FeynmanSum

Hello, I have found myself with a power issue related to my car computer, i believe to be the alternator or amp, but I would like other opinions. I do not hear any alternator "whine", so that is why i would appreciate some advice, thank you in advance.

Equipment:
1989 Volvo Wagon, original alternator, brand new Die Hard battery

Amp: Phoenix Gold (couple years old, purchased used)
Computer: Via Epia SP13000 running off a Opus 150W supply

Problem Description:
When I connect the cable that delivers power to my amp and car computer, after an hour or two of highway driving, I find that it trips my car's ECU into malfunctioning, ie, no longer properly regulating fuel injection. I have tried just unplugging the computer, but the problem remains, which makes me think it's amp related. I also noticed, when my computer is turned off, that I will occasionally get a loud buzzing noise from my speakers, that won't turn off until i unplug the amp. When I disconnect the power to both the computer and amp, the car runs fine and I have not had any problems to date. So is this an amp problem, grounding issue, am i supplying insufficient power? Thanks again.

MP3Car.com

 

billmee

Dr Feynman I presume?

Sounds ground loopy.
What are you connecting with big fat 4awg and is your ground the same gauge.
Are Opus and amp grounded to the same point?

FeynmanSum

Indeed.
The ground is not the same gauge, it appears to be slightly smaller, and is connected to the frame near where the amp is installed in the back of the car. The opus power wires are connected at the same screw-down contacts that the Amp uses. Is there a convenient way to test for improper grounding? Also, could it be related to something going on inside the amp? The reason I ask is it does not manifest itself all the time, but seems to more often when the car (and thus the unit, since I have no AC) is hot.

MP3Car.com