I need to know where one wire goes from the back of my alternator. It's a 1985 F-250 with a 460 engine. The plastic insulating shield on the connector of the alternator is white and the plastic shield on the wire is black. I cant tell what color the actual wire is because it's old and faded. It's a small wire about 16-18 gauge. veiwing the alternator from the rear, it's the connection on the far left. Someone mentioned to me that it might go to the electric choke...why would a wire go to the choke? Help!!

 

That sounds like the stator terminal. It's usually marked S or STA. It goes to the electric choke, because the stator signal is only hot when the engine is actually turning. You only want current going to the choke when the engine is actually turning, so it's perfect for that. The stator signal is a 12V AC signal. If your put your DC meter on it, it will show up around 7V RMS.

 

thanks for the reply. I'll pull the alternator and see if it's marked S to confirm this is the connection is for the stator. I was trying to avoid pulling since the AC bracket is a pain in the neck on this truck. I no longer have the stock holley carb and have mounted a edelbrock afb #1411. Do I just tap into the + electric choke wire when hooking it up?

How would not having this hooked up affect things? My system is not charging and I have 12.1 Vdc at the battery when engine is running and 12.3 Vdc when the engine is off. I am wondering if It may have caused my regulator or alternator to go south by running it unhooked? Of course after a while my batteries die due to no charging.

Thanks again!

Zeus

 

I checked the voltage on the wire with my Fluke 87 on dc voltage. At first, it read 7.1 then went to 7.4 v. after a few minutes, it now reads anywhere from 4.9 to 5.1 to 5.4 volts. Does that indicate that the alternator might be bad? I took it to NAPA auto parts and AutoZone and had it bench tested on their alternator machine. It failed at NAPA and passed at autozone. I dont know which one of them is right...

As far as the wire from the stator to the choke, what is the purpose of this? Is the alternator recieving power from the choke wire or is it providing power to the choke? does the alternator work without it connected?

The electric choke on my edelbrock AFB is powered by a 12vdc wire coming from Accessory on the fuze block (as recommended by edelbrock). Does this change where the stator wire should hook up to?

Thanks,

Zeus

 

This stator wire does not matter. Just get rid of it. It powered the original Ford electric choke. They hooked it up this way so the engine had to be turning for the choke to get power. GM used an oil pressure switch for the same thing.

Here is one of the senarios they were worried about;

It's cold outside, and Joe decides to listen to the radio for a few minutes before he starts the engine, and he uses the keyswitch in run instead of the "ACC" position. Well if the choke is hooked to a hot terminal with the key on, then the choke is getting power and warming up, and pulling off. Later on he decides to start the engine, but lo and behold it will not start. Why? Because the electric choke has been on and is completely pulled off, so he has no choke at all, and it will be hard to start and run rough if he does get it started.

Most people with any sense do not need all this though, so just hook your new carb choke up to a keyswitch power source. You usually have to run into the cab to get it.

Back to your problem. I first would hook everything back up, and then get your meter and see if you have battery voltage on the large "bat" terminal on the rear of the alternator. If you don't then you have fusible link burned out in this wire.

If you want to test the alternator, take the "f" wire off the back of the alternator and tape it. Then get a scrap piece of wire and hook it to the "f" terminal. Start the engine, and while you have your meter on the battery, touch the "f" wire to the battery + terminal. If the voltage junmps way up, and the alternator starts whining, then it's good.

Make sure you do that "bat" wire test first though. It's the most common problem when people work around the alternator without disconnecting the battery first.