Well here is the scenario:

My newly installed Kenwood deck works great accept it turns off sometimes. It will stay on when the car isn't running, just in the acc position with no problem. If i cold start the car it will only stay on for 30 seconds roughly, then just power off. If the car is warm it will only stay on at idle, and when i rev the car it shuts off and the turns back on after a few seconds. Another time it turned off on a cold start and was off for 20 sec or so then i turn the head lights on and it turned back on.

One thought i had is my relocated battery ground is the issue. Originally it ran from the transmission to the body to the neg terminal, now i just have it going from the terminal to the transmission.

Another idea is that the alternator is over charging, i remember when i had to jump start the car with the jump box a few times before i replaced the battery , that it would beep and read "HI" on the screen after we jumped it, and my mechanic friend made a comment about it that being odd.

 

Not sure if this will help but I Installed a Kenwood KDC-BT558U in my 1990 Honda Civic last night. After I wired everything up, I went to turn the key, radio powered up normally, when I went to start, the car just died completely w/ all electric. Ended up disconnecting the negative terminal reconnecting and it did it again. I noticed I had corrosion on the negative(-) terminal and the terminal battery wire attachment. Cleaned em up and no more problems. I'd check your wire harness as well, make sure your ignition signal and +12V battery wires are correct.

 

i wiggled all the wires and it had no effect on it turning on or off, i think it has got to be a that ground wire or the alt is overcharging and the deck is turning off as a safety feature from too much power?

 

I see you wiggled em lol but are they color coded correctly, yea definitely sounds like a wire/ground issue or possible bad alternator. You can check the battery and alternator with a voltmeter (multi-meter). Hook it up to the battery check voltage, if it has 12V its enough to start and you can test the alternator. Start the car now with multi-meter connected and vary the RPM's. If voltage increases 13 -14.5 your alternator is ok, if it remains the same or decreases its your alternator.

 

Yea im going to clean up the grounds and test the voltage to the battery tonight

 

I re did the grounds to i nice freshly scuffed area of frame with a nice bolt with plenty of tight contact. Everything is back to the stock orientation. Transmission to chassis to battery

The radio would still only stay on if the car wasnt running, as soon as i would start the car it would begin to play and then the deck still just shut off.

I tested the voltage across the battery at cold start idle, like 1300-1400 rpm

Annnnnnddddddd......................... it was as suspected, 19.8 - 20 where it would than overload the meter, it rarely dipped below 19 Reminds of when we jumped it with the old battery and jump box the box's alarm would start going off.

I will be putting a new alternator in tomorrow, i hope i haven't damaged my new Odyssey battery.

 

Good stuff yea battery should be ok depeding on how many cycles its been over charged. Hope everything works out...music is key for road noise and awkward silent car rides lol

 

I replaced the alternator and now all is we'll, normal voltage at idle and proper radio function.