Poor Fm Reception With Ignition On

[srgilbert]

Hi,

I have a 95 LS400 with the Nakamachi head unit. WHen the ignition is on I get great reception. When the car is running only the strongest stations come in well. ANy idea what the problem could be?

Thanks!

[corndog]

Have you recently made and changes? ie: change spark plugs, or wire anything new in your car, etc.

[SKperformance]

What do you hear instead of the station?

Is it a whining noise and does it change with the engine RPM's?

[LScott400]

My '94 has what is described as a Noise Filter bolted to the driver's side coil bracket. Unsure of its role, but perhaps this is a possibility.

[srgilbert]

What do you hear instead of the station?

Is it a whining noise and does it change with the engine RPM's?

Actually I made too many changes. I replaced the antenna mast with an aftermarket one - from a truster Ebay source and replaced the head unit. This was ll do to the fact that I was having right channel drop outs for extended periods. Going back in time I had Lexus repair the head unit and amp and a year or so later the same problem came back. Through a bone yard I ordered a replacement Nalamachi head unit. With all said and done I'm not sure what is causing the problem. With the ignition on and the car running no problem with reception with the car running I loose the reception and I get some static. ANy noise I get does not vary by speed. I'm really at a loss on this one. Should I get an aftermarket antenna and plug it in to the head unit to see if that solves the problem?

Thanks!

[nc211]

I think you have one of two problems. SK will correct me if I'm wrong though, becuase he knows this stuff A LOT better than I do. I think your aftermaket antenna is a possiblity. I also think with your new head unit, and you said they did something with your amp?? It sounds like a possible cause for what is known as a "ground loop isolator". Sounds like you might have a ground problem somewhere. I think why SK asked you if it changes with rpm's is because the higher the rpm's, the faster the alternator spins, putting out more electricity. A faulty grounding can pick up that extra electricity in the form of noise and static through the speakers.