On my 92 Civic 5spd it usually runs at 12v and jumps to 14v after startup or if enough accessories are on or when you hit 40mph. So now a few times the voltages changed to 10v with the jump to 12v. Like the regulator is confused. I can get it back to normal by just turning off the car and restarting. Today I even shut it off while coasting and just turned the key back on and bumped the clutch. Went right back to the normal voltages. It hasn't changed the voltage range while running yet, just seems to startup wrong when this happens. Anyone else ever seen this? Is this the regulator or alternator about to fail? I've never had a car b4 like the Civic that steps down the alternator voltage when not needed and steps it up at a predetermined mph speed.

Thanks,

BD

 

the regulator is controlled by the ELD. this is normal, aggravating as hell, but normal.

 

I've had the car for years and the voltages always switched between 12 & 14v.
This 10 - 12v switching is a new thing and I can't believe it's normal.
When it's at 10v I'm sure the battery is discharging and that can't be right.

BD

 

how old is your battery?

 

As JSP suggested, probalby the battery, rest voltages with no load on a good battery sitting for 12 hours after a full charge should be 12.5 or higher minimum. A freshly charged battery with no load should be in the 14.2 to 14.8 max.
Fan belt may need ajustment, battery terminals clean ? jiggle the ecu plugs. Ground straps clean and tight ? rust on connections can give wierd problems. Also check the connector on the alternator itself, most are in a place where they get wet regularly and the connector pins may be corroded or loose.


Modified by itsmejto at 7:53 AM 5/31/2008