Engine Interference, need Noise Suppressor

[Mopard]

I have a Alpine CDA-7894 FM/AM Cd Receiver. It has alot of engine interference, injectors, Alt. etc. Not sure what all it is. What would be the best noise suppressor to get? Also which wire should I use it one? The one that goes direstly to the battery or the one to the fuse box? Any other ideas?

Also this unit is a high power receiver that requires that one of the power wires be wired directly to the battery POS. terminal.

[riquiscott]

A noise suppressor shouldn't be necessary. Apine receivers are generally pretty good about rejecting noise, and most often, suppressors are just a band-aid to cover up other installation problems. Where do you have the receiver's ground wire connected? Are you using any external amplifiers or signal processors? If you've grounded the receiver under the dash, I suspect you probably have one or more ground loops. Try grounding the receiver directly to the negative terminal of the battery. A temporary jumper wire out the window and under the hood will work for testing purposes. Also make sure the ground wire from the battery to the chassis is connected well.

What do the noises sound like? It is a whine that varies in pitch with engine speed? Is it a constant popping/clicking? A popping/clicking that varies with engine speed? Do the turn signals cause noise?

Also, what kind of a vehicle is this in, and do you have any aftermarket electronics, such as an ignition box or special plug wires?

Scott Gardner

[Mopard]

I have the ground wire connected under the dash.
I have 2 external amps and an Alpine EQ.

I had thought about grounding it to the NEG. BAT. terminal but was not sure it was a good idea.
I also have added an extra ground wire fron the NEG. terminal to the engine head on the BAT. side,
I also have added another ground wire from the engine block to the motor mount on the passenger side.
I then removed the orignal factory ground wire from the chassie and filed all of the corrosion from all of the terminals, and where it connects to the chassie.
Last the injectors also have their separate ground wire.

The noise is a whine that varies in pitch with engine speed. It has a very, very slight constant popping/clicking. Very hard to hear, barely noticeable. It does not varie with engine speed. The turn signals cause no noise.

[MoparMarcIdaho]

If you get everything powered and grounded to the battery that should do it,but if not,radio shack has a shunt coil that should do just fine.

[tinner73]

run double shielded rca cables away from the tranny to the amps. also keep cables away from 12v wire from batt. that feeds amps.ground from amps should be as short as possible...under 18" if possible. good luck.

[tinner73]

run double shielded rca cables away from the tranny to the amps. also keep cables away from 12v wire from batt. that feeds amps.ground from amps should be as short as possible...under 18" if possible. good luck.

[riquiscott]

I would be willing to go longer than 18" on the amp ground cables, just for the sake of keeping all of the components grounded to the same spot. The best thing would be to run a long, large-gauge ground cable from the battery back to the trunk (or whereever the amps are mounted), and then use a distribution block off of that large cable to ground the head unit, amps, signal processors, CD changers, and anything else in the audio system that needs grounded. This is called a "single-point" or "star" grounding scheme, and will eliminate ground loops within your sound system. Under the hood, use a good ground between the battery and the chassis, and from the battery to the engine block, and that will eliminate the rest of your ground loops.

Scott Gardner

[Mopard]

Originally posted by MoparMarcIdaho
If you get everything powered and grounded to the battery that should do it,but if not,radio shack has a shunt coil that should do just fine.

I will try the ground wire to the bat first then I will give radioshack a try. I don't do much shopping with them. Don't know much about their products.?

[Mopard]

Originally posted by tinner73
run double shielded rca cables away from the tranny to the amps. also keep cables away from 12v wire from batt. that feeds amps.ground from amps should be as short as possible...under 18" if possible. good luck.

It has been a while since I installed the rca cables, I am not sure they are double shielded or not. They are routed away from the tranny. I did not think that would make a difference, but that is how I routed them anyway. I did try to keep the ground from the camps as short as I could. Not sure how short it is.

[Mopard]

Originally posted by riquiscott
I would be willing to go longer than 18" on the amp ground cables, just for the sake of keeping all of the components grounded to the same spot. The best thing would be to run a long, large-gauge ground cable from the battery back to the trunk (or whereever the amps are mounted), and then use a distribution block off of that large cable to ground the head unit, amps, signal processors, CD changers, and anything else in the audio system that needs grounded. This is called a "single-point" or "star" grounding scheme, and will eliminate ground loops within your sound system. Under the hood, use a good ground between the battery and the chassis, and from the battery to the engine block, and that will eliminate the rest of your ground loops.

Scott Gardner

Thje large ground wire from the bat to a distribution block is another great idea. I will try that if the ground wire from the bat. to the head unit does not work.

So it would be safe or a good idea to ground everything to do with the system to the same ground?

[Mopard]

As far as a "good ground between the battery and the chassis" is concerned, could i do this by useing a ground wire from the NEG. bat. terminal to the engine head on one side of the engine and then use another ground wire from the engine block to the motor mount on the other side of the engine like I did?