Adding subwoofer caused mass misfire on all cylinders

[jp1234]

Hi everyone, I have a 2015 gt premium with 70k miles on her. A few months ago i added a subwoofer to the car and then started experiencing weird misfires. when i would go WOT from time to time it would throw a flashing CEL and the codes would be misfires on everything. I chased it down and checked just about everything in the book and couldnt fix it or find an issue. I eventually for shits and giggles disconnected the sub woofer and all the problems went away. I was wondering if anyone knew why that would cause the car to misfire and if there was a way around or to prevent it from happening. This is the sub i had put in https://www.skaraudio.com/products/sdr-1x12d2-rp-800-1d-skar4anl-cca. The way I installed it was I tapped into the rear speaker harness for the left and right speakers and used the back-up camera as my remote wire. (I also installed new kicker door speakers but haven't had an issue with those being in there.)
Any input would be great, I'm very new to the car audio scene so I'm still learning.

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[robvas]

Probably want to have a car audio shop check it out. First guess would be something like a capacitor or larger alternator is needed because you're drawing too much power

 

[jp1234]

Probably want to have a car audio shop check it out. First guess would be something like a capacitor or larger alternator is needed because you're drawing too much power

I got you, would a capacitor make it to where I wouldn't need to upgrade the alternator?

 

[robvas]

I got you, would a capacitor make it to where I wouldn't need to upgrade the alternator?

Probably want to have a car audio shop check it out.

 

[Goterr0r]

Check your battery. If its on the edge of being bad, its likely drawing just enough extra power to start jacking with the car electronics causing the misfires.

 

[Evolvd]

Are the misfires happening when the audio is off or just when your bass is hitting? What size is your amp and power/ground wires?

 

[jp1234]

Are the misfires happening when the audio is off or just when your bass is hitting? What size is your amp and power/ground wires?

it was happening even with the audio off, just at random times. 4 gauge power and ground and the amp is a single channel 800watt rms

 

[jp1234]

Check your battery. If its on the edge of being bad, its likely drawing just enough extra power to start jacking with the car electronics causing the misfires.

I did have to replace the battery right before I put in the sub, But ive checked it a couple times to see what it was resting at and it seemed okay

 

[5doorsoffury]

i would see if it happens with the amp on at low volume and if it does i would disconnect the remote since it may be tapped onto a wire that is no bueno. at least thats where i would start. if it is a current draw issue then haveing the amp at low volume would reduce the curre t draw to a minimum. the best approach is to disconnect 1 wire at a time and repeat the issue until it goes away then address that wire hookup.

 

[junits15]

something is up if its happening all the time, this isn't gonna sound like a good answer but you likely wired it wrong. Double check all of your connections, make sure that the wires you tapped into are actually what you think they are.

Easy test is to disconnect the amp and see if the problem goes away, I bet it wont.

 

[Evolvd]

it was happening even with the audio off, just at random times. 4 gauge power and ground and the amp is a single channel 800watt rms

That doesn’t make any logical sense that it would be the amp causing it then as it’s drawing no power when the audio is off. Something else is amiss.

 

[Mike Pfeifer]

The only possibility that comes to mind for me is perhaps the amp is faulty and causing RF interference that is getting into the cars other systems. I used to have a PPI PowerClass amp that was faulty, could not listen to AM with it powered up - it was essentially transmitting RF noise splatter all over the spectrum. Even if you were in another car and were near enough, AM reception was gone. It’s possible that that kind of thing could happen and interfere with other vehicle systems.

 

[Blueflash]

Did you do a BMS reset when the battery was replaced?

 

[jp1234]

Did you do a BMS reset when the battery was replaced?

I did not

 

[jp1234]

The only possibility that comes to mind for me is perhaps the amp is faulty and causing RF interference that is getting into the cars other systems. I used to have a PPI PowerClass amp that was faulty, could not listen to AM with it powered up - it was essentially transmitting RF noise splatter all over the spectrum. Even if you were in another car and were near enough, AM reception was gone. It’s possible that that kind of thing could happen and interfere with other vehicle systems.

That would be interesting, I did have another sub woofer and amp setup in the car and it did cause the same problems though

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