First do not turn key on or try to crank!
Fuel test if the vehicle has sat for over a year and with low fuel level means it was not properly stored. It is best to remove tank empty and rinse with denatured alcohol, replace fill with gas add Sta-bil , change filter. disconnnect gas line at engine, place clear bottle at open line in engine compartment, turn key on do not crank, incepct fuel., disconnect fuse to pump.
Usually coolant needs replacing drain, repalce with BMW blue with distilled water!
Next pull plugs oil cylinders inspect oil, if good crank and test compression they shoudl be about the same. IF oil is dirty change we recommend 20/50 non synthetic Vavoline and change filter then compression test. check spark.
replace plugs, fuse to Fuel pump and give it a try.
Good luck
