for no start. Because you shouldn't be able to see the tachometer move while cranking if the EWS tamper system is active. A scan tool will be able to give you a ews synch error while cranking and that's a good first clue.
Very likely washing the engine had nothing to do with the fault occuring.
If existing key has failed, or become corrupted, you will require new keys cut and made and have a special program to read the data on the ews module and let you program new keys.
Good news is I have done this before. Bad news, it's a bit of a complex procedure to learn and follow all the steps, esp if you're not used to troubleshooting BMW's like I was at first. You will need quite a bit invested in special tools and parts to accomplish these goals unless you can outsource it to someone who has all the tooling and skills.

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2003 4.6, esotril blue, over 215,000KM. Every previous owner failed to keep up the vehicle maintenance. Restoration project.