factory 351 75 falcon. start it up and volt meter reads 14 volts, turn headlights on and voltage quickly drops , to 10 volts after about 5 minutes. what should I look for? it has a new 530 cca battery
franc123,
Jan 9, 2:17am
This is when its idling? What is it doing at say 2000rpm?
tmenz,
Jan 9, 3:14am
A new battery should be at least 12V even when idling - if the battery is fully charged then I'd start by checking the integrity of the battery cables and their connections - at both ends. Next would be the alternator performance - as above, rev it a little and check that the lights brighten and the volts rise.
ceebee2,
Jan 9, 4:35am
Def faulty voltage reg or blown battery warning lamp. Does it illuminate when key is on with no engine start?
It should charge a min. of 12.5v plus fully loaded at idle.
paul861,
Jan 9, 7:20am
it took slightly longer for voltage to drop while driving
paul861,
Jan 9, 7:26am
yes ,all warning lights work as they should. puts out 14 + volts at idle until I turn lights on. measure with a multi meter as well as dash volt meter.
thanks for every ones input , will get reg checked
snoopy221,
Jan 9, 7:41am
End of the day the ole coon alt ain't so great in the way of amperage output. Been there done that-tip watch the ole wiper speed with the stereo and everything on. Not the silliest of things to upgrade-even moreso if it's an auto as cruisin wit da sounds in da wet can . Lead to a bigger alternator.
franc123,
Jan 9, 7:43am
I know its been said already but have a good check of all the connections associated with the battery and alternator, and the ground cable to the engine block etc, corrosion inside terminals or cables or otherwise bad connections where they attach can be responsible for such problems, as these heat up, resistance builds and you get voltage drops. If I remember right those cars have external regulators? if you have the Gregorys manual for the XA/XB it does give a test procedure for testing the reg if it looks like it might be faulty, been too long since I've touched one to remember how to do it.
snoopy221,
Jan 9, 7:50am
been too long since I've touched one to remember how to do it.
Famous qoute bra. lol They were only like 28 35 amps or so chuck a decent stereo in an auto and cruise in the rain with the heater and demister and wipers and sounds
And.
franc123,
Jan 9, 7:54am
And. it still could be the regulator, alternator OR a poor connection, hence da need ta isalaate. Could be meesta bosch or meesta autolite regulater given da finger. Kapeesh?
tony9,
Feb 23, 4:12pm
If the battery is really at 10 volts then it is stuffed, at least one cell is dead.
Even if it was new, discharging it to anything below 12 Volts will stuff a modern car battery in no time.
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