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Radio Noise

Discussion in 'Chevy Trucks' started by Pelican, Jul 29, 2003.

  1. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    I've got a '92 3500 with the 454. After starting, I get an electrical noise on the AM radio that lasts about 30 seconds and then clears. I never hear it again until restarting. It sounds like an electric motor is running on the truck, then cuts out. Any clues?
     
  2. wyldman

    wyldman Member
    Messages: 3,265

    Electric fuel pumps with a bad commutator will do that when they start to fail.Maybe it's the fuel pump ?

    Try turning the key to the run position,but don't start it.The fuel pump will run for a few seconds.Listen for the noise.If it goes away when the fuel pump stops,then the pump is causing the noise.You should also hear a small "click" when the pump stops.It is the relay opening.You can see if the noise corresponds with the click of the relay.
     
  3. Arc Burn

    Arc Burn PlowSite.com Addict
    Messages: 1,138

    #1 What are you doing listening to the damn AM radio
    And #2 It's probably the Republican station,can't quite make out what their saying can you?Just make something up:D Kidding kidding kidding
    Seriously though,does it do it no matter what AM station?Do you have FM,Does that do it,I've noticed a similar "whine" the few times i've had the AM on.
     
  4. wyldman

    wyldman Member
    Messages: 3,265

    It could also be the alternator.As the regulator cuts back the charge rate,the noise disappears.

    Arc - I was going to say the same thing,quit listening to AM :D
     
  5. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    You know where my radio is tuned.

    Chris, I thought it might be that too, but I never hear it again while the truck is running. Is there a special cycle the pump does at startup? I've heard that on other cars, the hum that disappears never to be heard again until the next startup. Why is this?

    I'll do your check tomorrow.
     
  6. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Chris, you and I were posting at the same time. Where do you guys think I get my ammo for squashing Liberals?;)

    Is the alternator deal a normal condition or a warning of failure?
     
  7. wyldman

    wyldman Member
    Messages: 3,265

    The pump runs for two or three seconds when you first turn the key on to prime and build pressure.You will hear it for a few secs,then a click as it and the relay shut off.You should be able to try and match the radio noise to the pump noise or relay click.

    You can also try unplugging the regulator plug on the alt,and see if it goes away.If so,it's in the alternator assy.
     
  8. Earthscapes

    Earthscapes Senior Member
    from WNY
    Messages: 577

    Pelican---- i have the same problem with my 90' every time i try to listen to a nascar race all i get is static. So now i drive the 03' when i can't be in front of a tv to watch
     
  9. BWhite

    BWhite Senior Member
    Messages: 496

    Radio

    Rush , Hannity, Savage, Severence, Howie Carr you got to love them
     
  10. wyldman

    wyldman Member
    Messages: 3,265

    Excessive radio noise from the alternator could indicate future failure,or it could just be a cheap rebuild job.Wire routing,and poor connections can also cause this.

    Any updates on the noise ? Have you been able to isolate it at least ?
     
  11. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    I haven't been in the truck since I started this thread, I've been running the 550 so much. I'll be moving it in the morning, so I can try your suggestions. Thanks!
     
  12. Arc Burn

    Arc Burn PlowSite.com Addict
    Messages: 1,138

    Never mind,turned out to be a couple Republicans is all:D Just tryin to help buddy:help: :waving:
     
  13. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Tried it today, the noise is only apparent after starting and then fades away. No noise what so ever from the fuel pump when turning on the ignition. I didn't have a chance to disconnect the regulator.
     
  14. wyldman

    wyldman Member
    Messages: 3,265

    It could be the alternator then.As the regualtor cuts in,the noise fades away.

    Unplugging the regulator would be the next step then.