radio has engine noise/grouding issues
09-30-02, 03:55 PM
#1
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radio has engine noise/grouding issues
I've searched on the topic, probaly a groudn somewhere. Here's my setup, Sony MP3 CD Player to a 400 Watt/Channel Amp running 2 speakers and a Sub. I have a 1991 RX-7. Problem: engine whine sensitive to RPM (revs).
At first I would get this strange beat going on mixed with the music I was listening to. Turned out the radio ground wasn't grounded. (grounded /w amp ground via bolt of seat rail by trans tunnel)
Now, engine whine. It got MUCH better when I unplugged the antennae. What does this mean? I have 2 wires not plugged into anything out of the harness of the CD Player: ANT, and a remote power. I don't know what these do. Power antennae? I thought I could just use the antennae built into the windshield?
I will try grounding the RCA's. I have expensive shielded RCA's.
At first I would get this strange beat going on mixed with the music I was listening to. Turned out the radio ground wasn't grounded. (grounded /w amp ground via bolt of seat rail by trans tunnel)
Now, engine whine. It got MUCH better when I unplugged the antennae. What does this mean? I have 2 wires not plugged into anything out of the harness of the CD Player: ANT, and a remote power. I don't know what these do. Power antennae? I thought I could just use the antennae built into the windshield?
I will try grounding the RCA's. I have expensive shielded RCA's.
09-30-02, 07:57 PM
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DO NOT GROUND THE RCA's! They are floating grounds.
The head unit wire harness ground(black) should be connected to the chassis ground on the wire harness. Also, use a ground strap to ground the head unit chassis to the car chassis if recommended in the user manual.
The amp should be grounded as near to the amp as physically possible. You probably want to use at least 8 AWG with that amount of power.
Again, consult the user manuals.
Make sure your yellow head unit wire has a filter on it. I think you can also get filters for the antenna coax at a sound store.
You can use the windshield antenna only.
Wrap the end of the power antenna wire from the deck with electrical tape, and tie it up nice and neat.
Connect the remote wire, blue and white, to the remote or REM terminal of your amp.
Again, do not ground the RCA's!
Good luck and have fun.
The head unit wire harness ground(black) should be connected to the chassis ground on the wire harness. Also, use a ground strap to ground the head unit chassis to the car chassis if recommended in the user manual.
The amp should be grounded as near to the amp as physically possible. You probably want to use at least 8 AWG with that amount of power.
Again, consult the user manuals.
Make sure your yellow head unit wire has a filter on it. I think you can also get filters for the antenna coax at a sound store.
You can use the windshield antenna only.
Wrap the end of the power antenna wire from the deck with electrical tape, and tie it up nice and neat.
Connect the remote wire, blue and white, to the remote or REM terminal of your amp.
Again, do not ground the RCA's!
Good luck and have fun.
09-30-02, 08:34 PM
#3
Former Moderator. RIP Icemark.
You have a classic example of a ground loop.
You should never ever ever ever ground a amp or any other high output device like a amp to a seat bolt. You need to have a dedicated ground bolt/connection with only the ground for the amp and radio hooked to it. The holes for seat bolts, are painted when the car is made as well as the seat bolts are anodised to protect them from grounding and corrosion.
Some cheap amps will have a ground loop no matter what, since you didn't say what kinda of amp you are using its hard to tell.
When you unplugged the antenna and the sound got better, that is telling me that the deck was not grounded very well if at all. You may wish to run a 10 AWG wire from the back of the radio to the same new ground bolt you will be installing for the amp.
If you have just a crappy cheap amp and can't get rid of the ground loop any other way, you may also try a Ground Loop isolater, although with some of the bargin priced ones there will be a slight degradation of the signal.
Also... Make sure you are running the power for the amp to the battery and that power wire is fused within 12 inches of the battery. You should also replace or upgrade the ground between the engine and the car body and the battery and car body if you have not already done so. The factory ground wires on most Japanese cars are only good for about 10 years, before they start degrading.
You should never ever ever ever ground a amp or any other high output device like a amp to a seat bolt. You need to have a dedicated ground bolt/connection with only the ground for the amp and radio hooked to it. The holes for seat bolts, are painted when the car is made as well as the seat bolts are anodised to protect them from grounding and corrosion.
Some cheap amps will have a ground loop no matter what, since you didn't say what kinda of amp you are using its hard to tell.
When you unplugged the antenna and the sound got better, that is telling me that the deck was not grounded very well if at all. You may wish to run a 10 AWG wire from the back of the radio to the same new ground bolt you will be installing for the amp.
If you have just a crappy cheap amp and can't get rid of the ground loop any other way, you may also try a Ground Loop isolater, although with some of the bargin priced ones there will be a slight degradation of the signal.
Also... Make sure you are running the power for the amp to the battery and that power wire is fused within 12 inches of the battery. You should also replace or upgrade the ground between the engine and the car body and the battery and car body if you have not already done so. The factory ground wires on most Japanese cars are only good for about 10 years, before they start degrading.
Last edited by Icemark; 09-30-02 at 08:37 PM.
10-01-02, 03:57 PM
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Thanks for the advise, all.
I will try grounding the engine--it does need it.
Should I run a cable from the negative terminal to the transtunnel area to ground the stereo system from?
I saw these 'isolators' at Pep Boys that looked like metal cubes /w cooling fins and plugs. Is this usuable, or is this that ground loop isolator? I never heard of a filter for the yellow cable. What store can I get this at? Does Radio Shack carry it? would it be trashy?
Also, when I tried to ground the radio chasis or ground wire to the trans tunnel bolt it actually got more engine noise in.
Thanks for all the help. I'll let ya'll know what happens. Thanh
I will try grounding the engine--it does need it.
Should I run a cable from the negative terminal to the transtunnel area to ground the stereo system from?
I saw these 'isolators' at Pep Boys that looked like metal cubes /w cooling fins and plugs. Is this usuable, or is this that ground loop isolator? I never heard of a filter for the yellow cable. What store can I get this at? Does Radio Shack carry it? would it be trashy?
Also, when I tried to ground the radio chasis or ground wire to the trans tunnel bolt it actually got more engine noise in.
Thanks for all the help. I'll let ya'll know what happens. Thanh
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11-22-02, 12:37 AM
#8
Former Moderator. RIP Icemark.
No, you can't ground right too the battery or you will have a ground loop (the ground potential is different on path).
Again as I posted before:
That means you need to drill a hole, and mount a bolt to the body that you ground everything stereo related to.
Again as I posted before:
You need to have a dedicated ground bolt/connection with only the ground for the amp and radio hooked to it.
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