I have a Roco HO BR44 with sound (#62325). The chuff sound fades out and in when the engine is running at 26 to 30 smph. Any idea as what if any cv changes will correct this? I've done resets to no avail. Second, I would like to cause function 4 to sound the short whistle and function 9 to sound the conductor's signal. Which cv changes are required to accomplish that?