Hi. My alternator light stays on even after replacing both the alternator and the regulator. I measured the voltage of the battery with a voltmeter and it tests at 12.75 volts with the ignition off and 13.8 volts with the engine idling. With the engine cold, it idles at about 800 rpm. After the engine warms up, it idles at 2000 rpm. Could this be a short to the automatic choke? Any other ideas? Thanks very much in advance!

 

what is your car? may as well put that info in your signature so everyone knows what ur talkin about.

 

Perhaps there's a reset procedure?

 

Sorry about that- My car is an '81 Accord 5 speed. I forgot to mention that my alternator light didn't come on 'til a month after I switched out the alternator and regulator. Thanks!

 

I see .... please put the car info in your signature .... eliminates the not knowing the car issue

Unfortunately, your car is older than almost anything that I've worked on, so I can't offer much help .... one of our techs will offer some advice I'm sure; just give it a little time.

 

why did you change it in the first place? it's possible the alternator/regulator is a bad egg.

i'm not positive, but i believe there are 3 idle adjustment screws on your engine. one on the driver side, pass side and firewall side of the carb to adjust no load idle, cold start idle, load idle and a/c idle. do you feel comfortable turning mysterious adjustment screws near your carb?

 

A schematic will help you understand this...but the batt light works by way of 12v + 12v= 0volts, no voltage DIFFERENCE across the light bulb and it shuts off. And one leg of that circuit does go to the choke heater coil, and by way of your saying the choke plate is not opening and causing high idle.........
Time for a schematic and point to point wire testing.

 

chk the wiring harness,, I have seen a few of these ( well many years ago ) the electrical connector will come apart inside the connector plug ,I believe it was the white wire ,,( haven't done of of these for over 20 years ,,( man i am getting old ) , you can see some burnt marks ( melting plastic) on the outside,,
if that is the issue all you got to do is to cut the wires on both sides of the connector plug and resplice them together with eletrical connectors,,