you may need to rev the motor higher to get the alternator to register them remanufactor type alternators sometimes do that the exciter in it is set at a higher rpm than idle give it a rev and watch your volt meter jump up to 14 volts :yes:
thanks . I wish that was the problem but its not. its a regular three wire alternator not a 1 wire. I looked back at a couple of my log files and even revving to 2000rpms, the voltage does not come up.
It's not working correctly. Each cell of the battery will make around 2.2 volts X 6 cells. The battery should be at or near 13.2 volts the best I remember. If the alternator doesn't produce a minimum voltage greater than the battery has in it it will not charge the battery.
its a basic 12si alternator. I dont think it requires 12 volt input but I might be wrong. my undertanding was that it is self grounded, the main post goes to the charging stud, one small wire also goes to the charging stud to sense the voltage, and a final wire goes to the dash warning light. I have everything hooked up except that wire that goes to the dash.
I have three meters. a voltmeter gauge, a multimeter, and the built in gauge in megasquirt. they show almost the same thing
Some alternators needs to know when the car is started. It usually gets the signal from the idiot light circuit. There are other ways of doing it, but it is the best way for internally regualted altenators.
you are very right. I found this and it basically explains what you said, that the alternator needs the field current to initially energize. lol
for some reason I thought the field output was just a lamp output to the dash. lol
Field current supply is provided from two different sources - from the alternator itself, via the diode trio, and from the battery, via the alternator warning lamp. When you first get in the car and turn the key on, the engine is not running and the alternator is not spinning. At this time, the voltage/current source for the field current is from the battery, through the ignition switch, and through the warning lamp. After the engine is started, and the alternator is up to speed, the output of the diode trio is fed back to the regulator, and serves as a source of current for the field current.
I think it is working now, because the ignition seems to be firing better(engine also running a lot leaner), and the car wont switch off when I turn off the ignition.
wtf?
someone tell me if this is wired incorrectly:
the ignition is wired to the battery through a relay that is activated by the ACC connection on the fuse box.
it should stop firing when I turn the key off right? well, the car wouldnt stop until I pulled the lead going to the distributor off the relay. whoa, scary.
any ideas? I would have thought maybe it was dieseling from being too lean, but it died instantly when I disconnected the hei, making me think the relay was somehow not switching off with the key switch when the alternator is energized.
I needed to add a diode when I had the problem of the engine not shutting off with the ignition key. I had MSD ignition and it was in the trouble shooting instructions for it.
well it looks like the sense wire and diode did the trick
the sense wire to energize the alternator and get it started,
the diode to allow the engine to stop when I turn off the key.
gauge was bouncing between 12.5 and 14.2 at a very low rpm, between 400-700 rpms, and megasquirt says I was at 13.1 volts for the 10 seconds it ran. I call this a pass.
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