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Aftermarket stereo suffers from white noise when the engine is running.


BlueKrogan
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So I just swapped out the Pioneer single din that it came with my Pathfinder for my Pioneer double din touch screen; it looks really nice with the dash, but I digress.

 

When the engine is off, the reception is crystal clear, however once the engine is running it is a totally different story. This also happened with the single din head unit that it came with it as well, although the one I installed isn't as bad.

 

I checked the head unit's ground wire, and regardless if it's grounded or not, it literally doesn't make a difference: I still get crystal clear reception with the engine off and static/white noise  with the engine running.

 

Certain stations are unaffected as they are pretty well known to transmit powerful signals, but the ones that are affected still work pretty good on any other car and even worked fine when I had this head unit on my previous vehicle; it's like the affected stations don't transmit a signal powerful enough to combat this issue.  

 

I don't know what else to do, any help would be greatly appreciated.

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Is there any correlation between the noise and the speed of the engine, or how many electrical loads you're running? 

 

Absent any better ideas, I would unplug the alternator (or remove its belt) and see if that kills the noise. The alt makes 3-phase AC and the diodes inside rectify that to DC, so if one of the diodes goes out, the alt could be dumping all kinds of noise into the electrical system. 

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I had this happen on mine and lived with it for years, turns out it was the alternator. You could try getting one of those ground loop isolators and see if that helps? Doesn't make sense to replace a working alternator.

 

Also - another Ontario first gen? Where at? These are a rare sight these days and I don't even drive mine in the winter... Frame will rot out too fast lol.

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14 hours ago, adamzan said:

I had this happen on mine and lived with it for years, turns out it was the alternator. You could try getting one of those ground loop isolators and see if that helps? Doesn't make sense to replace a working alternator.

 

Also - another Ontario first gen? Where at? These are a rare sight these days and I don't even drive mine in the winter... Frame will rot out too fast lol.

 

Toronto. It's been regularly rust proofed , so I've been lucky. I'm going to take it to get rust proofed, but I don't know if I should go Krown or Rust Check. The previous owner told me where he got it done they used something that was thicker, and wasn't the thin runny oil. 

 

Anyways, so far the general consensus has been the alternator. 

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On 10/6/2022 at 4:41 AM, Slartibartfast said:

Is there any correlation between the noise and the speed of the engine, or how many electrical loads you're running? 

 

Absent any better ideas, I would unplug the alternator (or remove its belt) and see if that kills the noise. The alt makes 3-phase AC and the diodes inside rectify that to DC, so if one of the diodes goes out, the alt could be dumping all kinds of noise into the electrical system. 

 

Nope, when I rev the engine the static is pretty much the same.

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  • 1 month later...

Do you have any rca wires running an amp? 
 

Sometimes the rca wires ran near the power wire, if you have an amp hooked up, will cause issues. 
 

If it’s just the head unit with no amp, plug wires are likely causing the issue. Why it effects the radio, I’m not sure. Could be spark plug related as well. 

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  • 1 month later...

So tonight I just discovered that a running engine isn't the only cause of making the radio's reception eat @!*%.

 

On 10/6/2022 at 4:41 AM, Slartibartfast said:

Is there any correlation between the noise and the speed of the engine, or how many electrical loads you're running? 

 

Yes. When I turn on my headlights, the radio's reception suffers. I wish I would've noticed and tested this sooner instead of just jumping to conclusions by solely blaming the running engine.

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Still sounds consistent with a bad alt to me. The lights take power to run, the alt has to generate that power, so if the alt is weak, makes sense an added load would make it worse.

 

Unless you mean turning the lights on kills the reception with the engine not running--that's a different and entirely more puzzling bag of crabs.

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All these issues sound like a ground problem. Did you run a separate ground for the radio or just have it grounding through the antenna (the actual ground in aftermarket harnesses doesn't connect on these trucks, they use the antenna and the metal dashboard frame as ground).

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So I did another test, when I flick the high beams on with the engine off, the reception takes a hit, so I'm wondering if its strictly due to the headlights since they're on when the engine is running, and when I turn on the night time headlights, it compounds the issue since it draws more power.

 

19 minutes ago, adamzan said:

All these issues sound like a ground problem. Did you run a separate ground for the radio or just have it grounding through the antenna (the actual ground in aftermarket harnesses doesn't connect on these trucks, they use the antenna and the metal dashboard frame as ground).

 

I wrapped the aftermarket harness ground wire around what I assumed to be a good grounding point; it seems like whether I ground it or not, it doesn't make a difference :s

 

Maybe I'll find another ground point; where did you ground your wire? I'm starting to think that I'll never find a solution to my problem :(

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  • 1 month later...

Try running a separate ground wire from the stereo chassis to a good body ground.

 

It is possible the DRL module could be causing your electrical noise. If you unplug that and the noise is gone, then you found the problem. 

 

Is the noise only in the radio or all the stereo functions? If just radio, possible issue with antennas or wires. 

 

You can also try a noise filter on the power wires for the stereo, the yellow always hot wire is the one you will want to filter. The red is only for switching on and off. 

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I've had to install a few VHF radios in some trucks, but one I had the antenna run near a power cable for a light bar, and on another truck it was looped back on itself. Both of these had terrible reception and one had static only when the truck was running. Make sure the antenna cable is insulated very well. Adding more insulation and unlooping the other fixed the problem.

Edited by Strato_54
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