Ingo,
I can turn the ignition on and not start the engine and there is no hum (high pitched whine!). It only appears when the engine is running. I do not have an amplifier, it is only the head unit and it is a 1972(?) Blaupunkt. The ground is connected to several other wires that then go to ground. Could this cause the "ground loop" or is there another problem?
Thanks much!
Quote:
Originally Posted by ischmitz
CDI stands for Capacitive Discharge Ignition. It is the silver box with the cooling fins on the electric panel in the engine bay.
It uses a DC/DC converter that runs with 3.5kHz. To check if that is the culprit simply turn the ignition to ON but do not start the engine. If the hum appears it is likely the CDI unit. If the hum only appears when the engine is running it still could be.
The fact that the hum is NOT changing pitch with engine RPM makes me think you could have a ground loop. Are you using an amplifier or only the head unit driving the speakers?
Ingo |