F350 with radio static/noise

George by Geneva, NY · Sep 10, 2020

Got a 94 F350 460gas. When the engine is running there is static/howl in the radio, worse in AM. I took belt that drives alternator off, did not unhook electrical connections, and it still does it. Alt is a replacement item, problem existed, I think before, maybe not as bad, long time ago so memory fuzzy and seldom use the truck. With engine off, radio plays ok. Any ideas? Some body out here had same problem? OEM radio. Ignition wire problem?

RayP(MI) · Sep 10, 2020

Very likely an ignition wire problem. Usually a buzzy disturbance. Check all ignition wires for tight connection at plugs and distributor as a first attempt to repair. Does the truck throw any codes, like cylinder misfire? Alternator disturbance typically shows itself as a whine.

guido · Sep 10, 2020

Hello George,

Check the plug wires at night. With the engine running, see if there is any sparks to ground.
Also check that all spark side of the ignition wires, are firmly seated to the plugs,

Guido.

spacecadet9 · Sep 10, 2020

Try unplugging the antenna at the radio, if the noise is still there something is coming through the electrical (conducted). If it's gone it's a radiated noise. Noise conducted through the power line sometimes can be lessened with an inline (power line) filter. Either a feed through capacitor or a ferrite choke. Radiated noise could be hash from something arcing or a computer (doubtful on an 94). I use to use a small handheld radio and move it around in the engine compartment. When the noise got louder I was closer the the origin.

Does you're interference change with engine speed?

chvet73 · Sep 10, 2020

I’m with Guido on this. About 30 years ago I had a ‘73 Corvette that I restored. Early on I put on Accel plug wires. Car had a miss that I couldn’t trace. One night I pulled into the garage and popped the hood before I turned on the garage lights. The plug wire looked like a light show. I never suspected them as they were only a few months old and Accel was supposed to be a good product. Needless to say I never bought another Accel product. And the miss was cured with MSD wires. So it’s amazing what bad Plug wires can cause.

Steve@Advance · Sep 10, 2020

I don't think it will be ignition. Ignition is usually crackling, popping, you can the bad wire or wires each time that cylinder fires.

Does the pitch change with the engine speed? If so, I would suspect something associated with the electronics of the engine.

If it remains a constant regardless of engine speed, suspect electric motor static, the fuel pump, AC blower, etc. Try turning everything off, see if it changes.

And it could be the antenna, or the radio itself. Maybe try a different radio, they plug and play, easy switch out.

F350 with radio static/noise

George by Geneva, NY

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RayP(MI)

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guido

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spacecadet9

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chvet73

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Steve@Advance

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