Engine Noise

[Hybrid13 10+ year member]

Ok I have read all kinds of threads on engine whining and still cant figure this out. I will try to be descriptive as possible.

I have a 2007 Mitsubishi Galant the specific one I have did not come with a factory amp but there is a wire for one under the driver side dash with a 40 amp fuse in the fuse box. I hooked a wire to it and ran it down the center of the car under the carpet to the amp inside the trunk. I did the same with the remote wire from the head unit. The ground is ran to a bolt underneath the back seat. This amp is for my two 6x9s in the trunk. I unhooked the speaker wire from the 6x9s and ran them to the amp high input then out the amp back to the 6x9s. Now I have engine noise in the 6x9s.

I have troubleshooted all kinds of things and this is what I have found. I have unplugged the speaker wires that run from the head unit to the high input of the amp. The amp is still powered and the 6x9s are still hooked to the output of the amp. The engine noise is gone now.

It seems to me that the noise is coming from the speaker wires that run from the head unit to the amp, so I suspected that the head unit was injecting the noise on the speaker wires. I hooked up the speaker wires back to the amp high input but left them unhooked from the head unit and I have the noise again. So it cant be the head unit. What gives???

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[Hybrid13 10+ year member]

anybody please?

 

[smoka 10+ year member]

It seems to me that the noise is coming from the speaker wires that run from the head unit to the amp, so I suspected that the head unit was injecting the noise on the speaker wires.

Yes, the noise usually comes from the signal wires between the deck and the amp. Though its hard to say which side is the problem.

The first thing is to make sure you have good grounds at the head unit and also at the amp. Make sure the headunit is grounded to the factory harness AND that its grounded to the frame of the car. Do you have a volt meter handy? Its hard to tell if a ground is good without one.

I'm not sure if it would work, but you could try using a line-output-converter and ground the shields of the rca's. But its hard to say if it would help until you can meter your grounds.

 

[Hybrid13 10+ year member]

yes my ground is good. but the head unit is not even hooked up and i have the noise. its basically just a wire running from the trunk to the dash nothing is hooked to it. so it must be just picking up the noise by itself

 

[Horsemanwill 10+ year member]

let me see if i read this right you got your power from the fuse box of the car?

you have the hu speaker wire disconnected

and you still have noise?

try to run power from a diff source and see wat happens

 

[Hybrid13 10+ year member]

The wire that im getting power from was made for an amp (i didnt know if you caught that or not) but ill try hooking it straight to the battery. I have the speaker wire disconnected from the head unit and from the high input on the amp, everything else is hooked up and I have no noise, but the second I touch the speaker wire to the high input I have noise (keep in mind its still disconnected from the head unit).

I suspected that the way the speaker wire were running were picking up interference so I decided to run a temp/test speaker wire (my trunk has fold down seats) I connected it to the amp and tossed to the front and it picked up the noise to. Also I can touch the high input and through my body it gets the noise. Another thing I tried (which probably wasn't good to do) was I hooked the positive speaker wire to the high input of the amp and the negative to the ground of the amp and the noise went away. I dunno I'm stumped it's like my car is just radiating this noise that the speaker wires are picking up.