Voltage reading at idle
Thread Starter
Race Director
Joined: Oct 2000
Posts: 17,102
Likes: 7
From: Fair Oaks, OK
Voltage reading at idle
When my car idles right at or just below 700 rpm, the voltage on my guage drops to 13 and the lights go dim. I have a new battery, and have replaced the voltage regulator in the alternator.
My car idles really smooth at 700, and I don't want to speed up the idle unless I absolutely have to.
So do I need a better alternator or what? Smaller pulley maybe?
My car idles really smooth at 700, and I don't want to speed up the idle unless I absolutely have to.
So do I need a better alternator or what? Smaller pulley maybe?
Melting Slicks
Joined: Jun 2001
Posts: 2,340
Likes: 2
From: Moro IL
Re: Voltage reading at idle (Simon Alexander)
Alternators are normally rated for a certain amount of amperage at a certain RPM. What's your base factory idle supposed to be set at? If your base idle is too low in other words the alternator isn't spinning fast enough it may not be producing enough to keep up with demand. Your basic choices as I see it in this matter are a higher output alternator that can produce enough voltage at that low RPM, smaller alternator pulley to speed up the alternator you already have, or bump the idle up. One thing I'd do before I'd change anything is to check your amperage output on the current alternator making sure it's not weak.
:cheers:
Pat Kunz
:cheers:
Pat Kunz
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: Voltage reading at idle (Simon Alexander)
the only clue as to what year car you have is in your statement of changing the internal regulator IN the alt for your car....so that means you have a two wire with spade terminals inline with each other, the later electronic 2 wire alternator....
so with that symptom, make sure the 'bat, alt' whatever light is in the circuit...and you should see 12 volts or more at each terminal when operating...
it should go to charge upon startup, and stay there, without blipping the throttle....if not, that idiot light may be burnt out....
or possibly the 'sense' wire, to the most clockwise terminal viewed from the back....
GENE
so with that symptom, make sure the 'bat, alt' whatever light is in the circuit...and you should see 12 volts or more at each terminal when operating...
it should go to charge upon startup, and stay there, without blipping the throttle....if not, that idiot light may be burnt out....
or possibly the 'sense' wire, to the most clockwise terminal viewed from the back....
GENE
