How to test a voltage regulator

[Drake]

Hi, I'm a new member and I have a question. I have a 69 F250 Ranger with a 460. Yesterday went to start the thing and my starter kept cranking. Checked my solenoid connections and tried it again. This time the starter dissengaged but when I went to shut the engine off it kept running. unpluged ignition wire from solenoid truck shut off. I replaced the solenoid and that problem is fixed. Now my problem is I'm only getting 9.6 volts to the coil. When I rev the engine a bit I can get a few more volts. Does this sound like my voltage regulator is no good? How do you test one?

Any advice would be appreciated.

Thanks.

[fordman]

with regular points your truck will have a resistor wire in it. so it doesn't need a full 12 volts going to the coil. only the resisted amount of power to drive the points. if you had electronic ignition you would have a full 12 volts going to the coil. and the resistor would be unhooked. if you have more volts to points it would burn them up real fast. if you have less volts gong to electronic ignition it wont start or if it did it wouldn't run right probably.

the voltage regulator is only to tell the alternator to charge the battery. as it senses the difference in the battery vs what the alternator is charging or the truck is using. i do not know how to home test it. i just take them to the parts stores and let them test them for free.

[fitzwell]

Disconnect the voltage regulator , jump the "A" terminal to the "F" terrminal & start the truck... alternator should go full output. If it does, the regulator might be suspect. If not, check the wiring, or the alternator itself.

[Drake]

Thanks for your replies. The charging system seems to work good. I just thought maybe the lower volts going to the coil could be due to the regulator going bad, but I guess it doesn't have anything to do with that. The ignition system is electronic so I'll have to check that the resistor is unplugged. The guy I bought the truck from a few years back had swapped the motor out among other things so I'm finding a kinds of surprises. Thanks again.

[Thunderfoot]

Just to add... if you have a voltage gauge/meter check the battery voltage with the engine off and it should be around at least 12.2 to 12.5 then start the engine and the voltage at the battery should be around 13.5 - 14. if the regulator and alternator are working. Use the test fitswell said to confirm alternator is good when trouble shooting if the regulator or alternator is the problem after checking the voltage output I mentioned above and finding a no change or low output.

[390bump]

I agree with posts above but wanted to add that what's neat about the original/early MECHANICAL voltage regulators is that you can adjust them to give you higher or lower outputs! It is a relay that "floats" between open and closed. By bending the contacts you can make it either open or close longer which changes the voltage output. Can't do that with the solid state unit!