NotLawReview

Back in June of last year I purchased an '04 C5Z to replace essentially the same car that was totaled in the Memorial Day floods that we had down here in Houston.

The car I purchased was a former show car, and had a nice system in it that worked flawlessly until November of last year, when I started experiencing voltage drops that would send the amplifiers into protection mode.

The system is composed of a JL Slash 300/4 powering 2 sets of Boston Acoustic Components (F&R), a JL Slash 500/1 powering a 10" JL 10W3v3, and an Alpine CDA-7995 head unit.

When the car started experiencing the voltage drops back in November, I was getting all sorts of issues ranging from the car surging/bucking due to misfires, the oil pressure gauge reading no pressure, etc., but the issues relating to the audio setup were a little bit simpler; whenever I would turn the volume above level 17 (~22 is necessary for windows down entertainment) the amplifiers would both cut out momentarily until a break in the music, or until I cut the power back down to 17 or below, and would then resume play.

At this time, the battery in the car was an Optima Red Top with a '13 production date, and after a little reading I found that a Yellow Top would be better to power a decent system, so I ordered one of those. I also ordered a new ignition switch and did new plugs/wires for the engine.

After I swapped the battery, ignition switch, and plugs/wires in the first week of December, everything was PERFECT.

Until this week.

Starting this week I had a few DIC errors relating to the communication between the various modules in the car (all related to the ignition switch), and I then began having the issue where I cannot turn the volume up above level 17 without the sub amp cutting out first (different than last time when both cut out at the same time) with the amp powering the speakers cutting out a little bit after, usually at different volumes from each other (typically 18 for the sub, 20 for the components). Knowing what worked a little over a month ago, I went straight for the ignition switch.

Now, this was a brand new unit that I had installed in Dec. and when I got it open it had carbon fouling on the contacts 5x worse than the 10 year old unit that I pulled out previously. I then took the time to clean them up with 800 and 2000 grit sandpaper, cleaned them with isopropyl alcohol, re-bent them to keep tension, and put it all back together and reinstalled it in the vehicle, and wouldn't you know it the issues are still there.

This is driving me crazy, and I'm looking for some guidance as to what other issues could be causing a voltage drop that would put these amps into protection mode?

The only things I can think of are:

-The PO who installed everything ran the grounds from the amplifiers (located on the shelf behind the seats) all the way back to the battery, and I was thinking that I should maybe shorten the ground wires to the bolt of the passenger seat
-The current draw might be too much for the alternator? I have tested the alternator myself (and had autozone test it) and everything seems to check out....
-Maybe the head unit is on its way out? Amps?

I would appreciate any of the sage wisdom that I've seen on this forum very much!

Thanks!
Pat

yamabob

I would run the ground to the shortest path possible first. Also what AWG for the amp. I would run 4.
The alt on your car may not be up to the task. Check as I think you might have a 110 A.
You start drawing down on the power and she may not be able to keep up. That would be my starting point

NotLawReview

It's 4 gauge for both the power and the grounds for both amps.

The 2004 has a 145A alternator, so I'd think it should be fine?

Weird thing when i went to pick up lunch today, I tried messing turning the gains up to see what would happen, and it didn't seem to make a difference, and then i got pissed and cranked the volume after everything cut out and I left it there, instead of dropping it down like i have been doing, and when the music came back on it stayed on; would there be a reason why this would happen?

Update: Tried to crank it up past the cutout on the way home, and it would come back but continue to cut out. I kept an eye on the DIC and the voltage did not drop in the DIC when the audio would cut out.

markcz

I don't think your issue is with the radio or amps.

It sounds like you have a loose or corroded connection somewhere that's limiting the available current flow from the battery. Turning the radio up is just the straw that puts total current flow over the limit.

Try removing/cleaning/replacing the + wires at the alternator and starter motor.