[RICH N]

My 69 nova has a am radio it sounds fine with the engine turned off but when i start the car the radio picks up a lot static ? Where should i start to look for the problem ?

 

[tony]

Are you running resistor type spark plugs...??? If so.,check (or possibly change) your plug wires.........:yes:

 

[67pete]

Power supply in line filter for the radio supply feed.

Oh, Corvettes had metal shielding for their plug wires....

 

[RICH N]

Sholud i have a resistor plug or a non resistor plug in the engine did not think that would make a differance ?

 

[tony]

Resistor type (R) if ya wanna cut down on the static....:yes:

 

[surfdog]

same issue here...

I had my 64 factory am radio upgraded with am/fm guts.

Radio is picking up ignition noise. I'm running HEI ignition.

I'll have to check my plugs as well... I believe they're parts counter Champion .

I've tried different 12v and ground sources, same problem.

I tried a Crutchfield noise filter, don't waste your $$, does not work.

Just sharing my challenges as well!

 

[Nova_Guy]

Disconnect the alternator and see if the noise goes away.

 

[surfdog]

Disconnect the alternator and see if the noise goes away.

I can remove the output wire at the alternator to do this?

 

[RICH N]

I UNPLUGED THE 2 WIRE PLUG AT THE REAR OF THE ALTERNATOR AND THE NOISE STOP,S THE RADIO SOUNDS FINE UNTIL I PLUG IT BACK IN ?

 

[firebird77clone]

you have a 'noisy' alternator.

Check with your local rewiring shop ( about every town has one ) and ask them specifically if they can fix a 'noisy' alternator.

 

[Nova_Guy]

I can remove the output wire at the alternator to do this?

Yes that will work, that will "turn off the alternator". If the sound goes away that will let you know that was the problem.

 

[Nova_Guy]

I UNPLUGED THE 2 WIRE PLUG AT THE REAR OF THE ALTERNATOR AND THE NOISE STOP,S THE RADIO SOUNDS FINE UNTIL I PLUG IT BACK IN ?

You can either swap alternators or have that one fixed on an original or restored car.

 

[Jack Burton]

Are your condensers (capacitors) hooked up? There should be one on your voltage regulator and another at your distributor or coil.

AM radios are susceptible to any electric "noise" like lightning or electric trains. Your ignition system is no different.

 

[surfdog]

Are your condensers (capacitors) hooked up? There should be one on your voltage regulator and another at your distributor or coil.

AM radios are susceptible to any electric "noise" like lightning or electric trains. Your ignition system is no different.

Still haven't pulled the alt wire to test this as a source of noise... Does an HEI have a condenser? I don't recall seeing one last time I pulled the cap. My setup is a factory regulator. I've been thinking about upgrading to a 3-wire, internally regulated. Thanks!

 

[Jack Burton]

Still haven't pulled the alt wire to test this as a source of noise... Does an HEI have a condenser? I don't recall seeing one last time I pulled the cap. My setup is a factory regulator. I've been thinking about upgrading to a 3-wire, internally regulated. Thanks!

If you didn't see one near the coil or distributor, both Mallory and MSD make noise filters. Your factory voltage regulator should have something like whats pictured below coming off the side spade and the case grounded out with the regulator chassis.

 

[Custom Jim]

Do you have a mast type antenna on the front or rear of the car ?. If so make sure the underside of the antenna is grounded well to the metal surface. If it's a front mounted antenna make sure the fender is grounded well to the firewall.

You may also have some problems with the Diodes inside the alternator.

Another thing to check is on older AM radio's there was an antenna trimmer. Basically this rotary adjustment matched up the antenna to the tuner section. To adjust it you would tune to a weak AM station up high on the dial (like 1300 or so) and then turn the trimmer screw one way or the other until the maximum volume was heard. By doing so you still have the noise but now it is more overidden by the signal. Matching up the antenna to the tuner is like on the newer systems with radio's and external amplifiers. If you have the gain on an amplifier too high you also hear things you don't want to hear like background hiss and alternator whine. By turning down an amplifier gain to properly match a radio's output the objectional noise will be lower than the music or talk you want to hear.

On a little note too on condensors (capacitors), after time, heat, and age these things become nonfunctional. Even if old ones are in place they may be shot and ineffective.

Jim

 

[surfdog]

If you didn't see one near the coil or distributor, both Mallory and MSD make noise filters. Your factory voltage regulator should have something like whats pictured below coming off the side spade and the case grounded out with the regulator chassis.

Yes, my external regulator does have a capacitor. I pulled my red/hot alternator wire off and still have radio noise. I have a GM HEI with MSD "Street Fire" wires #5551. They're for a stock HEI application and have EMI supression. My plugs are Champion Copper Plus, RJ12YC resistor. Did a new cap/rotor/wires/plugs just recently.

Pulled my antenna connector from the radio and still ignition noise.

I wonder if my capacitor needs to be replaced? And switch to different plugs? The noise source is definitely somewhere in my ignition. Thanks!

 

[Jack Burton]

Yes, my external regulator does have a capacitor. I pulled my red/hot alternator wire off and still have radio noise. I have a GM HEI with MSD "Street Fire" wires #5551. They're for a stock HEI application and have EMI supression. My plugs are Champion Copper Plus, RJ12YC resistor. Did a new cap/rotor/wires/plugs just recently.

Pulled my antenna connector from the radio and still ignition noise.

I wonder if my capacitor needs to be replaced? And switch to different plugs? The noise source is definitely somewhere in my ignition. Thanks!

Hmm, did you try double checking all the plug and coil wires to make sure they're on tight? It certainly wouldn't hurt to replace the regulator condenser like Custom Jim said..should be a $4 part. The next thing I guess would be to check the ground on your radio. Make sure the radio is grounded as close as possible..i.e. don't use the factory harness ground unless it terminates nearby.

I just saw you had the radio upgraded to AM/FM. When reassembling the radio someone might have forgotten to solder or connect all the ground points making the radio chassis an ineffective shield (or something along those lines). I'd check into that possibility as well. BTW, If you're hearing noise in FM mode, then the problem is not in your receiver but in the radios audio amplifier circuit (definitely a shielding issue).

 

[surfdog]

Hmm, did you try double checking all the plug and coil wires to make sure they're on tight? It certainly wouldn't hurt to replace the regulator condenser like Custom Jim said..should be a $4 part. The next thing I guess would be to check the ground on your radio. Make sure the radio is grounded as close as possible..i.e. don't use the factory harness ground unless it terminates nearby.

I just saw you had the radio upgraded to AM/FM. When reassembling the radio someone might have forgotten to solder or connect all the ground points making the radio chassis an ineffective shield (or something along those lines). I'd check into that possibility as well. BTW, If you're hearing noise in FM mode, then the problem is not in your receiver but in the radios audio amplifier circuit (definitely a shielding issue).

Thanks Jack, I'll check to make sure my wires are on good and tight. I suspected the radio at first and send it back for a replacement board and to confirm everything is good. Yes, I hear the static noise on AM and FM, makes no difference. With no volume I can here the noise. I'm going to replace the condenser in my HEI and voltage regulator. Hopefully this will cure it. Oh, and I have a good chassis ground near the radio. I tried moving the ground to different locations, no improvement.

 

[Jack Burton]

Thanks Jack, I'll check to make sure my wires are on good and tight. I suspected the radio at first and send it back for a replacement board and to confirm everything is good. Yes, I hear the static noise on AM and FM, makes no difference. With no volume I can here the noise. I'm going to replace the condenser in my HEI and voltage regulator. Hopefully this will cure it. Oh, and I have a good chassis ground near the radio. I tried moving the ground to different locations, no improvement.

Ahh...you're getting noise with the volume all the way down. I wish you had said that earlier. That sounds like a ground loop, i.e. more than one grounding point on the radio. Think about this for a sec...when you're volume is all the way down, the input to the audio amp is "grounded out" which ideally doesn't let anything through to the amp because there is no signal to amplify. If a ground loop is present, it acts as an antenna, picking up noise and feeding a signal into the amp through the ground. I don't know what else it would be. You might want to ask a CB or HAM guy about it.