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Posted by: retrofit Jul 11 2007, 11:17 PM

I Know there are some audio wizards at this site and could use some help.
The 914 I have no problems with. It's my '95 Chev PU. Have too much static on AM stations. Noise is also rpm related. Like alternator whine. FM is fine. Radio /CD is a Pioneer.
Local car audio shops really don't want to work on the problem.
Called Pioneer tech support and they suggested checking the ground.
Looks like I have to fend for myself
Going to pull out the radiio/cd and one at a time:
1. Check ground. Move ground to something like chassis or stiffening bars in dash
2. Run new power lead from battery to radio with fuse near radio. Try to get clean power.
3. Have alternator bench tested? Diodes?
4. Check antenna lead from radio to antenna.
5. Check for corrosion where antenna attaches to body.
Anything else?
Do noise filters work? May try one as last resort.
Ironic that my '74 with an old radio gets clean and clear signals while '95 PU with newer state of the art radio is giving me a headache!

Posted by: dlo914 Jul 12 2007, 02:47 AM

try going w/ a resistor spark plug.

Posted by: retrofit Jul 12 2007, 01:06 PM

Forgot to mention that. I do have R plugs.
Any other ideas???

Posted by: skline Jul 12 2007, 03:25 PM

I know you said you checked the antenna lead from the mast to the radio, but perhaps you should check it again, on the 89 to 98 chevy trucks, they had a 2 piece lead from the mast to the radio. The split was behind the glovebox in the cowl. The connection there was almost always crappy and poorly grounded causing all kinds of radio problems. If you really want to eliminate them, replace the antenna with an aftermarket one with a single lead going to the radio.

Posted by: 914nerd Jul 12 2007, 03:34 PM

Better EM shilded spark plug wires
Maybe?

Posted by: retrofit Jul 12 2007, 04:45 PM

Went to MSD wires. Was part of a tuneup. Helped a bit. With the static RPM related I keep thinking alternator(?)

Posted by: 914nerd Jul 12 2007, 06:10 PM

You can always try by building a faraday cage for your alternator and seeing if that helps reduce the static

Posted by: tyler Jul 13 2007, 08:47 AM

Can't you pull the belt from the alternator and try it?

Went to MSD wires. Was part of a tuneup. Helped a bit. With the static RPM related I keep thinking alternator(?)
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Posted by: 914nerd Jul 13 2007, 09:02 AM

You could just disconnect the alternator, but it's so much less fun

Basically, start going through the ignition system and shielding things (or disconnecting them) and see if it helps