I have an Edlebrock carb on my 360. Been running great but recently the electric choke does not work. The truck was idling fine around 650 rpm, then all of a sudden the idle jumped to 1000 or better. I noticed that the fast idle screw was getting stuck on the cam and not droping off the cam once warm. I tested the volts to the electric choke and got nothing. So the choke is not working (that is what pulls the screw off the cam). My question is what would make the stator on the alternator stop making volts with the volts still going to charge the battery. I get 14.2 volts to the battery. Any help would be great. Also I have read in many posts about the stator being used for stock carbs, but not for aftermarket ones. Can I use the factory wiring from the stator on the alternator with my Edlebrock carb?

 

What do you have your meter set to when you're reading it? What scale? The stator is an AC signal, FYI. If you set an inexpensive meter to DC it should read around 7 volts RMS assuming you are grounding the other probe properly.

 

fmc400
thanks for the response. I checked the wire to the carb and the stator in DC, but got nothing. I also grounded the meter to the engine block and the neg battery post. I can check again in AC, but saw 0.00 in DC. Have you ever heard about the stator going bad, but the alternator still working. I am wondering if the alternator is going bad. Also what is your opinon about connecting an Edelbrock carb to the factory wire to the stator. Will it work ok.

 

I find it really odd that your alternator is obviously charging, but you don't have any signal on the stator. If the stator fails, the alternator can't work because the stator is basically half of the alternator. Try checking the signal directly on the 'S' terminal on the back of the alternator instead of the wire you have running to the carb, because it's possible just the wire is bad. If the stator doesn't have a signal, the regulator can't pull the alternator on-line and your battery won't charge.

You shouldn't have any trouble hooking the choke to the stator terminal, in fact that's how the factory did it for the stock carburetor. The Edelbrock literature does state to run it to 12 volts DC but I know people who run it to the stator without any problems. All the choke needs to do is heat up, and there is still enough DC in the signal seen on the load to do the job. Now, if you run it like this for a while and you find that the choke is taking too long to open because it's not heating up quickly enough, then you'll want to try running it to 12 volts DC. But you should be fine. I run my Edelbrock from a keyed 12 volts source, because I wanted it to be fused. That is something you might want to consider.

 

fmc400
OK today I double checked my work. I have been going off of the stator for my tests and the neg battery post. I took the wire out of the equation right away. So with the engine running, and my multi meter I measured AC on the 200 scale got nothing, then switched to DC on the 20 scale and got nothing. I tested a wall outlet and got 120 so the meter is good. I checked the battery post to post with engine running, got 14.2 volts DC. So alternator seems to be charging. So does this mean that my alternator is going bad. Is there a way that the stator post is disconnected on the alternator? My friend says I should just connect ot 12v keyed source and be done with it. If I go to keyed 12v source, where should I get the source? From the fuse panel. I don't like splicing into windsheild wipers or some other thing. Is there an extra fuse in the box? thanks for your help.

 

Go to the "I" on the starter solenoid- AKA starter relay on the innrer fender.

 

I'm really stumped as to why you're not seeing anything on the stator but the alternator apparenty is working. I'm in the process of talking to someone to see what might be up, so let me get back to you on that one.

You can definitely just run off a 12 volt keyed source, that's what I am doing. On my '79 there was a keyed source in the same connector as the stator signal in the factory harness, so I just pulled off of that. I don't happen to have the 'I' terminal on my solenoid, just the 'S'.

 

I also had an extra connector pigtailed with the electric choke connector, right above the passenger side valve cover. Definately factory whatever it went to, possibly the original idle solenoid?

Josh

 

Yeah, that's what it was on mine. It was a 2-connector pig-tail. One wire was the stator signal for the choke and the other was hot-in-run for the idle solenoid.

 

Hi jim4, I talked to someone that would know (Franklin2 in the electrical forum) and he confirmed your suspicion - it's possible for the alternator to charge without anything coming from the stator terminal and it's likely the 'S' terminal on your alternator is broken internally. Just out of curiousity, does you truck have the factory ammeter setup (D...C) guage on the dash or just an ALT light?

 

I have the guage, what is the curiosity?

If you are asking if the needle moves, on most guages is moves very, very little. I would actually make the assumption that if the needle moves a notieable amount in either direction something is wrong.

Basically it shows a slight charge, but once the lights and heater are on the needle is pretty much dead nuts center. At the battery I am still getting 13.8-14.2 volts.

Josh

 

On your setup - is there any factory wiring between the 'S' on the alternator and the 'S' on the regulator? I thought there was supposed to be, but I'm seeing conflicting explanations.

 

I do have an "S" wire, it's white with black

or it could be black with white

There is no "I" it seems coming from my voltage regulator however.

Josh

 

Ok, FMC400 and others who have helped.
Thanks for the info. I have a few questions and some information from the FORD Truck shop manual vol 3/4 electrical/body.
FMC400,
I have the dummy light in the dash. I do not think it came with the truck originally, (I think the instrument panel was changed to lower the miles) I am not sure though. (I just figured out a way to tell typing this note, look at info below about the wiriing) So I am definatley not getting volts from the stator on the alternator. Sounds like it is broken inside. NBD, I will have to keep my eye on the alternator to make sure it still puts out a charge and I don't get stuck somewhere. I am going to connect the edlelbrock up to the solinoid connector on the factory wire harness (does anyone have an extra wire harness for that connection, mine was cut off). once I get the wire harness straight I can continue with connecting my carb.
For future information here is what the manual says to do to test the : Rectifier short or grounded and stator grounded test - on bench
(the manual gives you the option to test on the bench or on the vehicle)
Page 31-01-5 under bench tests.
get an ohmmeter, contact one meter probe to the alternator BAT terminal and the other probe to the STA terminal (rear blade terminal). Then reverse the meter probes and repeat the test. A reading of about 60 ohms should be obtained in one direction and no needle movement with probles reversed. A reading in both directons indicates a bad positive diode, a grounded positve diode plate or a grounded BAT terminal. (that is the test for Rectifier Short or grounded) (here is the one for stator ground test).
Perform the same test using the STA and GND terminals of the alternator. A reading in both directions indicates either a bad negative diode, a grounded stator winding, a grounded stator terminal, a grounded positive diode, or a grounded BAT terminal. Infinite readings (no needle movement) in all four probes positions in the preceeding tests indicates an open STA terminal lead connection inside the alternator.
Why did I just type in all that stuff for the tests, when clearly the stator is not working? Maybe someone will get some use from the tests. There are a bunch of other handy tests too, like charging system, charging system fuse link, Indicator light-alternator charging system, Ammeter-alternator charging system test, field circuit and alternator test, regulator I and S circuit with ammeter test, S and I circuit with indicator light test. The manual is worth its weight in gold for me. I just need to get out in the cold and run the tests.
I really have some issues with my wire harness. The person I bought my truck from for what ever reason, cut every lead to everything and twisted them back together without the connectors on the end. So I need to replace many parts of my harness, that is difficult because everyone I have spoken to are not sure what harness goes with my truck. (1976 f-250 4x4 highboy, 360, MT, 410 dana rears, Fith wheel (read trailer towing suspension)). In reading the manual I found reference to a wiring manual, maybe one of you know where I can get one. The name is: Wiring Diagram manual, form 7795P-74. It has schematics and locations of wiring harness. If anyone knows where I can get it please let me know.
I also see that if you have the ammeter or the dummy light, each one has a diffrent wire harness and diffrent tests and sense I want to put the ammeter and the oil pressure into my dash I need to know what wire harness I need.
Bullit390,
The manual drawing for the charge indicator light or gauge says that if you have an ammeter you will not have a connection from the I on your regulator. It states that the I terminal is not used. Now if you have the dummy light for charge indicator in the dash then the I terminal is connected with a green/red stripe wire to the charge indicator light in the dash. If your needle does not move then you might want to do the ammeter-alternator charging system test. I am pretty sure it should show negative with engine off and key on (turn on something electric like radio) and positve with engine running and alternator charging.
FMC400
According to the manual, there is factory wiring between the stator and the S terminal (black with white stripe) if you have the charge indicator light in the dash. Off of that connection is a splice that goes to the choke on the carb. On the charge indicator gauge in the dash, there is no wire between the stator and the S terminal on the regulator, only a wire to the choke on the carb.
Please if anyone knows of someone with the harness manual or the harness for a gauge dash let me know. I could use all wire harness on the ends to connect up my things. Thanks again for all your help, sorry about the extended information.
JIM4

 

Hi jim4, thanks so much for all that information. Those shop manuals literally are worth their weight in gold. It's really a shame when a previous owner cuts up wiring like that; hopefully you can find the parts you need.