Wiring Cleanup and Noise Reduction

[patrickbrown]

I need to do some house cleaning of my wiring before I attempt to install my MS.

I have a 62 Falcon. It's V8 powered. I relocated the battery to the trunk. I also relocated the starter solenoid to the trunk. There is a large braided ground strap from the engine to the chassis. The battery is grounded to the chassis in the trunk. From the plus side I have a large cable going to the starter solenoid (also in the trunk). Then a large cable under the car to the starter. The main harness in the car is powered with a #8 wire from the battery to the front of the car.

Here is one of my problems. The radio sounds awful. I hear ignition and my electric fuel pump through the speakers. I know I need to get a better handle on this or the MS will not work at all.

My electric fuel pump is at the rear and is running through a Bosch relay that connects to the battery side of the starter solenoid. It is grounded to the same bolt that attached the pump to the car.

My ignition is an MSD 6AL. The heavy red wire (power) is routed to a lug at the front of the car. It is where the #8 wire terminated that I spoke of earlier. The MSD box is grounded to sheet metal near the unit.

The stereo amp power is coming off the battery side of the starter solenoid and is trunk mounted. The ground is to sheet metal near the amp.

I also have an Innovative wide band tool that is very noise sensitive. I ended up having to run a dedicated power and ground cable to the battery to get that to work properly.

Here is what I'm thinking about. Please tell me if I'm crazy or should be doing something else.

1) Run the fuel pump ground to the same ground point as the large ground cable from the battery.
2) Run the MSD ground to engine ground (braided strap from engine to chassis).
3) Run the stereo amp ground to the same ground point as the large ground cable from the battery.

Do you think this will help? I could maybe run a large #1 ground cable from the battery ground point to the engine ground. I think it might be a bit of overkill but I've seen a few threads where it was mentioned.


Thanks,

Patrick

[Matt Cramer]

That sounds like it should clean things up a bit. Also consider running a dedicated ground cable from the engine to the battery directly.

[thedge]

Make sure the ground points are clean bare metal. Wire wheel them to remove paint so the contact is metal on metal.

[Hey_Allen]

Just a thought, but when I work on bare grounds, I make sure to use a anti-oxidant paste or at least some dielectric paste to prevent rusting or corrosion of the connection.

I don't like to be reworking my ground straps when I could be working on other things, only months down the road!

[patrickbrown]

I finally finished my ground project. I purchased a ground cable kit that included 20' of 1g wire and the necessary hardware. This now goes from the battery negative directly to the engine block. I then redid the grounds for the fuel pump, stereo amp, and MSD ignition. The fuel pump and amp are grounded directly to the battery in the trunk. The MSD box goes to the engine block ground point. The engine block is also grounded to the chassis with a heavy braided strap.

This helped a lot but I still get a whine when the engine is running. I have an electric fan but it wasn't hot enough to be on so that isn't is. I think it is either the alternator or the ignition. The whine varies with engine speed. Oddly it does not get louder when the stereo is turned up. It is always at a constant volume.

Any thoughts on this? I plan to pull the alternator belt tomorrow to see that is it.