ignition noise?

1986 chev 2wd pickup...350 engine that smoked the alternator about 2 yrs ago and replaced it (nothing thought of it). since then, running the truck by
houses with satellite causes interference big time, but still nothing thought of it.
now a higher end audio system installed has a wicked buzz in the speakers thats rpm related. not typical alternator whine....
could it be that when the regulator in the original alternator fried and the voltage when sky high, did it smoke the capacitor in the distributor that supresses RFI and now its noisy as hell???
what else would cause such electrical noise?? its definitely in the electrical system cause I unplug the RCA cables and the noise stays....so its not coming from the head unit. regrounding the amp to various locations and even the battery causes no improvement.
thoughts?
b
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Bad ground. Try moving the ground for the deck to a true chassis ground instead of the grounding wire.

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Interesting.....however, by removing the the RCA's, I would think we completely isolated the head unit from the amplifier since the signal is the only connection between the head unit and the amp. In past installs, if the head was inducing the noise, unplugging the RCA's killed it and you knew right away where the prob was.....not here.
It is my belief that the amp is picking up the noise from the power system, not the head unit.
I'm still curious....this truck causes static/interference with satellite tv as well....this tells me its pumping out a ton of RFI...which leads me to believe the ignition system is malfunctioning....any thoughts as to a fix?
b

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You could try replacing the plug wires with a better quality set. You could also try a new location for your amps ground. Had a truck come in the shop with a similar problem and just by doing that, it was corrected.
If the noise is still there, when the RCA's are unplugged, even a ground loop isolator won't correct the problem, because that is not where it is originating.

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the first thing I tried was re-grounding the amplifier to multiple points, with no reduction. And since the noise is still there sans-RCA's, it definitely is being induced through the power system.
I don't EVER use ground loop isolators as they are nothing more than a cheesy bandaid (even if it would help, I wouldn't use it!) This is actually not a normal condition...have had hundreds of cars in the shop with large installs like this with NO noise problems. this makes me think there is something going on with the truck....
we still haven't addressed that capacitor in the distributor...would it being damaged/nfg cause this noise?? I instructed the customer that a good idea would be fresh plug wires as his are aged...but the wet test reveals no leakage.
like I said...have had dozens of this generation pickup in the shop and this is the first noisy one I've had...
????
Hamilton Audio Car Audio, Security and Performance

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I'm sure it has nothing to do with your ignition system or grounding. I had 2 cars (1 chev, 1 older BMW) that had the same problem. There is a hot (power) wire laying across or too close to your speaker wires, after time the insulation breaks down or the caseing is damaged and "white noise" is picked up by the speaker wire. And it usually fluctuates with engine speed, as the alternator changes output. I did alot of research on my BMW, as this was the first car it happened to, and found that it is a common problem for older bimmers. So, I could imagine it could be the same problem.
| > > > > 1986 chev 2wd pickup...350 engine that smoked the alternator about 2 | > yrs | > > > ago | > > > > and replaced it (nothing thought of it). since then, running the | > truck | > > by | > > > > houses with satellite causes interference big time, but still | nothing | > > > > thought of it. | > > > > | > > > > now a higher end audio system installed has a wicked buzz in the | > > speakers | > > > > thats rpm related. not typical alternator whine.... | > > > > | > > > > could it be that when the regulator in the original alternator fried | > and | > > > the | > > > > voltage when sky high, did it smoke the capacitor in the distributor | > > that | > > > > supresses RFI and now its noisy as hell??? | > > > > | > > > > what else would cause such electrical noise?? its definitely in the | > > > > electrical system cause I unplug the RCA cables and the noise | > > stays....so | > > > > its not coming from the head unit. regrounding the amp to various | > > > locations | > > > > and even the battery causes no improvement. | > > > > | > > > > thoughts? | > > > > | > > > > b | > > > > | > > > > | > > > | > > > | > > | > > | > | > | |
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Not possible luke. ALL of the speaker and power wire used in the vehicle was laid fresh as of that day. ZERO useage of factory wiring save for the power, ignition and ground for the head unit.
Before you say the head is inducing noise, I can disconnect the RCAs (which removes head signal) and the noise remains. There is clearly noise being induced into the power system by the ignition....
tell me this...why would the truck cause television interference? cause the ignition is kicking off a LOT of noise!! snowmachines with non-resistor plugs used to do this at home (lived on lake superior) you could see the tv mucking up long before you heard/saw them.
so I'm thinking the same thing....any other thoughts?
b

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Hmm, that's interesting. It could very well be that ignition system somewhere. That's something I've never seen before.
| > | > > > > 1986 chev 2wd pickup...350 engine that smoked the alternator | about | > 2 | > | > yrs | > | > > > ago | > | > > > > and replaced it (nothing thought of it). since then, running | the | > | > truck | > | > > by | > | > > > > houses with satellite causes interference big time, but still | > | nothing | > | > > > > thought of it. | > | > > > > | > | > > > > now a higher end audio system installed has a wicked buzz in the | > | > > speakers | > | > > > > thats rpm related. not typical alternator whine.... | > | > > > > | > | > > > > could it be that when the regulator in the original alternator | > fried | > | > and | > | > > > the | > | > > > > voltage when sky high, did it smoke the capacitor in the | > distributor | > | > > that | > | > > > > supresses RFI and now its noisy as hell??? | > | > > > > | > | > > > > what else would cause such electrical noise?? its definitely in | > the | > | > > > > electrical system cause I unplug the RCA cables and the noise | > | > > stays....so | > | > > > > its not coming from the head unit. regrounding the amp to | various | > | > > > locations | > | > > > > and even the battery causes no improvement. | > | > > > > | > | > > > > thoughts? | > | > > > > | > | > > > > b | > | > > > > | > | > > > > | > | > > > | > | > > > | > | > > | > | > > | > | > | > | > | > | | > | | > | |
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It could be something in the alternator itself, I just got rid of the same problem. Changed alternators because it failed, not because of the noise. Also installed a solid state regulator and fixed a corroded connection in the wire to B+. Sometimes corroded connections will act as a 1/2 wave rectifier and cause interference.
Are you using resistance spark plug wires?
Hope this helps
Pete
--


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I suspected the alternator at first...so we tested. disconnected it and pulled the belt...still noisy!! its GOT to be in the ignition.
the plug wires make me wonder...is there such thing as "resistor plug wires"?? I know he's running fresh resistor plugs...but the wires are oldish (but not failing, with the water test passing ok)
I wonder if a fresh set of resistor plug wires will help? I keep coming back to the capacitor in the distributor...is it not for noise suppression too?? could it be bad?? customer tells me that when his original alternator failed, the factory radio started buzzing insanely...replaced the alternator with a fresh one, and ever since then the truck screws with the tv....
thoughts?
b

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