They will most likely look at the compression as well when they check it. They will also look to see if it something mechanical in the valve train.
You have done the basics but it leaves only something mechanical.
As far as the draining, a parasitic draw test needs to be done to see how many amps are drawing on the battery with the engine off. Once that is determined and then they will need to isolate the circuit that is causing the draw. Then they can determine what is causing the draw.
Roy
Thursday, September 20th, 2018 AT 1:18 AM