Alternator Troubles to start it charging

[dannyboy]

I have an external regulator (new) and alternator (new) If I just start the 350 it does not start charging. If I rev the motor it starts charging, sometimes when I drive and get on it and do 45mph it starts charging.
Yes have had parts checked and NAPA says they are working?
What problem do I have. It works and charges just fine as long as I remember to gun it to start it charging.
Stump the Stars??

[weq92f]

How are you determining it isn't charging? At the dash panel gauge?

Place a meter on the battery terminal with engine off. You should get 12-13+ volts. Start the engine and you should immediately see 13.8 to 14.5 volts at the battery terminals.

If, as you say, the engine is idling and you DO NOT see 13.8 to 14.5 volts at the battery, something isn't working correctly. At this point, you would rev it and then see the correct voltage range at the battery right ( as per your scenario given to us )

Try the meter test at the battery.

-klb

[rockyrivermark]

I put a new alternator on my truck last year and ditched the external voltage regulator.
Mine can be run as a 1 wire or (I think it's 3-4 wire can't remember) wire.
I ran mine as a simple 1 wire to battery. easy install but I read that it needs to get rmp over 800 or something along that rmp to trigger charging when first started. Then it will charge at idle.
to change to the 3-4 (again I can't remember which) you need to have a ignition wire going to alternator with a diode in line of it or a bulb in dash.
Google it and it will make more sense.
Mark

[swb4me]

Originally Posted by dannyboy

I have an external regulator (new) and alternator (new) If I just start the 350 it does not start charging. If I rev the motor it starts charging, sometimes when I drive and get on it and do 45mph it starts charging.
Yes have had parts checked and NAPA says they are working?
What problem do I have. It works and charges just fine as long as I remember to gun it to start it charging.
Stump the Stars??

My truck was doing the exact same thing after I replaced my alternator and external regulator. What finally fixed my was removing the ground wire near the regulator and cleaning the area under it to bare metal. That ground wire grounds the voltage regulator and the alternator. Once I hooked everything back up, it charged at idle. I hope this helps you avoid the hours I spent trying everything else.

[davepl]

Is it a one-wire alternator? They do not self-excite and the engine RPM must be "blipped" for them to start charging. It's one reason I never use them...

[VetteVet]

Originally Posted by dannyboy

I have an external regulator (new) and alternator (new) If I just start the 350 it does not start charging. If I rev the motor it starts charging, sometimes when I drive and get on it and do 45mph it starts charging.
Yes have had parts checked and NAPA says they are working?
What problem do I have. It works and charges just fine as long as I remember to gun it to start it charging.
Stump the Stars??

The stock regulator did not come modified as a one-wire alternator as far as I know. They used the SI series alternators. However anything is possible.
It would be easy to tell by just disconnecting the alternator plug and see if the alternator ever charges. If it reacts just as it is now then it is a one-wire, if not then your regulator is not sending the signal to excite the alternator circuit to charge the fields in the alternator. Your regulator may not be grounded as was stated above.

Take the alternator plug and test the white wire in the plug for 12 volts with the key on and zero volts with the key off. If you don't get anything then the external regulator is not working or it may not be getting voltage to the brown wire on the regulator plug. Test it the same way.

When you had it tested at NAPA did it start charging right off idle or did they just tell you it was good?

[dannyboy]

Ok not running or at idle a volt meter reads 13.7, while idling I rev it up and bingo to goes to 14+ volts, that's how I know its not charging.

No its not a one wire, its an external regulated alternator.

I did clean the ground connections but, thanks I have not gone back thru and made sure they are good, done with a ohms meter by the way. Good swb4me, that's what I will try. I should of already done that.
I understand the charging system "Renton VoTech 1972 Auto Electrical Course" so the tests where done with that know how behind me. Not that I have not forgotten more than I learned LOL

[RichardJ]

Ask by weq92f
>>How are you determining it isn't charging? At the dash panel gauge?<<

Answer from dannyboy
>>Ok not running or at idle a volt meter reads 13.7, while idling I rev it up and bingo to goes to 14+ volts, that's how I know its not charging.<<

???????????????

13.7 volts at idle IS CHARGING.

[mike16]

I always thought that the one disadvantage of an alternator charging system is that it does not charge at idle or at low rpm's, and you must have a full 12 volts plus comming from the battery.

maybe change the diameter of the alternator pulley

a quick way to tell if your alternator is charging is to touch the back of the alternator, where the bearing is, with a metal screwdriver. if its magnitised, the the alternator is working.

yea, check your grounds.