Sounds like loose/bad connection somewhere. Tough stuff to track down.

The fact that it goes away after an hour makes me want to rule out problems like low voltage due to inadequate wiring, capacitor problem, wrong connections, etc. None of those things are going to cure themselves after an hour of running.

I'd put some tell-tales on the car to see what's going on. Insert an LED in series with the amp turn-on lead to verify current. The LED should light whenever the amp is on. If it goes off, either the source of the turn-on voltage disappeared or the amp lost it's ground. You can place it where it's visible all the time so when the sound quits you can check it right away.

You can also put a small speaker directly on the HU speaker outputs to monitor the HU audio. Chances are if the HU is internally losing the audio signal it will kill the HU speaker output too.

You can also put a small value fuse (1/4A) from a known good ground to the amp ground terminal (the one on the amp). If the amp ground ever goes open or even goes high-resistance, the amp will pull it's power through the 1/4 amp fuse and will blow it, leaving a permanent indication of the bad ground.

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Thanks guys for all the feedback! I've heard all the suggestions that you guys have made and they all make sense until you read my note up top that it only does this for the first hour and then I can drive it however I want or turn it up as loud as I want and it will be ok. Go figure? I know the end of all this is probably rewiring the whole system again.

 

And if it's not in the wiring you're going to do a whole lot of work with no results.

This is why I mentioned seperating out the system into to parts (pre-amp, post-amp) and working from there.

Once you've isolated the region the problem is coming from you have a better idea of where to start.

This could be something as goofy as a bad set of RCA's (got sliced on install, so they are loose but as they heat up from some external heat source the plastic jackets expand enough to make the connection again) to a bad pre-out on the radio to the sub's voice coil warming up strangely and being bad.

Is it any of these things? Probably not. But until you isolate the problem you're just throwing time at it.

 

Unless the alternator has something to do with it. After an hour or so, that thing will be producing some power for the batter. I dont know the schematics of how the alternator affects current throughout the circuits, though. I would think that you are probably over drawing something, and it goes away once the alternator kicks in its charge.

I would get a multimeter, and test the power in, ground out, remote turn one, etc. All with the car cold. Have a buddy check the readings on each wire, one reading with wipers off, another with wipers on. If when the wipers kick on, the voltage drops below minimum values, that is your problem. EIther bad wires, bad fuse, or just over drawing something.

John

 

Pulse what's your background?

 

i dunno... at this point, i've just about given up on this thread.

we've given Dieu a few suggestions, and he's essentially not given back. until we've got more data or hopefully he's performed some of our recommended checks, we're not working on anything new.


and regarding the 1 hour thing? a loose underhood connection might see expansion from heat (and thus close up) over time. i'm still not sold that it isn't something loose.

 

Not as much as some of you!

Been installing my own systems for around 17 years. Also worked on many other cars (mostly friends, club members, etc).

Also spent a few years working as an installer for Circuit City (not all of their installers are just hourly slaves!)

Most of the installs I've worked on were your basic HU/Amp/Cap installs, but I've had my hand in more then a few big systems (though box building isn't my thing, I can do it, but I'm not great at it).

My biggest strength is design. Give me a car (let me sit in it and so on) and I can usually put a good system together that the owner will be more then happy with. Can, usually, stick to the budget to.

I lean toward stealth systems, like to surprise people as I pop open panels, flip hidden switches (I always put a cut out switch on the remote wire to my sub amps "it's broke officer, I promise!") and so on.

I've done it for a living before, and it was one of the few jobs I truely enjoyed, but I've moved on to software design (for now!). But I'd jump at any stereo job that had a similar pay check.

 

Never saw this thread before... mas beat me to it. If the sound truly fades back in (not cuts in, but fades), I would look VERY closely at anything having to do with the mute wire.

 

interesting....


good to know.