Alternator workings / Stator wire question

[mudgepondexpress]

I just spent a few days trying to figure out a problem with the choke on my daughter's 83 Capri V6. I am hoping someone can explain what would possibly have happened.

1) Alternator died. Only 1 located in all of Spokane, Orielly's Auto Parts (groan), so I purchase it to get her back to college.
2) quick install, charging at 19.5 volts...looks like we need a voltage regulator also. So another run to the Kmart of Auto stores
3) quick install, charging is down to 14.5, all looks great, let's button it up and send her off to school.
4) won't come off high idle. Hmmm that is weird. Choke wire is hooked to the Stator post on the alternator, just like before.

So here is what I did:
1) tested voltage on stator wire while disconnected from choke thermostat: 7.0 volts DC. (that should be correct), wire to battery -
2) hook up to choke, nothing, no movement.
3) remove choke thermostat, hook up wire, 7.0 volts from thermostat to battery ground. (center lug of thermostat where the coiled wire connects)
4) Try grounding thermostat to battery, nothing happens after 5 minutes
5) try different thermostat, same thing, no movement. Worked fine before alternator problem.
6) put original thermostat back on, stator wire reads 7 volts disconnected.
7) hook wire up to thermostat, take a reading on the connection, -0- volts. remove wire, 7 volts, hook up wire -0- volts (to battery ground).
I know there is something wrong with the stator connection. Try to explain that to Orielly's! It charges so they say it is OK.
9) Go to pull and save yard, there is 1 85 thunderbird V6, I am lucky
10) Install used alternator, charges at 14.5 volts, choke works as it should connected to the stator.

How can it show charge, voltage at stator wire, then when I hook it up, nothing? If memory serves me correct, there are three poles / pickups, the three are run through a rectifier to change AC to DC voltage. The Stator is just a wire from one of these poles.

Please help me understand this. I really don't want to sit here with a $100 unreturnable paper weight. I don't care if they just exchange it, at least I would have a working spare.

Kenny

[qikgts]

I'm going to guess at a bad diode on the pair for the stator connection. Maybe do a diode test on the stator terminal comparing the known good with the bad one?

[Ethyl Cat]

Is the wire you are using Wht/Blk? According to my diagram, that wire feeds a choke relay that is hot in the run position.

It is used to close the relay contacts and supply a higher (fused) current to the choke.

Maybe current is limited to just enough for the relay pull in windings and not sufficient enough to heat the choke element?

[mudgepondexpress]

On the 83 V6, the wire is straight from the Stator post to the choke thermostat. The choke thermostat is rated at 6 volts but really any voltage works, it just takes longer to heat up.

I will check out the diode. Like I said, alternators are a little foreign to me (but not un-learnable).

Kenny

[at_the_junkyard]

I've played around with some of these choke caps before. Try measuring a resistance to ground from the choke cap + terminal to chassis/ battery.

From what I remember there is an electrical wiper assembly (wear item) inside the choke cap. A high resistance connection here can cause low or no current and won't heat up the coil spring thing to move the choke tang etc. You will still read volts from terminal to ground but have no current flow etc.

Hope that helps

[at_the_junkyard]

Ok re-read your post. Looks like you established that your choke cap is functioning with the junkyard alternator so yeah ?