Have a Car Question? Ask a Mechanic Online.
Hello. So all this happened after you did a compression test? From what you are describing you have a loose ground on the engine causing communication issues. Check all your grounds and let me know what you find.
There is a couple different ground wires adding a ground will not do anything unless it was a problem with main ground wire. Look at the ones around the intake area tug on wires and be sure they are not broke inside insulation.
Is the check engine light coming on? Security light?
If the security light is on in the cluster it will not crank. Check connections at exam be sure they are plugged in
sorry it should have said ecm. Unplug it and be sure there are no bent pins. Unhook battery for a few minutes.