Is there a different voltage requirement for the new deck than the old?

A power or ground back feeding into the radio circuits?

OK one more guess.

Knowing you have a more modern engine swap,

Is it a collision shut off sensor or relay (air bag or fuel pump) that was shorting out the circuit ???????????

I was leaning towards the inertia switch as well but Dan said not power related or no power was lost.

I think it has to do with the fact you like to hear the engine so you turn down the radio until you get to a stop. When it's warm you have the windows down so can't here it anyway. ROTFLMAO.

Maybe its the FBI surveilance Team #3 following your ass around with electronic jamming equipment just so you can F**k with all of US !!

Alternator or battery. Charge/power of battery dipped below x volts and the stereo shuts off. Put in a new battery or alternator, presto.

My brain hurts.

My guess is in the starter relay. I had drop contactors act funny in spas, sending voltage to places it didn't belong. Its a guess, anyways. Easy part to swap out, too.

Chad

Head unit turning it off?
Maybe it had a thermal protection device and a short somewhere, like in your brakes or brake lights, that was interfering with the head unit or thermal device shutting it off. That's my last guess and then you can go straight to he'll mister.

Does this have to do with the ballast resistor used on the stock ignition wiring? I don't know much, I gutted my stock ignition for an MSD years ago, and never learned about points & other old junk. If the radio was using the wire from the stock ballast resistor as the switched leg, it could decide to turn off after a while. Back to over heating in the radio due to low voltage.

Don't know why it would turn back on though.

All right, I'm done guessing.

I don't fully understand the EEC-IV yet or how it might control power to the stereo....unless its through the ignition switch. So does it have to do with the HEGO failing and sending a bad signal to the EEC?

I'm sufficiently stumped. The fact that the problem is NOT in the cab is throwing me off. Here's what I've been able to piece together so far.

Putting together the theories of Zoso, Badlands, and CC, it would have to be wiring related. Something to do with a ground. Dan says fair knowledge of old and new school electronics is required. The issue had something to do with two items, because Dan said he repaired one, and replaced the other.

My guess is the speakers. Resistance in the wiring doesn't jive with the new stereo.

Your train horn ground? LOL
Was it related to the EFI / manwell to auto swap or just coincidence?
Man I've re-read this thing a dozen times and my brain still hurts.

It shuts down because its to cold?

Why would the size of an amp shut it down?.......never heard that one before.

Well I for one am stumped, shocking I know - Greg, stumped by an electrical issue , who would have thunk it. I wish you smart guys would figure out, out, I want to learn...

Excessive voltage? (instead of to little)

Loose battery cable?

Solenoid

I'd say diode ....but that is integral with the alternator. Coil? The little canister on the dizzy I can't remember the name of?

He said it wasn't the battery......I'm lost since the regulator is good.....maybe a fuel pump? Since we're half way there, I'll leave it to the experts now:)

ECU/regulator not turning off the alternator? That why I asked about the regulator. I've never seen one underpower always over power. I know on my buddies powerwagon when the regulator went the voltage was up towards 18V's.

The yellow (voltage sensing) wire came uncoupled at the alternator.

Ok, then the regulator was toast.

Do you have 2 batteries in this?

Then something wrong with reg grounding.

Where are you running the hot wire to the stereo from?

weather pack connector on rjm pigtail??
or how a bout bad mega fuse housing??? a shot in the dark