Engine runs rough after installing sub/amp

newsboy86

Member
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2002 Mazda Protege5
Since installing my system in March my engine runs rough anytime there is a load on the engine. Such as whenever the amp is on, or even if the amp is off but the a/c is on. The engine bogs down in every gear at any engine speed. When a/c and amp are both off the engine runs smooth. My amp runs 425w rms- I don't have a capacitor installed. My local car audio shop said I need an additional battery specifically made for audio systems, and that a capacitor wont help. Any thoughts/opinions/solutions? Has anyone else had this problem, whether with a Protege or otherwise?
 
Since installing my system in March my engine runs rough anytime there is a load on the engine. Such as whenever the amp is on, or even if the amp is off but the a/c is on. The engine bogs down in every gear at any engine speed. When a/c and amp are both off the engine runs smooth. My amp runs 425w rms- I don't have a capacitor installed. My local car audio shop said I need an additional battery specifically made for audio systems, and that a capacitor wont help. Any thoughts/opinions/solutions? Has anyone else had this problem, whether with a Protege or otherwise?


Does not seem like its your audio setup if you car can't handle the A/C alone (are you 100% sure the amp is off - lots of aftermarket amps are turned on anytime the power to the car is on, not just when the head unit is on).
 
Does not seem like its your audio setup if you car can't handle the A/C alone (are you 100% sure the amp is off - lots of aftermarket amps are turned on anytime the power to the car is on, not just when the head unit is on).

I will pull the power fuse and drive around for a day or two and see if there is any difference.

I also forgot to mention that my sub also randomly gets louder and softer for no apparent reason. I need to double check all my connections but I think its related to the power problem. When my engine is running rough it feels as though the spark plugs are missing from insufficient amperage
 
The sub getting louder randomly could be because your RCA wires are too close to your power wire. I'm not sure about the rough engine part though =\
 
Take the car down to your local autozone, advance auto, etc.. and have them perform a load test. They usually do this for free and will be able to tell you the condition of your battery and alternator. It sounds as though your alternator might be on its way out.
 
I don't know how I didn't think to have advance test my output for free lol thanks!
Driving with the fuse out was no different than fuse in regardless of what else was on or off.
The intermittent sub volume was due to a weak RCA connection.

Anyone know what the stock alternator puts out? I know my alternator was replaced by the previous owner but I don't know what brand or output it is
 
man i have the same thing and i have a cap and all that good stuff. my bro has a system battery and cap and circuit breakers and such and his does the same stuff on his toyota. idk the cause but i think im gonna just rebuild my alternator and upgrade it and see what happens. lemme know if you find anything out!

oh and i should mention. ive had numerous testing done such has load tests and so on by all different shops and stuff and my alternator and battery test perfect every time :/
 
for 450 watts you dont need another alternator.
The only tme I had trouble was with over 1500 watts rms at idle.
While driving it should not even be noticable.
I would have the alternator checked as its not likley that its too low of output just that its dying.

The other possiblity is that when the power wire was installed the terminals on the battery have gunk on them that are stop electriity from flowing and the alternator is really cranking to compensate.

I would disconnect the positive and negative battery termals and make sure nothing on them, or clean them if there is.

Also you may have a failing main ground wire from the batter to the chassis of the car.
If it is really corroded and nasty that may be your problem.
 
I'm going to check my alternator output hopefully tomorrow- my dad had a clamp-on ammeter that I borrowed.
There's no gunk on the battery terminals- I have a new Optima yellow-top battery in there and a Tsunami Audio positive terminal.
I am pretty sure my negative cable is in good condition as well as the negative terminal, but I will double check.
 
Finally got around to getting my alternator checked- it's not putting out enough amperage or voltage. Time for a new one!
 
Finally got around to getting my alternator checked- it's not putting out enough amperage or voltage. Time for a new one!

lol after reading the first post i knew this would be the outcome (new alternator). To help with the load in the future after the alternator, i'd suggest getting yourself a grounding kit for the engine. make your own or buy one. i've made my own, and so have a few other members, so if you have any questions feel free to PM me.
 

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