breadsc400

Hey all,

Have a 1995 sc400 with a very weird problem, thats starting to get worse. The voltage on the car drops way below 14, whenever my foot is off the gas or whenever my foot is on the brake pedal.
At night it would cause my headlights to turn off, it would cause my radio to turn on and off.
And Twice the car has actually died, the lights will dim the power steering goes and the car shuts off. Once you get on the gas its fine and doesn't have a problem at all, this is only when sitting still at a low rpm, or when foot is on brake for a long period of time. I have upgraded the alternator, I have aftermarket radio/subs, and lights. I still cant seem to narrow it down to what the problem is. Any help would be greatly appreciated if anymore info is needed plz let me know ill check back regularly. Also I hear a very weird whine/hiss in the car that sounds like its coming from the speakers, is this just my fuel pump/tank behind backseat because it gets louder as the rpm goes up, or is that a bad ground?

mitsuguy

iTrader: (2)

poor grounds cause the whine/hiss, but, a defective alternator could as well...

check your engine grounds - they are the most likely culprit, assuming the alternator is indeed good (new does not always mean good)

RTIS250

iTrader: (9)

A good place to start also, would be to disconnect your aftermarket amps from the battery so you can eliminate a faulty amp drawing too much power. Once you have eliminated that, i would inspect the alternator to make sure your connections are good. Im assuming since you said you upgraded it, it is aftermarket? Make sure your p/s pump isnt leaking onto it, causing it to go bad. Also, check battery terminal connections! Basics first...

The hiss/whine could be due to the routing of your RCA and power cables to your aftermarket amps... make sure your power wire is as far away from the RCA cables as possible.