how to wire the electric choke

[pw520a 19]

I have the stock fuse block on my 69 I'm not sure how to hook the electric choke  there, I've been given conflicting information on the alternator some say not enough voltage? for sure not the coil, maybe the windshield wiper hot wire? any suggestions would be appreciated.

[RPM 1,190]

Any switched 12v source should do. 

[BlueCoupe 8]

I used the alternator stator terminal to trigger a relay, which I wired to the battery side of the starter solenoid. I used a fusable link between the relay and starter solenoid. There is also a lot of good information here:

 

[pw520a 19]

thanks for the information, a great help!

[Midlife 814]

The STATOR terminal on the alternator is what Ford used when it installed an electric choke.  The STATOR is RUN-only, and somewhat less than 12 Volts, which allows the choke to stay on a wee bit longer.

[stangs-R-me 120]

I had been running a Holley 600 CFM Double Pumper with a Holley 37-485 Electric Choke kit since  2012 and had it hooked up to the Stator terminal as Ford always did in the 70's & 80's..   Choke always opened fully in what seemed to be a normal amount of time.

Replaced the Holley earlier this year with a Summit M08600VS 600 CFM Vac Secondary with Electric Choke and again hooked it up to the Stator terminal.   It also opens fully with no issues.

Both the Holley Choke Kit and the Summit Carb state you MUST use a 12V source and I was going to wire in 12V if the Summit carb really needed it.   The Summit carb is actually made by Holley and the choke caps looked identical and the flat coil spring inside of both caps was the same thickness too.    

I like the relay idea shared by BlueCoupe, that would eliminate the need to run a wire inside the car to get 12V switched power as there is no source under the hood of a stock '69 Mustang.

Doug

[Caseyrhe 650]

You could also use the female plug at the fire wall harness, currently using it on my 69 and 2- 70's

[Mach1 Driver 560]

1 hour ago, stangs-R-me said:

 I like the relay idea shared by BlueCoupe, that would eliminate the need to run a wire inside the car to get 12V switched power as there is no source under the hood of a stock '69 Mustang.

Doug

Well, wire 904 Green/red stripe that goes to the regulator plug "stator" pin is live when the ignition is in "start" or "on". Since its only about an 18ga wire, I would connect that to a relay coil and use the N.O. contacts to drive the choke, wired directly from the battery.

[Her69fastback 3]

Don’t mean to high jack your post. I have a 1 wire alternator. Where can I get 12v for the choke? Thanks for the help 

[Mach1 Driver 560]

Well, I mentioned wire 904 in my previous post. It should still be in the harness, even if the regulator has been removed. That is really the only source for switched power in the engine compartment. See the bottom of the page:

[stangs-R-me 120]

2 hours ago, Mach1 Driver said:

Well, wire 904 Green/red stripe that goes to the regulator plug "stator" pin is live when the ignition is in "start" or "on". Since its only about an 18ga wire, I would connect that to a relay coil and use the N.O. contacts to drive the choke, wired directly from the battery.

All these years, I guess I've just missed when wire 904 was mentioned as a switched 12 volt source under the hood !!

Thanks,

Doug 

[Midlife 814]

904 is RUN-only and available in the engine compartment when you have an ammeter.  The alternator indicator lamp version o f 904 is routed differently to the voltage regulator and is not suitable for RUN-only relay capability.

[Mach1 Driver 560]

8 hours ago, Midlife said:

904 is RUN-only and available in the engine compartment when you have an ammeter.  The alternator indicator lamp version o f 904 is routed differently to the voltage regulator and is not suitable for RUN-only relay capability.

Well that's interesting Mid- I have the ammeter version and am not familiar- what makes the indicator light version unsuitable to run a relay coil?

[Midlife 814]

There's a 15 ohm resistor in that circuit, so running it may cause the voltage to drop enough to not work the relay.

[Mach1 Driver 560]

 

21 hours ago, Midlife said:

There's a 15 ohm resistor in that circuit, so running it may cause the voltage to drop enough to not work the relay.

Well those sneaky SOBs !! I just looked at the tach version wire diagram and sure enough there is a resistor, but it doesn't give a resistance value. I assume they used a resistance wire? You may be the only guy on the planet that knows that.

However, I checked out a typical 30A 12v Bosch automotive relay. They have a 75 ohm coil and 160ma current draw, with an 8v pull-in and 1.2-5v drop-out. If you put that relay in series with a 15 ohm resistor it still has 10v available for pull-in, and as I mentioned it only needs 8v. So the relay would still work, even on a tach car.

Thanks for the info Mid, I'm always learning from you.

[jrw69 16]

I ran 12 V for choke to green/red stripe on the voltage regulator, works fine with a 670 Street Avenger on my 69 Mach 1

[Her69fastback 3]

Thanks for all the help 

[pw520a 19]

thanks much for all your posts, great information! I am going with midlife's recommendation of stator terminal.  

[Rcodenewf 44]

I've also used the stator terminal for years with success. Simple and effective.

John