At idle what should the voltage in the car drop to? Mine will be at 13.8V when I'm driving and fall to 12.3V and by the time the light turns green it’s down to 11.2V.

I know it will drop when the alternators slows down but should it go below 12V.

 

nobody

 

even at idle you should be around 14v [I think it's 14.something but whatever]. but that is the lowest it should be with the alternator running. may be different depending on your alternator or if you have aftermarkey pulleys, etc.

it shouldn't ever be as low as 12v. cuz that means you are running on only the battery and the alternator is doing no work [dead].

 

so maybe time for a new alternater

 

well...i would have it checked first before doing that....could be a dying battery too...did u check the water in the battery and stuff? do the little checks first

 

I had the same problem before. Come to find it was the crank pulley I had on (OEM Honda CTR race pulley). I swapped back to a stock LS unit and now the problem is gone. If I'm not mistaken the CTR pulley is not "balanced" for my LS motor setup.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NVturbo &raquo;</TD></TR><TR><TD CLASS="quote">I had the same problem before. Come to find it was the crank pulley I had on (OEM Honda CTR race pulley). I swapped back to a stock LS unit and now the problem is gone. If I'm not mistaken the CTR pulley is not "balanced" for my LS motor setup.</TD></TR></TABLE>
I am not all that savvy when it comes to Honda motors, but V8s have a harmonic balancer that is balanced for the specific motor and the crank pulley is just a pulley. but depending on the motor or if it's an "underdrive" pulley, you can be making the alternator turn at a different rate. basically, a smaller crank pulley will make your accessory pulleys turn slower. in the case of the alternator, I think this can cause the voltage to drop. same thing happens if the alt pulley is larger than stock.

15psi, do you have aftermarket pulleys or pulleys swapped from another motor? I would think this is the issue if your voltage is normal while driving [when the RPMs are up enough to make the alt produce the proper output]. ever notice [usually on an older car] that your headlights brighten up when you rev the engine and get slightly dimmer when idling? that's where I'm going with this.

 

Still, shoudn't the voltage regulator even out the peaks and valleys? I'd check your wiring, and if you aren't getting any significant voltage drops due to bad cable, I'd think about a new alt.