Need an automotive electrical engineering genius...

[sb001]

to diagnose the weirdest problem I've ever seen on my 03 Maxima.

The car has an in dash Bose 6 CD changer, tape deck, radio combo. About 90% of the time the CD mechanism has loads of trouble reading a disc -- it skips, pauses, mistracks, won't find the next track, etc...-- But ONLY when the engine is on! As soon as I turn the engine off, it immediately starts playing perfectly with no hint of problems. Turn the engine back on and BAM all sorts of issues again.
My first thought was that it was simply the vibration from the engine, so I removed the unit from the dash (leaving it plugged in), placed it on pillows on my knee to isolate it, and tested it that way and it still had the same problem. VERY occasionally it will play a disc all the way through with the engine on with no problem, but very rare. Having the engine on also does not affect the radio or tape portions of the unit they both work fine, it's just the CD mechanism.
Is there anything within the CD portion of this thing that would be adversely affected by having the engine on, say for example oh I don't know- some kind of rectifier that suppreses voltage surge only when the engine is on? And only in the CD mechanism? Contrary to most factory units I actually like the way this system sounds when working properly, so I'd like to see about getting it working right. Nissan dealer is obviously a waste of time. Need an actual electrical guru to tell me what's going on.
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I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[KTPhil]

I'd start by measuring the voltage present at the radio power terminals with the engine at rest and when running. Maybe it's fine on the 12V of the battery, but if your alternator is overcharging, maybe the excessive voltage is tripping up some circuit.

[Manfred58sc]

I used to build and test CD-ROM, the boards have all sorts of diodes to clean up power. Sounds like one failed. I bet a used one could be had for like $20 ( from one of the many used parts sites representing various junkyards), since hardly anyone listens to CD's anymore.
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Fat chick owner/operator

[sb001]

[busdaddy]

Then it sounds like you'll have to install some sort of voltage regulator circuit in it's power supply line.
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[sb001]

[VOLKSWAGNUT]

Yes a funky charging alternator can cause all sorts of electrical mysteries.. especially if a rectifier is bad..

Agree... if its overcharging... it cause mayhem as well ..

Had a Buick once.. that ran fine.. intermittently the Alternator would wack out on its own .. would spike output 16 volts.. and modules would randomly shut down as self protection.. and then wake right back up the next key cycle.

Measuring the voltage before, during, and after cranking may tell the tale.

Thats fairly easy to diagnose .. Disconnect the alternator electrically.. crank and start the car.. if the issue is gone suspect the alternator.. . You just cant run it for a long time.. It may last a half hour without it charging...


Ill add another common issue into the mix that effects the entertainment buss and "modules" after engine cranking..
If the starter motor amps are too high during cranking.. or battery cranking amps is high and voltage is too low during cranking. .. TILT...

While you may not notice anything unusual during cranking.. .... a large current flow to the starter can rob available voltage to other circuits..
In other words.. while the engine is cranking.. the radio is trying to boot on the low voltage... it goes wacko..
Its the ole GIGO.... garbage in..garbage out..way of thinking.

Make sure the simply battery terminals and connections are clean and tight. Check the main ground from the battery to the body/engine as well.

The battery is the main "noise" filter.. make sure it good as well.

All that noted,,,, it could still be a stupid radio in the end...

.
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[sb001]

[VOLKSWAGNUT]

[skills@eurocarsplus]

junk aftermarket coil packs do all sorts of neat things too
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[VOLKSWAGNUT]