BMW Z3 will not start or starter does not turn: electrical faults
Z3 2.8Z3M
Z3 will not start or the starter only turns briefly: where should the check begin?
Start with the electrics. Clean the battery terminals and cable lugs, make sure the battery is in good condition and clean the mountings of the alternator cables. Also measure the engine earth. A dirty terminal can drop the voltage in the engine bay clearly below the battery voltage.
Can a missing earth stop the Z3 starter from turning?
Yes. If the earth lead between the engine and the body is missing or poor, the starter may not turn even though the battery and the starter's trigger current are fine. A proper earth to the engine mount has fixed the fault.
Why does the Z3 rev counter act up and the car stall and not restart?
The cause can be a loose thin wire running from the battery positive to the engine. Check the wire mountings and tighten them before suspecting more expensive parts.