Engine Noise
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=27586
Printed Date: July 22, 2025 at 9:03 AM
Topic: Engine Noise
Posted By: Dauber
Subject: Engine Noise
Date Posted: March 02, 2004 at 3:05 PM
I got a good problem that hopefully somebody can help me out with. I have a 1985 mustang, trying to run a decent system, spent about 4 years cleaning it up, taking all the rats nest of factory wiring that came with the car, finally starting building a system in it, and bam, engine noise. Three systems ago I put a noise filter which does ignition, 12V and ground, and that got rid of my problem, back then that is. Then I decided to switch head units, add two amps and good insulated RCA's, ran away from any power wires, proper 4 gauge wires with good solid grounds, upgraded the battery, new alternator, voltage regulator(regular maintenance on old cars) and factory ground and power wires from the terminals. I have two sets of speakers in dash and door, none in rear, 2 12 inch subs, tantrum amp, alpine 4 channel, pioneer 1/2 din 8 band equalizer, pioneer head unit(DEH7500) 1/2 farad stiffening cap, JL 12 inch w 0's, and I still get the engine noise! all power is routed to the back, same with ground all to one point, tried this to see if it would eliminate noise problems, it didn't. Any input would be appreciated.
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Kyle@Audio Obsession Sound
Replies:
Posted By: forbidden
Date Posted: March 02, 2004 at 3:09 PM
I was going to guess that you might have a Pioneer head unit, is it grounded to where the amps are?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Ravendarat
Date Posted: March 02, 2004 at 3:26 PM
If I am reading your post right it suggest that you ran your deck ground the length of the car to the back of the vehicle. If you did that is definatly a problem. Every single ground in car audio should be no longer than 3 feet. very ground should also be to a clean unpainted surface, preferably with a star washer of some kind.
Posted By: Dauber
Date Posted: March 02, 2004 at 4:14 PM
For both forbidden and ravendarat, yes the deck was run to the same ground point as the amp, but either grounding it to a bare metal ground point near the deck in three different places or running it back didn't make a difference, and the ground point for the crossover underneath the deck is grounded seperate from the deck.
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Kyle@Audio Obsession Sound
Posted By: DYohn
Date Posted: March 02, 2004 at 4:25 PM
Bypass (or remove) the EQ and see if your problem goes away.
Posted By: Dauber
Date Posted: March 02, 2004 at 4:27 PM
I did that too, went away alittle bit, but noise is still there.
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Kyle@Audio Obsession Sound
Posted By: DYohn
Date Posted: March 02, 2004 at 4:39 PM
Have you set your amplifier gains properly (and the gain on the EQ if it has one)? Pioneer equipment is very noisy so you may simply be hearing the limitations of the equipment. OH WAIT, I just re-read your initial post. You say you installed a new alternator and voltage regulator. This is the most likely source for your noise if it is engine noise that began after the units were replaced. Make sure the grounding on both is solid, and you may want to replace the engine ground strap as often this corrodes and causes noise in older cars. Did you replace the spark plug wires with good quality supressor wires as well?
Posted By: Dauber
Date Posted: March 02, 2004 at 4:48 PM
Engine ground strap replaced and upgraded through and through, and I don't think that the alternator or the regulator are the source because I had the noise even before I replaced them. I know this problem is probably minor to fix, its just pinpointing the source thats taking so long. Its not really loud noise, I just hate noise.
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Kyle@Audio Obsession Sound
Posted By: forbidden
Date Posted: March 02, 2004 at 4:55 PM
Replace the head unit with another brand, see what happens. What is the resistance on the ground return? ------------- Top Secret, I can tell you but then my wife will kill me.
Posted By: DYohn
Date Posted: March 02, 2004 at 5:00 PM
Sometimes it is a very simple thing like a stray strand on a speaker wire touching ground somewhere... but these are always the hardest problems to find. Good luck!
Posted By: forbidden
Date Posted: March 02, 2004 at 5:03 PM
Brain fart, some 1985 Ford vehicles had the main power harness ran directly behind or below the radio, is this where it is in the mustang?
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Top Secret, I can tell you but then my wife will kill me.
Posted By: Dauber
Date Posted: March 02, 2004 at 5:24 PM
Battery is run on passenger side, then to driverside through the firewall to fusbox. ------------- Kyle@Audio Obsession Sound
Posted By: Dauber
Date Posted: March 02, 2004 at 5:29 PM
Question for you guys though, might it be the 4 channel amp I'm running for my mids and tweets? Its an older Alpine 3527S amp. I heard good things about these amps, but who knows.
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Kyle@Audio Obsession Sound
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