97 1.9 Z3 Cranks, but no start

[mrscalex]

I would say yes it needs syncing, some of the info contained in the EWS, and DME is also stored in the light switch unit, its held there as a backup should the other two modules fail. As far as I am aware once the EWS and DME are synced the light unit takes the update as well. Nothing to loose in doing the sync using INPA to see if that gives you back the sparks to start.
I do note that you have an early car with EWS2 it should be ok using INPA but often early cars need a real serial port on the laptop in order to communiicate they dont like a usb connection on the laptop same for some of the handheld scanners.
Disconnecting the battery will not reset any codes.

The headlight control unit only holds the data on 3 Series. Not on Z3s. Common thought to get passed round from BMW tech docs not written specifically for Z3s.

 

[colb]

I coded an airbag module to a Z3 and used the cars data held in the EWS to code it to the car using NCS Expert thought the data was also held in the lighting switch unit, happy to be corrected.

 

[mrscalex]

I coded an airbag module to a Z3 and used the cars data held in the EWS to code it to the car using NCS Expert thought the data was also held in the lighting switch unit, happy to be corrected.

There is no headlamp control unit as such on a Z3. I'm not sure the data is backed up on a Z3 anywhere other than the EWS. So the EWS effectively does what the headlamp control unit does on other BMWs.