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86 Corolla Ground



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Hey there i got an 86 corolla 4 door liftback for free lol it runs great but im going to be installing a system into it does anyone know where a good ground is, I have already installed the system. but everytime i load a cd i can hear distortion come from the subs also whenever i put the blinker on i hear a pop sorta like when you shut off the sub its wierd it happens quite often. i tried 2 different spots the(the seat mounting and in the back hatch) i get the same sound from both spots. I also tried new rca jacks aswell. Im really stumped on this

Thanks for your help

May not just be the ground - you may also have a noisy source (battery / alternator). You could try running some filters inline with the sub to cut down on the noise. Might also help to make sure that the car's electrical system is in good shape. If the battery is a little weak, or the voltage regulator isn't doing a very good job - then there is not a whole lot you can do. Given you have a car that sis 21 years old - the original chassis grounds are probably not in the best shape. Check all the connections from the battery back to the amp/headunit. To easily check if the car is at fault or if you have a bad connections somewhere - run the audio system with the car off. Then run it with the car idling and again with a little higher rpms. If there is a significant change there, ie. no to little noise with car off, noise starts with the car idling and gets worse with more revs - then you have a noisy electrical system.

yah i just bought a new battery and alternator for it, there is no difference in the sound when the car is on and off but it seems like everytime i hit a button a pop comes from the amp ie turning on the lights turning on the heater turning on the signals

Hmm - gets noisy regardless if the car is running or not. Not a good sign. Combined with the "popping" noises you hear when you add any other electrical load, sure sounds like a ground loop issue. Ground loops introduce a humming, buzzing, or whistling noise heard through you audio system. If you have access to a decent voltmeter - measure the voltage between the ground point for the amp and another chassi ground point in several areas, ie. if amp is currently grounded to a bolt in the trunk, check for any voltage (on the order of millivolts or volts) between that ground point and say - some bare metal somewhere else in the trunk. If you have a significant amount of voltage - then you have a ground loop somewhere.

Note that is most cases, there is no "absolute" ground, as there will be a certain amount of resistance to electrical current between all grounding points. The resistance can change with humidity, temperature, equipment, and current battery/electrical loads. Resistance can always allow an electrical voltage to exist across it when there is any current flowing between those grounding points (even very low resistances, most ground loop noises are in the low millivolt range - not much needed to cause problems).

Without tearing everything apart to check for ground loops, you can help cut down the noise by running some capacitors inline with the signal cable's ground. One common way people do this is to ground some shielded cable at the source, to chassis ground - then run some capacitors (possibly a few in parallel to handle more current) to the shield ground and run that to chassis ground. This will help filter out some the high frequency noise that you might pickup from grounding loop issues.

thanks alot for your help i guess ill do the resistor thing, can you please show me a diagram of what you mean?

Simple filtering capacitor inline with the source. Let's see if this helps (These are relating to your RCA cables, as one example):

Source ----------------------------------------> Amp

(+) Source (signal) --------------------------> (+) Amp (signal)

(-) Source (ground) --> Chassis ground | (-) Amp (ground) -->Capacitor (note: polarity) --> Chassis Ground

Basically you wire a capacitor inline to the amp's signal ground. Lots of ways to do it- may take some experimenting to see where the filter will do the most good and what values you should use. Just look up more info on RC (resistor-capacitor) and LC (coil or inductor-capacitor) cirsuits. Lots of cool stuff you can do with these discrete components.

i cleaned up the battery ground and it helped a bit, but it still has a slight pop only when the car is on when it is off i can hear the loading of the disc, its not nearly as bad but still is annoying could it be my deck or amp too>

Hey there i got an 86 corolla 4 door liftback for free lol it runs great but im going to be installing a system into it does anyone know where a good ground is, I have already installed the system. but everytime i load a cd i can hear distortion come from the subs also whenever i put the blinker on i hear a pop sorta like when you shut off the sub its wierd it happens quite often. i tried 2 different spots the(the seat mounting and in the back hatch) i get the same sound from both spots. I also tried new rca jacks aswell. Im really stumped on this

Thanks for your help

To find a good ground you could use a multimeter and check various bolts near your connection point.

 

 

ive got a bad cd player ground, that is the problem. does anyone know how to go inside and fix this?

ive got a bad cd player ground, that is the problem. does anyone know how to go inside and fix this?

You mean open up the CD player and repair a bad ground inside it?

 

 

You are all missing the problem unfortunately.

Clearly joeschmo has run his power and audio wires side by side to the amp. This is what causes distortion and clicking and other mysterious electrical problems, especially popping from the subs. It's unfortunate that you bought a new alternator and battery to solve this problem unless you already needed them.

Run the power wires (positive battery connection and the remote turn on wire for the amp) down the battery side of the car to the amp.

Run the audio cables down the opposite side of the car to the amp. This should solve your problem. try to make sure they dont crossover at all for clearest sound.

Also, if you are looking for a good ground, use a bolt holding the rear seat in place. If you connect it to a body pannel you will get an annoying shock every time you close your car door after a ride. For the radios ground, you should use the original, but if your making a new one, make sure you sand the paint off of where your grounding it to, if you dont the ground will not work well and the paint will end up burning.

Let us know if that solves the problem.

You are all missing the problem unfortunately.

Clearly joeschmo has run his power and audio wires side by side to the amp. This is what causes distortion and clicking and other mysterious electrical problems, especially popping from the subs. It's unfortunate that you bought a new alternator and battery to solve this problem unless you already needed them.

Run the power wires (positive battery connection and the remote turn on wire for the amp) down the battery side of the car to the amp.

Run the audio cables down the opposite side of the car to the amp. This should solve your problem. try to make sure they dont crossover at all for clearest sound.

Also, if you are looking for a good ground, use a bolt holding the rear seat in place. If you connect it to a body pannel you will get an annoying shock every time you close your car door after a ride. For the radios ground, you should use the original, but if your making a new one, make sure you sand the paint off of where your grounding it to, if you dont the ground will not work well and the paint will end up burning.

Let us know if that solves the problem.

Sounds like good advice. The interference between the wires would be eliminated by routing them differently.

 

 

i know about the wire thing i never ran them in the same place its actually the preout grounds in the deck, so i did something on caraudio.com i ground the preamp outputs on the chassis of the deck and it solved the problem the ground look fix and it worked on it so w/e its all good, and thanks alot for ur help