Slant Six Forum
https://www.slantsix.org/forum/

alternator diagnostics help, broken down on side of road
https://www.slantsix.org/forum/viewtopic.php?t=25937		 Page 1 of 1
Author:  Jon [ Tue Nov 20, 2007 7:12 am ]
Post subject:  alternator diagnostics help, broken down on side of road
hello,

i've got a stock 67 valiant with the slant 6.

about 2 weeks ago, i put in a new battery after the auto parts store tested the old one and found that it was bad.

this morning, as i was driving, i noticed the car wasn't running well, and the turn signals weren't flashing, which reminded me of when i had the bad battery.

almost got home, then it stalled. i pulled into a driveway, and tried starting...just clicking. called friend to the rescue.

i took out the battery, which is charging now. i'm going to put the battery back in in a few hours, and hopefully limp home.

i am hoping for some diagnostic help. how can i see if it is the alternator that needs replacing now? i've been trying to search the forums, and now am wondering if the voltage regulator could be the problem. i'm pretty handy, but inexperienced in electrical/charging problems.

i've got a multimeter, and AM PREPARED TO USE IT!! hehe

thank you for any assistance you can give.

sincerely,
jon
Author:  SlantSixDan [ Tue Nov 20, 2007 8:00 am ]
Post subject: 
Sounds like your charging system isn't working. You'll want to check all the connections to see that they're clean, tight, and free of corrosion. There's charging system diagnostic information (and parts advice) in this post. Have you got a factory(!) service manual for your car? If not, you should definitely get one ASAP, see this post. For now, you can download a free wiring diagram for your '67 here.
Author:  Jon [ Tue Nov 20, 2007 8:39 am ]
Post subject:  thanks dan
i really appreciate the help.

are the terminals on the alternator and regulator generally marked?

im still charging the battery and am going to take it back to the car in an hour or so.

while i was waiting for my friend, i looked at the alternator, with the thought of having to replace it. there were 3 wires, one thicker than the other two. here is a quote from the post you referred me to:

"To test for this, disconnect the wire from the "FLD" terminal on the alternator. Carefully run a jumper wire from the "BAT" terminal (alternator output stud) to the alternator's "FLD" terminal — if you are working with a '70-up "dual field" alternator, you need to ground the alternator's other field terminal"

im a little nervous about running jumper wires between terminals. does the wire need to be heavy gauge? how do i tell if my alternater is dual field? the car is 67, but i am not sure if the engine/alternator is older or newer than 1970.

sorry for sounding like an amatuer...but i am an amatuer!

thanks,
jon
Author:  SlantSixDan [ Tue Nov 20, 2007 9:01 am ]
Post subject:  Re: thanks dan
Quote:
i really appreciate the help. are the terminals on the alternator and regulator generally marked?
Often they are. The original 1967 regulator would have only two terminals. One marked "IGN" (it's a ring terminal with a screw holding it on) and one marked "FLD" (it's a 1/4" spade terminal, from which the wire can simply be pulled off and snapped back on). The original 1967 alternator would have had only two wires going to it. One connected to the threaded stud pointing rearward near the top of the rear housing — that's the B+ (or "BAT", or output) terminal with the thick wire. The other connected near the middle of the rear housing, marked "FLD", another 1/4" spade terminal just like on the "FLD" terminal of the regulator. That is, needless to say, the field terminal.

1970+ regulators have a unitised triangular plastic/rubber push-on connector secured with a spring steel clip. 1970+ alternators have three wires: The thick BAT/B+/output wire/post in the same location as described above, and two FLD wires/terminals as described above. This information should help you determine if somebody has swapped a '70+ alternator or a '70+ alternator and regulator into your '67.

When using a '70+ alternator (with two field terminals) on a car with a '69-down regulator, one of the alternator's two field terminals must be connected to ground via a wire. It does not matter which of the two field terminals is grounded.

It is also possible the third wire you're seeing is a ground wire, in which case it might connect to a "GRD" hole on the rear of the alternator housing or to another attachment point on the housing or bracket.
Quote:
im a little nervous about running jumper wires between terminals. does the wire need to be heavy gauge?
Not really, no. 16ga will be plenty.
Quote:
how do i tell if my alternater is dual field?
See above.
Quote:
sorry for sounding like an amatuer...but i am an amatuer!
Too bad you're not an ammeter...that would make it easier to diagnose the situation! :mrgreen:
Page 1 of 1 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/