Radio Noise Suppression
12-06-2016, 06:54 PM
#41
What do you mean by entire shielding, just the metal cover that was over the original distributor, I have that off right now... doh.
did you do something special to shield the wires other than the cover? sorry sort of new to this stuff.
I tried a filter on the constant battery wire as I thought that is the one it uses for the amp/speakers.
I thought the ignition one just tells it to turn on, but you are saying put it on the ignition wire.. interesting will give both a go and see what happens.
did you do something special to shield the wires other than the cover? sorry sort of new to this stuff.
I tried a filter on the constant battery wire as I thought that is the one it uses for the amp/speakers.
I thought the ignition one just tells it to turn on, but you are saying put it on the ignition wire.. interesting will give both a go and see what happens.
Last edited by Ali Vette; 12-06-2016 at 06:59 PM.
12-06-2016, 07:10 PM
#42
Melting Slicks
Thread Starter
Don't worry about that Ali!Not only is the chrome "Box" over the Distributor needed, but the curved channel Shielding for the Sparkplug Wires going down from the Box, next to the Firewall on each engine side, are needed too. Plug Wires running over the Valve Covers are DEATH for a radio in these cars.
Steve
12-07-2016, 12:32 AM
#43
Team Owner
Just reading this thread and you indicate that the 'frequency' of the noise does not change with engine RPM. That does NOT sound like an RF noise problem. Ignition RF noise does vary with rpm...directly.
If you have an original Delco radio head, and it has not been reconditioned within the last 10 years (or ever), your problem is likely to be some defunct capacitors in the radio circuitry. Those things dry out/go bad over years of use/heating/cooling and need to be replaced. When they fail, the signal is lost and/or gets noisy...with a 'white noise' that doesn't vary with rpm.
Don't know that this is your problem. But it doesn't sound like ignition noise.
If you have an original Delco radio head, and it has not been reconditioned within the last 10 years (or ever), your problem is likely to be some defunct capacitors in the radio circuitry. Those things dry out/go bad over years of use/heating/cooling and need to be replaced. When they fail, the signal is lost and/or gets noisy...with a 'white noise' that doesn't vary with rpm.
Don't know that this is your problem. But it doesn't sound like ignition noise.
12-07-2016, 04:10 PM
#44
Hey Cavu2u:
I was reading back through this thread and feeling the pain all over again from my experience last month or two.
My new-installed RetroSound head unit started the "cutting in and out" habit only when the engine was running.
I was never getting any ignition whine that was RPM related, just the in and out of the overall sound, and no matter what the input was: AM/FM, AUX, USB, or Bluetooth.
I was also finding that I could tie the phenomenon to when I was getting "airborne" voltage interference that I could pick up with my digital multi-meter, usually anywhere around my ignition system underhood, and even sometimes in the passenger compartment near the radio - but only when the engine was running.
Turn the radio on with engine off (in IGN or ACC modes) and it played fine, as well as having my multi-meter show a constant 12V at the hot leads.
Turn the engine over, and the first few seconds she played fine, and the meter was reading as normal (~14.5V), but as soon as the meter started jumping around (anywhere between 12 and 18V very erratically), the sound started its cutting in and out routine.
I ended up installing several choke filters on the power input and USB cable to the radio. And also applied some foil backed Dynamat to the dash/heater plenum behind the radio. That seemed to calm things down on the radio (about 95% clean playing now).
I also replaced a ground cable from the starter bracket to the frame, which the PO had cut clean off - likely to clear the headers he had installed. That may or may not have helped the condition, but was a good thing to fix either way.
I should state, that I installed a new HEI Distributor prior to the new stereo, as well as new Moroso 8.5mm wires and some nice chrome billet wire organizer clips (the free-floating kind, not the bolt-down type), and new plugs too.
Strangest thing when I first started detecting the erratic voltage readings when probing the meter to the Alternator for +, and then to any ground - but even more so, when I removed the probes and was getting the same crazy readings from anywhere in the air around the engine compartment.
Just a lot of electrical interference in the air around the wires - but no real clue what I did to get it to stop!!
I was reading back through this thread and feeling the pain all over again from my experience last month or two.
My new-installed RetroSound head unit started the "cutting in and out" habit only when the engine was running.
I was never getting any ignition whine that was RPM related, just the in and out of the overall sound, and no matter what the input was: AM/FM, AUX, USB, or Bluetooth.
I was also finding that I could tie the phenomenon to when I was getting "airborne" voltage interference that I could pick up with my digital multi-meter, usually anywhere around my ignition system underhood, and even sometimes in the passenger compartment near the radio - but only when the engine was running.
Turn the radio on with engine off (in IGN or ACC modes) and it played fine, as well as having my multi-meter show a constant 12V at the hot leads.
Turn the engine over, and the first few seconds she played fine, and the meter was reading as normal (~14.5V), but as soon as the meter started jumping around (anywhere between 12 and 18V very erratically), the sound started its cutting in and out routine.
I ended up installing several choke filters on the power input and USB cable to the radio. And also applied some foil backed Dynamat to the dash/heater plenum behind the radio. That seemed to calm things down on the radio (about 95% clean playing now).
I also replaced a ground cable from the starter bracket to the frame, which the PO had cut clean off - likely to clear the headers he had installed. That may or may not have helped the condition, but was a good thing to fix either way.
I should state, that I installed a new HEI Distributor prior to the new stereo, as well as new Moroso 8.5mm wires and some nice chrome billet wire organizer clips (the free-floating kind, not the bolt-down type), and new plugs too.
Strangest thing when I first started detecting the erratic voltage readings when probing the meter to the Alternator for +, and then to any ground - but even more so, when I removed the probes and was getting the same crazy readings from anywhere in the air around the engine compartment.
Just a lot of electrical interference in the air around the wires - but no real clue what I did to get it to stop!!
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Torqued Off (12-08-2016)
12-07-2016, 05:06 PM
#46
thanks for the suggestions, mine is an aftermarket pioneer single din.
I do think it has something to do with the ignition, it does vary a little bit with rpm but at idle I can sort of hear it cut in and out with the cylinders firing at times lol.
The V8 does sound great but I do like a little music from time to time, even though I can hardly hear it over the side pipes its nice to have. If I had known it would be such a pain I might have skipped over the whole stereo thing but I already put 2 new speakers in the kick panels and a sub woofer in the rear jack compartment.. when the engine is off it sounds awesome!! just need it to work with the engine on now. will grab the shielding and give that a try.
anyone ever tried to install a thin metal plate onto the inside of the firewall and ground the thing, kinda like a firewall RF shield. I heard about people using foil but does foil really work well enough? some thin sheet metal won't weigh much and might do a better job I am thinking but rather not resort to that yet.
I do think it has something to do with the ignition, it does vary a little bit with rpm but at idle I can sort of hear it cut in and out with the cylinders firing at times lol.
The V8 does sound great but I do like a little music from time to time, even though I can hardly hear it over the side pipes its nice to have. If I had known it would be such a pain I might have skipped over the whole stereo thing but I already put 2 new speakers in the kick panels and a sub woofer in the rear jack compartment.. when the engine is off it sounds awesome!! just need it to work with the engine on now. will grab the shielding and give that a try.
anyone ever tried to install a thin metal plate onto the inside of the firewall and ground the thing, kinda like a firewall RF shield. I heard about people using foil but does foil really work well enough? some thin sheet metal won't weigh much and might do a better job I am thinking but rather not resort to that yet.
Last edited by Ali Vette; 12-07-2016 at 05:07 PM.
12-08-2016, 04:11 PM
#47
Race Director
I had a friend who had an old crappy cassett deck that picked up static. We used freezer tin foil grounded. Freezer tin foil is thicker. Ran it along the firewall and hump under the carpet. It helped. I also ran the feed directly from the battery on top of the hump. (both wires)
I have also put one of those toster size capacitors on a unit, with an uneven cassett speed - that has helped - they are used on high power amps to even the amperage draw when the bass is heavy. He was running the stock alt and it probally had a hard time keeping up.
Be careful when running the speaker wires they can act as an "antenna" and add static / feedback.
I have also put one of those toster size capacitors on a unit, with an uneven cassett speed - that has helped - they are used on high power amps to even the amperage draw when the bass is heavy. He was running the stock alt and it probally had a hard time keeping up.
Be careful when running the speaker wires they can act as an "antenna" and add static / feedback.
Last edited by BLUE1972; 12-08-2016 at 11:45 PM. Reason: spell