Ignitioin noise in car radio

I bought a set of sparkplug wires for my V6 3.0L 1995 Lebaron, and I had only installed 3 of them. I was trying to listen to an AM station
when I was a little out of range, and I heard the squeal of the engine, with the frequency getting higher as I went faster. I have a stock Chrysler AM/FM Cassette from about 1995. I had replaced the rotor and cap, but not any plugs yet.
These are Duralast wires, 30 dollars for a set of 6, NOT the cheapest that Advance Auto Parts had. Admittedly, I mostly listen to strong stations I have set my buttons for, but when traveling, I scan the dial, and I can't remember hearing this squeal for decades.
Are these wires defective and I should return them? Are they too cheap and I should just figure I wouldn't get good sound on these weak stations anyhow, and tolerate the squealing when I travel?
I plan to keep the car 3 to 5 more years, but I don't drive that much and these are probably going to be my last set of wires on this car.
Thanks
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wrote:

Why didn't you replace the whole set??

Stock Chrysler radios from the '80s on weren't what I'd call very good, but if adding 3 new plug wires made ignition noise worse, obviously you bought a cheap set. Duralast is a brand name for crap sold by big cheapo chains like AutoBone, Advance and others. I use only Belden wire sets and have had zero leakage or RFI problems with them for years.

Are you sure you don't have an open capacitor in the alternator's stator circuit? Many people confuse spark noise with alternator "squeal" and changing plugs/plug wires won't do a thing about a leaky alternator circuit. I believe there's a .01 ΅F capacitor somewhere in the alternator's stator circuit.

You need to answer if the problem got worse with the new 3 wires, or was bad previously. "Squeal" that's heard mostly on AM reception, not the "popping" that changes frequency with engine speed, is usually alternator RFI caused by the slip rings.
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wrote:

Oh, forgot that. Because you have to remove the air cleaner bracket, I think, to get to the other three, and I haven't had time.

I've bought crap sets before though, and never had noise in my radio.

No, not sure at all, except that I didn't notice this noise before. I think I should do some more tests, like using the scan button more and seeing how many weak stations cause this noise. I could even go back to where I was and try it there and near there. (about 10 miles away, but a place I don't normally go.)

Hmmm. This noise is a combination of the two. It's squeal that changes frequency wth engine speed. A fairly high frequency tone, myabe C above middle C (880 cps?) at 20mph, that increases as I accelerated, an octave or more.
I guess on a 6-cyl engine at 1000 rpm, that's about 3000 ignitions per minute. But the fequency of the sound was only about 1000 cps. I wonder what that means.
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wrote:

No, Middle C is 261.2 Hz. A above Middle C is 440 Hz, which is International Concert Pitch. Thus, your tone would be up around A above Concert Pitch. Never screw with a music major on stuff like this.

Ignition noise sounds more like a "buzz" or "popping." A "squeal" is almost always caused by arcing from alternator slip rings and diode switching in the alternator. The basic ripple of a 3 phase alternator being rectified could be around 1 KHz, though, so I suspect that your filter capacitor in the alternator stator circuit is shot. As I've said before, Chrysler radios, at least the ones I've seen since the '80s, are generally pretty bad anyway. With AM pretty much being a wasteland occupied by the Mexicans and the right wing fruitcakes, there's "nothing to see here," as Frank Drebin would say...with a bullhorn. Still a good source for all-news stations in major markets, though, although CBS is now screwing that up, as well. The only thing that MAY save the MW band is HD-Radio, which is now starting to roll out. Completely incompatible with conventional heterodyne radios, though.
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wrote:

Oh, yeah. I remember now.

Well, if I'd known you were reading, I wouldn't have tried this!

This is good. That means the wires didn't make things worse, and that means the wires are good enough for me.
I'll still check out the weak stations, and go to that other neighborhood if necessary (don't see how it could be necessary), but if it is the alternator filter, that's ok. I'm sure it didn't just happened and this is the first time it has bothered me.

I listen to the Latin stations sometimes, but the right wingers on the radio really are fruitcakes. It's amazing.
On this occasion, an AM station changed formats and now it's all talk, but with only female hosts, liberal, conservative, and even Laura Shlesinger, who is in a category all her own (30% very good advice, 30% average, and 40% terrible some of it enough to ruin a decent marriage.) That station is what I was trying to hear and I was only a quarter mile farther from town than my ex-girlfiend, who listens to it occasionally with no trouble. I didn't remmeber to check the radio today.

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mm wrote:

Trolling are we?
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
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wrote:

Maybe...maybe not. Later, higher voltage ignition systems require better dielectric and special plug and coil end boots (along with silicone dielectric grease) to prevent arcing. But from your description, however, I'm leaning more toward the alternator as the source.

Bear in mind that most OEM Chrysler (and everyone else, for that matter) AM sections are generally pretty bad, and have low sensitivity/selectivity. The one in my M-body would pick up nothing BUT alternator squeal unless there was a 50KW station to which it was tuned. Further up the dial in the "local" 1 KW station territory, it was hard to avoid having the IF stage swamped by alternator noise when driving in and out of obstructed areas. Going to a better radio instantly cured that problem. I also put an external "hash" filter on the battery input the original radio and there was no help...the RFI generated by the alternator's slip rings and diodes was enough to screw up the front end on that one. A look inside the radio told the tale...a DIN-sized aluminum box with only one little board in it!

As HD-Radio increases its presence, the right wingers will go away, as they will be priced out of the market. Already, Flush Limpdick and Sean Insanity are disappearing in some major markets (source: Arbitron) due to poor ratings, and the only reason they're there at all along with Air America is that air time on AM stations these days is dirt cheap and they're able to survive by attracting super-skinflint advertisers. Once wider appeal formats show up on HD-R (and its tag-along, vestigial AM counterpart), ad card prices will rise along with ratings, national ad accounts will seek wider coverage, will drive HD-R ad card prices up, and the "yakkers" be forced out. Despite all the hubris from right wing loonies, talk radio of ANY stripe has never been a big money maker for broadcasters at all. Even "all news" makes more bucks, and that ain't much. The biggest money makers on AM right now are the latin stations hands down, even though they typically have "regional" (mid-band) frequency assignments and limited coverage.
From the looks of things so far, the stations that have cut their analog bandwidth to 6 KHz and have installed HD-R modulators are simply simulcasting their AM program on HD-R, and once there are enough receivers out there, the MW band will go back to music and thus their ad cards will be competitive price wise with FM, perhaps higher in metropolitan areas where wide coverage doesn't matter. It doesn't appear that broadcasters will support two program streams...one for conventional AM and one for HD-R, although that is certainly technically feasible. Political shifts in Washington (the FCC) may have something to say about that later on. Right now, the FCC is simply a lap dog of the broadcast industry, but things are changing, as November will show.
The problem here, of course, is that you need a completely different receiver to decode HD-R signals, just like you do with Sat Rad, which uses a similar modulation scheme. Look for HD-R MW receivers to start appearing in new cars probably in the '08 model year, and I sort of expect Daimler Chrysler to be the first, like they were with the failed AM Stereo mess. HD-R "add on" receivers, which simply remodulate the decoded HD-R to an unused FM slot, are out there now, but aren't very good. Analog/sideband AM will still be available as well, but don't look for there to be much performance there, making "DXing" (listening to "skip") nigh impossible in the car, which was a big fave of mine to do in my cars on long night drives years back. As with HD-TV, signal coverage area is effectively cut in about half...digital doesn't "travel well," and won't do "skip" at all due to synchronization issues. With AM, although there is impulse noise and adjacent and "skip" channel interference, you can at least get an intelligible program, although degraded. With digital, once the bit stream loses sync, it just goes "bye bye."
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All true, but once you listen to or watch HD for an extended period of time, you are hooked. You can't go back. I've now got an HDTV at home and an HD radio in my Dakota, and analog has become just plain unacceptable. It's like going back to b&w from color, or back to VHS from DVD.
The other cool thing about HD on FM (like HDTV) is that stations can simulcast up to two additional discreet stations on the same frequency along with their primary. So in effect, we can potentially have triple the number of stations on HD FM than we do on analog FM. Since there are currently very few HD radio listeners, the HD-2 and HD-3 channels most stations broadcast have no commercials. If the format is good, these are HD radio's current gems.
Regards, Joe
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>> With AM, although there is impulse noise

But because digital uses heavy forward error correction, it can work at a signal-to-noise ratio so horrible that if you switched over to AM at the same signal-to-noise ratio, you couldn't even tell there was a channel *trying* to get through. It would sound like a dead station.
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Very true...until it loses sync. Then it's over for awhile. Different decoders handle resync differently, just like CD and DVD players. In the end, HD-R will prevail, due to its inherent frequency resue capability AND its elimination of impulse noise, truncated frequency response and other ills of old-time analog AM. However, remember you're trading one set of distortion parameters for another. Like mp3s, HD-R radio has its own set of annoying distortions.
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Hey Joe...what make of receiver are you using now?
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wrote:

home

triple

I just bought a JVC KD-HDR1 for my Dakota Club Cab a few weeks ago. Aside from a few minor quirks, I like it a lot. Crutchfield had it for $200, free shipping, no sales tax, free antenna and dash adapters. I don't know that I would've paid the full $300, but I couldn't resist it for $200. AFAIK, the sale is still going on.
I'm running it through an old Sony XM404EQ (45wRMS/ch x 4) with a pair of Polk 6-1/2 components in front and Infinity 6-1/2 components in rear. Except for a slight lack of bottom end (no subwoofer yet), the sound is nothing short of fabulous.
Regards, Joe
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Cheap wires don't cut it any more & can in strange situations can cause check engine lights. Check & make sure it has the correct spark plugs. Spend the extra money & getthe OEM wires
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mm wrote:

You say you hear a "squeal" in the radio. That's not ignition- ignition noise is more like a "buzz". A squealing, whistling, or whining sound that varies with engine speed is usually caused by the fact that the alternator has "ripple" on its DC output. A capacitor on the output of the alternator helps suppress the noise, but an inductor and capacitor on the power line to the radio will pretty much remove it. They sell these pre-packages as "noise suppressors" at car stereo stores and (at least they used to) at Radio Shack.
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Rat Shack has gotten out of the car audio biz entirely due to high return rates and lousy product quality of their Chinese imports, not to mention being run out of the market by schlock merchants like Wally-Fart. They used to sell a cheesy little L-C filter board that would do a little filtering, but usually a savvy tech can build a much better one himself. I generally use a 10 ΅F electrolytic capacitor shunted to ground fed by a series 10 mH choke coil I hand wound from just plain 18 AWG wire wrapped around a soft iron core fed through a 1N4003 diode. The diode provides isolation from the rest of the electrical system to prevent the cap from discharging through everything else on the load side of the ignition switch after shutdown. However, the diode will drop the forward voltage .7 volts, so that has to be taken into consideration as well. Since most Chryslers seem to run at a float voltage of 15.0, it's not a problem at all, although it'll materially cut amplifier capacity slightly.
I know the stock AM/FM radio in my M-body had horrid power filtering inside, and aside from being AM stereo capable (big deal...who broadcasts THAT anymore?) was a pretty crappy radio in general. Ditto the speaker compliment, which I upgraded substantially. I did note a lot of alternator "squeal" on AM in that unit, but the replacement Alpine has none, due to better power filtration. I also remember that the "squeal" dissapated greatly when I turned the slip rings and installed new brushes. The OP might also want to replace that .01 ΅F cap in the stator circuit on his '95, as that will help quite a bit.
Chrysler Corporation was the last domestic OEM customer for loudspeakers made by Jensen before they folded and the name was sold to the Japs. 4" X 6" speakers used by the ton by Chrysler cost about 25’ apiece and performed as such. Although the M-body only has cutouts in the rear shelf for 4" X 6"s, there's enough room to hog out a proper 6" X 9" hole to mount good drivers. My M-body has JBLs all around and rivals any OEM new audio system.
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DeserTBoB wrote:

Which matters not, because they sold noise suppressors FOR YEARS after they got out of the stereo business. They started out as an electronics COMPONENT store anyway, and still have some in the back if you walk past all the cellular phone crap they have in the front.
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mm wrote:

You seem to be unsure if the new wires are truly to blame. That being the case, rather than chase your tail, it seems to me the immediate experiment would be to put the old wires back and confirm for sure that the same problem wasn't there with them under pretty much the same reception conditions. That at least would preclude 50% of the what-if'ing that your doing now. That part seems kind of obvious (to me).
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
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wrote:

Tbat's a good idea. Thanks. Today I worked on the motorcycle and tomorrow it is supposed to rain (but yesterday it was supposed to rain today), so I'll try it. I think I'll try it one wire at a time.

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