Headlights dim and car idles at lower RPM after Sub install

[naheed24]

Hi,

I just got a 120W RMS MTX '8 Subwoofer installed in my car today. After testing I noticed that my Idle RPM has dropped and the car gets shaky when the gear is set to Drive and when stopping on a red light. Also at night the headlights and interior lights dim when the woofer hits. Is there a lot of load on the battery? Honda Civic 2012 coupe. Any suggestions?

Thanks.

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[Popwarhomie 5,000+ posts]

120 watts is hardly anything and shouldn’t have your lights dimming. I know the Honda’s like to shut off the alt to save fuel but I’m no expert on what models have that feature.

 

[CodyDaGoat]

I don't think 120 watts is going to make your headlights dim. LED headlights shouldn't dim if you upgrade to those on 120, but since you are having problems. I'd first start by checking for a bad alternator and battery to begin with.

 

[Popwarhomie 5,000+ posts]

LED headlights shouldn't dim if you upgrade to those

God no....

 

[CodyDaGoat]

God no....

It is just a suggestion to temporarily stop headlight dimming. Wasn't not trying to indicate that this would fix his problem completely

 

[Popwarhomie 5,000+ posts]

It is just a suggestion to temporarily stop headlight dimming. Wasn't not trying to indicate that this would fix his problem completely

Throwing LEDs in a housing not made for leds and blinding everyone else with glare is not a fix.

 

[CodyDaGoat]

Throwing LEDs in a housing not made for leds and blinding everyone else with glare is not a fix.

This is the number one suggestion I have heard over the years from all my local shops, and from bigger Youtubers including Exo. You are entitled to your opinion. I was just giving a suggestion. And yes, they do make bulbs for his vehicle. I'm sorry if somebodies illegal LEDs blinded you in the past and made you upset.

 

[Popwarhomie 5,000+ posts]

Thats because they are morons and don't know jack **** about lighting. I've been building projector retrofits for 9 years now. I have alot of experience with lighting. Plug and play LED/HIDs are trash. Throwing leds in your headlights is not a fix for voltage issues.

 

[Deleted member 677857]

Hi,

I just got a 120W RMS MTX '8 Subwoofer installed in my car today. After testing I noticed that my Idle RPM has dropped and the car gets shaky when the gear is set to Drive and when stopping on a red light. Also at night the headlights and interior lights dim when the woofer hits. Is there a lot of load on the battery? Honda Civic 2012 coupe. Any suggestions?

Thanks.

Did you do the installation wiring yourself? Is the lower RPM, rough idle, etc. only when the sound system is playing or all the time since the install?

 

[Timbo74]

Hi,

I just got a 120W RMS MTX '8 Subwoofer installed in my car today. After testing I noticed that my Idle RPM has dropped and the car gets shaky when the gear is set to Drive and when stopping on a red light. Also at night the headlights and interior lights dim when the woofer hits. Is there a lot of load on the battery? Honda Civic 2012 coupe. Any suggestions?

Thanks.

I would check your alt, check your battery.
As was previously stated 120w is nothing, and should not effect your electrical in the least. Even if your Honda has that fuel saver feature...this is 120w we are talking about...unless your alt isn’t running for an hour or two, it should make no difference.
The only thing I can think of, is either a bad battery, or an alt, that isn’t doing its job. But most likely a bad battery. Is your battery the original?

 

[Deleted member 677857]

I would check your alt, check your battery.
As was previously stated 120w is nothing, and should not effect your electrical in the least. Even if your Honda has that fuel saver feature...this is 120w we are talking about...unless your alt isn’t running for an hour or two, it should make no difference.
The only thing I can think of, is either a bad battery, or an alt, that isn’t doing its job. But most likely a bad battery. Is your battery the original?

A bad battery can definitely cause a heavy load on the alternator. I'm thinking if this started after the install, something is putting a serious load on electrical for the idle to drop and the car stalling in gear like that. Wiring issues or the amp itself has something wrong with it. Maybe he meant to say 1200 or worse, 12,000 watts?

 

[Boominburban]

yeah, you sure it isn't 1200 watt . As that is entirely possible for an mtx sub/system. And I could see that affecting your electrical, but not 120 watts. Just doesn't make sense unless you already had an underlying problem you weren't aware of maybe.

 

[THATpurpleKUSH 5,000+ posts]

If you add aftermarket audio to any honda made after 2000 you likely need to install an ELD bypass. The car is designed to shut off the alternator if it's not detecting a heavy load which is likely whats happening at idle. Measuring the input voltage at the amp is a step in the right direction.

 

[Deleted member 677857]

If you add aftermarket audio to any honda made after 2000 you likely need to install an ELD bypass. The car is designed to shut off the alternator if it's not detecting a heavy load which is likely whats happening at idle. Measuring the input voltage at the amp is a step in the right direction.

I agree and great advice. He needs to do that so his alternator will maintain a higher operation voltage for optimal performance of the amp, but either the load being put on the alternator is too great for it too handle is the reason with the car is idling down.shutting off. Voltage output will help the amp to operate better, but it won't solve the what seems to be an overload issue. I think whoever did the wiring may have created a problem, the amp may be defective, or the addition of the new audio was the last straw for a weak battery and alternator.

 

[Deleted member 677857]

yeah, you sure it isn't 1200 watt . As that is entirely possible for an mtx sub/system. And I could see that affecting your electrical, but not 120 watts. Just doesn't make sense unless you already had an underlying problem you weren't aware of maybe.

Would be one heck of a MTX system at 12,000 WATTS! Maybe he got a Jackhammer.