A little help. No sound when engine is running.

rodneypierce · Mar 19, 2012

I posted this in the general section as well, but not sure if that is the right section or not. So figure it might be better suited here.

Alright, I have a 98 Grand Prix GTP. Just recently installed a system in the car (couple months ago maybe tops)

I have blown 2 subs since (just blew the second one this weekend). I didnt think anything of the first one, as it was old, and I thought one of the voice coils was on the way out anyhow. Well, when this second one blew Im starting to wonder. Each time the sub blows, it kicks the amp off. The radio and everything is still working, just no sound. (gains for sub are set with a DMM, so I know its not due to too much wattage and shouldnt be from clipping).

Now here is where Im stumped. Now, with the car running, there is no sound at all. Amp is on, radio is on and working, but no sound out of the speakers. With it in acc or just on, but not started, everything works perfect. Start the car, and no sound, but everything is on.

I checked voltage at the alternator, and at the battery and fuse box lugs. Its 14.5 at the alternator, and 14.0 at the fuse box lug.

MB Quart 5 channel amp. Eclipse CD7200MKII head unit. Aura 6.5 components.

Any help is appreciated with this. Or even what else to check/trouble shoot. Im lost!

*EDIT* Alright, it doesnt trip the protection on the amp, as the protection LED never lights. It also plays for about 20 seconds when on before the sound stops. Everything else is still working, just no sound. Now get this. I shut the door, let it play until it cut out, then turned the car off (stereo continues to play until you open the door) and a few seconds later, the sound came back. So I havnt a clue here. Clearly the RCA cables and power wire should be fine, as it will play all day long in acc or when the key is just on, but the engine is not running. Once the engine is started, no sound after a few seconds.

quickaudi07 · Mar 19, 2012

That some wired **** man, let me ask you this, did you use wire-ring kit for your head unit? if you did, i would look for turn on ACC at some other location, also how did you install your remote wire for your amps? is it coming from the HU? or other other location?

Also have you looked at your grounds, see if anything got lose?

Also as you stated that your subs keep blowing, are you looking at the ohm load that the amp could take and what your subs are? its very important that you put proper ohm load on the amp, or you will fall in to complications and may damage either your amp, or subs.

My friend had the same problem where amp will go in to protection, and it will turn on fine when the engine was turned off, after doing some trouble shooting on his car, I have found lose and gad ground points.
After redoing and rewire-ring his grounds, his sound system sound way much louder and better because of better ground.

Other than that, Its really to find the problem,

But I would start with all your grounds, and power connections.

Good Luck

rodneypierce · Mar 19, 2012

quickaudi07 said:
That some wired **** man, let me ask you this, did you use wire-ring kit for your head unit? if you did, i would look for turn on ACC at some other location, also how did you install your remote wire for your amps? is it coming from the HU? or other other location?

Yes, I did use a wiring harness adapter. And the remote turn on lead is ran directly from the HU's harness to the amp

Also have you looked at your grounds, see if anything got lose?

I checked them at the battery, and they were good. I will check at the amp tonight. (have to remove the backseat to get to that end of the amp)

Also as you stated that your subs keep blowing, are you looking at the ohm load that the amp could take and what your subs are? its very important that you put proper ohm load on the amp, or you will fall in to complications and may damage either your amp, or subs.

Yes, both subs were under rated for the amp. Amp is 2 ohm stable. Was running the subs at 2 ohms. MB Quart DWG-254 DVC subs. Single 10" wired at 2 ohms.

My friend had the same problem where amp will go in to protection, and it will turn on fine when the engine was turned off, after doing some trouble shooting on his car, I have found lose and gad ground points.
After redoing and rewire-ring his grounds, his sound system sound way much louder and better because of better ground.

Ill check at the amp tonight. But that is what has me stumped. It doesnt go into protect? (according to the LED on the amp)

Other than that, Its really to find the problem,

But I would start with all your grounds, and power connections.

Good Luck

Posted my replys in blue.

minbari · Mar 19, 2012

try disconnecting the ACC wire from the HU, amplifier etc. start the car, then connect it.

if the voltage is dropping out when you start, maybe a low-voltage circuit is turning it off.

rodneypierce · Mar 19, 2012

I will also try this tonight. If this is the case, is there a way to remedy it?

deesz · Mar 19, 2012

The one that I see all the time is bad fuses. They look ok but inside of them the solder points are bad. It could be allowing for enough voltage to run through it with the car off but once it's started it doesn't supply enough. Just something to consider that's easy to test for.

rodneypierce · Mar 19, 2012

But all the lights on everything stay on. Ill check the fuse tonight as well.

rodneypierce · Mar 19, 2012

Alright, I did all of the above, and it still did the same stuff. It even kicked off sound when in acc this time. But i was only able to get it to do that one time. So pulled the amp and yanked the back cover off. Not sure if this would make it do what it is or not, but it cant be good. Here is what I found:

rodneypierce · Mar 19, 2012

and a little more:

minbari · Mar 19, 2012

Burned resistor going to one of the output devices. And a burned output device. It needs repair

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rodneypierce · Mar 19, 2012

Minbari, I figured as much. This amp doesnt owe me anything. I have had it for years. I am currently searching for a replacement and will probably put this one up for sale, or just toss it out.

quickaudi07 · Mar 20, 2012

Damn it looks like you are going to be doing some shopping

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rodneypierce · Mar 20, 2012

Already on the way

. Boston Acoustics GTA-1105 and a ID10 S4 V3.

I am going to attempt to fix this one myself though for a backup. Just have to order a couple of parts.

A little help. No sound when engine is running.

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