rpm goes up and down when ever i turn my headlights on - Honda-Tech

rpm goes up and down when ever i turn my headlights on

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Old 09-13-2008, 09:18 PM   #1
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Default rpm goes up and down when ever i turn my headlights on

so i have jdm front that i didnt install (low inc. installed it) but whenever i put my headlights on (either the first click or second) my rpms go down just a tad and then up again like as if i put my ac on and then when i turn my lights off they go up and then down to the regular idle

i think it might be that, because my lights are drawing from the battery, its affects my rpm

has anyone come across this? is this bad for my engine? how do i fix it?

thanx for any help!
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Old 09-14-2008, 01:23 AM   #2
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Default Re: rpm goes up and down when ever i turn my headlights on (DBeight)

How long has it been happening? My alternator died when something similar happened to me...it lasted about 45 minutes then my car died. I would use the turn signal while changing lanes and my rpm guage would drop to 0 then back up.
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Old 09-14-2008, 01:45 AM   #3
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Default Re: rpm goes up and down when ever i turn my headlights on (IAM)

Well the rpm drop is caused by your alternator increasing its load on the engine.

The alternator is a controlled voltage generator when a increased demand for power is needed there is a magnetic coil in the alternator that is energized. The greater the demand the greater the magnet is energized. Thus creating more power for you to use. Your headlights draw a relatively lower amount of power and shouldnt be causing ur rpms to drop like that. You may want to try other assesories and see if they have the same affect on the rpms. If so your alternator is getting weak and as dbeight said its prolly gonna crap out on you soon.
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Old 09-14-2008, 05:55 AM   #4
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Default Re: rpm goes up and down when ever i turn my headlights on (DBeight)

There is an electric load detector that will increase the RPM when a load is detected. The RPM should only increase to about 1000 RPM.
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