John S
06-09-2008, 12:00 PM
Ok, I've got a problem and I was hoping that there is a bona fide car stereo expert lurking around that offer some advice.
I've got a real bad (loud) hum/popping sound in my system. With the Key in ACC it sounds great, very clean no electrical noise. If I turn the key to on I get an initial high pitched squeal that dies down into a low popping sound then stops, when I start the engine hum/popping starts up. It's not ignition noise and it does not vary with RPM. And only happens when the cars electronics are on. The electronics consists of:
FAST XFI ecu
MSD 6a
MSD blaster coil
Aeromotive A1000 electric fuel pump with the pump controller.
MSD one wire alternator
I've checked all the grounds and power leads, disconnected the RCA leads from the stereo to the amps and even swapped them out, I even installed the ground loop isolators in the RCA outputs from the stereo.
I run 3 amps in the car, I do not get any noise at all from my sub amp, but I do get it from the 4ch amps controlling my rear speakers and the 4ch amp on my front speakers. All three amps are grounded to the chassis with a 4awg ground and the power to the amps is from a 2AWG lead connected directly to the battery (engine comp)
Although loud the level remains constant and I can drown it out with the volume control.
Since it only happens when the key is ON or the engine running I though it might be related to the MSD or pump but I dont know of any way to bypass them and test it out.
I dont know where to look next.... any advice sure would be appreciated!
I've got a real bad (loud) hum/popping sound in my system. With the Key in ACC it sounds great, very clean no electrical noise. If I turn the key to on I get an initial high pitched squeal that dies down into a low popping sound then stops, when I start the engine hum/popping starts up. It's not ignition noise and it does not vary with RPM. And only happens when the cars electronics are on. The electronics consists of:
FAST XFI ecu
MSD 6a
MSD blaster coil
Aeromotive A1000 electric fuel pump with the pump controller.
MSD one wire alternator
I've checked all the grounds and power leads, disconnected the RCA leads from the stereo to the amps and even swapped them out, I even installed the ground loop isolators in the RCA outputs from the stereo.
I run 3 amps in the car, I do not get any noise at all from my sub amp, but I do get it from the 4ch amps controlling my rear speakers and the 4ch amp on my front speakers. All three amps are grounded to the chassis with a 4awg ground and the power to the amps is from a 2AWG lead connected directly to the battery (engine comp)
Although loud the level remains constant and I can drown it out with the volume control.
Since it only happens when the key is ON or the engine running I though it might be related to the MSD or pump but I dont know of any way to bypass them and test it out.
I dont know where to look next.... any advice sure would be appreciated!