i have a 2007 fit that i jus installed an audio system in keeping the factory head unit. i used a hi lo output converter (Soundstream Int.28x)
at times i get engine noise from it and now the system plays and cuts off ramdomly. the HU at times doesnt power up and then at times when its on, no audio output.
can anyone help me?

 

Noise can come from a variety of sources and the only way to find it is to take each component out and see if it still exists or start with one component and slowly add components back. The same for it cutting out it could be a problem with short from an RCA or a bare wire somewhere. Without dissecting the install its hard to pinpoint the exact cause.

 

I had the same problem in a different car but I fixed it when I ran the sub power cord on a different route than the RCA and Rem cables. I ran the power cord on one side of the car and the RCA and Rem cables on the other side of the car. The power cord can give off a frequency that creates the engine noise.

 

Engine noise is usually related to a ground loop issue, especially in aftermarket installs. The only way to fix that (if it is the issue) is to do research on ground loop noise and how it's caused. You'd then have to troubleshoot each component in your system that you grounded to make sure it isn't grounded twice

 

With line output converters noise is easily introduced into an audio system. Sometimes a simple grounding of the outter shield of the RCA's connected to the line output converter to the chassis of the radio can fix it. But you will need to as someone already said first do some testing to see where the noise is coming from. If your power wire and RCAs are ran down the same path to the amp, that is your first problematic area.