I recently fixed the wiring hack job from someone trying to install a aftermarket deck. I can now listen to it with minimal static. I added a ground from the factory amp to the body and another one from the back of the factory deck to the body. I can now listen to the radio with zero static with the ignition in the first and accessory position. Still have the static or alternator whine while the engine is running though.

So add a ground from the battery negative to the body and one to the engine? I recently replaced the serpentine belt and ran the engine with the belt off, the static was still there.

 

Are you using the factory amp? I recently overhauled the audio system in my disco, installing a pioneer deck and bypassing the main amp up front under the passenger glove box. I did not use any other items, like the line output converter that crutchfield said I would need. I also used the factory sub amp in the tailgate which is intact with new subs. With this setup, and no added grounds or anything else changed, I have no noticeable static even when the system is turned up very loud. Definitely impressed for this old car, way better sounding than my f150. The factory amp (before I bypassed it) caused unbearable static and terrible quality.

 

Check with a multimeter your added grounds to the battery to see if it properly grounded.
unplug your radio antennae lead to see if you still have noise.
Try another connector cable from the factory amp to the radio and see if you still have noise.

 

Yes I'm using the factory amp and radio. It actually sounds pretty good. I did check my grounds with my meter and they are grounded. They have the same voltage as the battery going from battery positive to my added grounds. Can I install a new RCA cable to the amp and radio? That's worth a try if it's possible to install a different cable than the stock one.

 

What I did to test my amp was followed another article on this site which described how to bypass the amp, and used short wires to basically jump the connections without actually cutting anything, and running the (i believe 4) new wires temporarily to the radio to test it, which fixed my problem right away. might be worth a shot if you cant figure it out, I dont think you need the amp anyways with a new higher powered head unit. Keep in mind that I am no expert, this is just what my problem was in my 96 and thats how I solved it. good luck!

 

I'm still using the factory amp and radio but may swap out the factory radio if the amp is causing the noise.

 

Sorry about that I misunderstood, I thought you were using an aftermarket headunit

 

If you have static (and your radio and amp are OK) then it is either poor grounding, alternator, fuel injectors, or automatic transmission solenoids 99.997% of the time. Assuming that you get this all the time even with the serpentine belt off (no alternator running?) while idling in Park (or neutral if a manual transmission), that rules out the alternator and transmission solenoids, so hunt for poor grounds first by using a jumper cable from your stereo power ground connection right back to the negative (ground) terminal on the battery post. If that does not solve the problem, a more sophisticated approach is to use an oscilloscope to look for interference from likely fuel injectors. The Pulse Width Modulated commands (on-off varying duration signals) from the ECU to the fuel injectors cause a lot of RF noise and subsequent degradation of signal. A long shot is anything else electrical that rotates or turns off and on running... like a fuel pump maybe... I hope this helps a bit, am sure others will chime in...

 

Ok perfect thank you. I've been meaning to start in the engine bay and clean all the ground connections anyway. Yes it has static all the time when the engine is running, nothing with the key in the first 2 positions. The louder a turn the radio up the less I hear the static but that's not always a good thing.

@enb54, you're saying pull the radio out while it's on and the engine is running, ground the radio and run a jumper wire to each ground to see if I can eliminate the static?

 

DO NOT pull out the radio while the machine is running. Just run a separate ground from the radio to a known good ground (like the negative terminal of the battery) and then start the car, turn on the radio, and see if that helps or even cures the problem. If it does, then investigate further to find the location of the bad ground. Sometimes people replace radio interference (suppressor) spark plug wires with wire ones, and that will also sometimes cause RF interference problems.