As the title says, I believe I am experiencing some voltage issues.

Specs on the car: 1999 civic SI, JDM B18C motor, 95 GSR computer, hondata s300, GSR alternator (brand new), and a odyssey pc680 battery (2 months old).

Symptoms: If I have the air blowing and my music on at the same time, the check engine light flickers. It's not a flash but a flicker and it is not fully lit up either. For example, the light gets brighter when the bass hits and then dims/goes away when it doesn't. If I turn the air off, the light stops flickering and goes away. This has been occurring more and more so I'm trying to get to the bottom of it.

When I start the car in the morning there is no CEL and it starts fine. After about 5 mins of driving down the highway it begins to act up. It doesn't effect the way the car drives but I see this as a problem.

Has anyone experienced this or have any idea what I should be looking into?

Thanks!

 

music - sub? amp(s)? or just the radio powering speakers?

have you checked your ground wires?
what adapters did you use for the battery?
do you have a volt meter?

 

Small lightweight race style batteries are not designed to support high drain accessories such as high-current amplifiers and A/C coil/compressors. Get a normal battery and see if your problem goes away. Race cars don't have A/C or big stereo systems... and street cars don't need to save fifteen or twenty pounds in total vehicle weight by switching to a low reserve capacity battery.