Low Idle

Ok, fit me sub in today, and i have a bit of a problem
when the bass drops really low, my idle drops down to around 300 till the bass stops, then goes back up again
any clues?
crap battery?
shagged altanator?
Thing is, the battery is about 2 months old and aint ever had problems till i fit the sub
think i might have to get a power cap then


yeah ure just using too much power, mine does the same thing. let me know how much the cap helps the situation. Ive been wanting one for monthes but ive just had to settle with turning the volume down because i cant afford one.
Good thinking batman
i showed one of my mates and he said the idle doesn't actully drop, its juts the rev counter, i haven't looked myself yet tho
i'll give it ago after me dinner and let you know
i'll probably end up getting a cap anyway tho


The answer

Your friend is probably right. The revs should not drop greatly because the engine would compensate for any drops in revs. The extra draw of current from the amplifier does not sap power from the engine, just puts more strain on the alternator and makes the engine work a little harder. As the revs drop below the normal idle, the ECU lets a little more air and a bit more fuel into the engine, bringing it back up

As for the rev counter, with the Nissan, like many modern cars, the rev counter is not controlled by the engine. The ECU uses the sensors around the system, i.e. crankshaft sensor and camshaft sensor to determine the speed of the engine. The ECU then sends a voltage to the rev counter and displays the value on the gauge. If the ECU is sapped of power because of the extra drain on the battery, it will give false readings.

If your car's idle dropped to 300 it would stall.

what you running and what you playing ???????????

firstly if you're playing sound check cd's or real sub bass tune like fuel cd's a power cap will make it worse as these are for punchy tunes they save the extra energy between beats and give a kick out with the next beat but for long bass notes the power cap gets hungry and will draw power away from the amp so depends on what you're into

ive still standard battery etc im running two amps a single channel kicker kx400*1 for my 15" comp sub and an alpine v12mrv-f407 for my 4 6x9s
don't have any probs
I have a standard battery, and all i am running is a 500w sub with a 500w amp (i aint running the full 500w through it btw)


I also had this problem with my car, I had my system running through a 1000watt Alpine amp and when my lights started dimming when I was driving and my engine was sitting @3K RPM (which actually led to me needing a new battery the next day) I knew I would have to do something, I have since resorted to running my 6*9's through a 150w amp and my sub through a 400w amp.

At least now my car doesn't seem to die when I stop at traffic lights :D



have any of you checked to make sure the alternator belt aint a touch slack etc.. ?
i have a volt meter on my car & when i crank up the bass it does dip but never much below 14v
Yeh, i got a volt meter on mine
when the cars running, it sits just under 14volts, and when the bass drops, it dont move it just stays there
belt aint loose or anything either
its a strange one
Top Bottom