Custom sound problem for engine (playing both soundGroup and default)

So I got my custom sounds to play for my engine.... but its also playing the default sound as well so it sounds terrible. I commented out the "default" sound and it does work correctly so I know this is the issue that its for some reason playing both sounds... I do need the default sound for the other default engines...

In my custom engine jbeam file.... I do have the soundGroup...
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"engine":{
"soundGroup":"diesel",
},
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And here is my sbeam file...
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{
"modifiers":[
["name", "source", "factor", "offset", "min", "max"],
["engine_throttle", "engineThrottle", 1, 0, 0.65, 1],
["turbo_throttle", "throttle", 0.5, 0, 0.1, 0.4],
],
"sounds":[
["group", "filename", "profile", "nodeName", "source", and so on... ]
["default", "V8_default.ogg", "AudioDefaultLoop3D", "ENGINE", "rpm", and so on... ]
["default", "turbo_03.ogg", "AudioDefaultLoop3D", "ENGINE", "turboRpmRatio", and so on... ]
["diesel", "diesel_engine_idle.ogg", "AudioDefaultLoop3D", "ENGINE", "rpm", and so on... ]
["diesel", "diesel_engine_high.ogg", "AudioDefaultLoop3D", "ENGINE", "rpm", and so on... ]
["diesel", "diesel_startup.ogg", "AudioDefaultLoop3D", "ENGINE", "rpm", and so on... ]
}
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Please let me know if you have any ideas of what I could be doing wrong here... thank you