I have a Ferris zero turn with Briggs Vanguard 810 EFI (49E877-0001-G1) Lost spark on left cylinder, switched coils around, realized they both work on right side and neither work on left. After troubleshooting the wiring i decided maybe a bad ECM. Got a new one from Briggs (original oem part) and replaced it. Now i have spark to both cylinders but the engine will not start. Doesnt appear to have any fuel or the injectors are not working. Does a new ECM require software installation prior to being installed? I'm really not sure which way to turn at this point. Thanks in advance for any information you can give.