12v Electric Choke Wire Help

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12v Electric Choke Wire Help

FormerBigDaddy
This post was updated on .
Hello all,

I'm currently ready to upgrade to a 3g alternator on my truck (84 f350 460 auto).  I have everything I need ready to go on that but I need help figuring out how to wire up my 12v choke from my edelbrock 1406.  I didn't realize until now, that the PO owner had the electric choke wired to the 1G alternator as if it were a stock carb.  I have since learned that the stator is only 7v and not enough for my carb.  I understand it CAN be done but i'd rather do it right while I'm messing with the wiring. I know i SOUND like i know what I'm doing here but i really don't.  I only know from what i've read and seen in pictures and videos and I couldn't tell you where to locate a proper 12v source or even what a 12v source is. I don't know the first thing about relays, switches, etc.

Thanks in advance!
1984 F350 460 Auto
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
Chris - Thanks for joining.  We can help you through this, and it is probably something that needs to be on our 3G page, so we will want to do it "well".

However, as said in the FB chat, I'm headed out right now and won't get to this until either late today or tomorrow.  Perhaps the others will help in the interim.

Having said that, please go to the New Members Start Here folder, read the guidelines, and then start a new thread about yourself and your truck.  The guidelines are important as we hold everyone to them.  And, don't forget the signature thing as that helps us answer questions w/o having to scroll back through everything trying to figure out what you have.  Instructions for a signature on on the FAQ's page: Bullnose Forum/FAQ's in the menu.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

85lebaront2
Administrator
In reply to this post by FormerBigDaddy
I will reply to that one. The 351W used a 12V electric choke operated via a relay from the alternator, but there is an easier solution, first does your truck have the electric in-tank pumps? If it does you are halfway there, if not, go to a parts store and buy an oil pressure switch for a 1987 Horizon 2.2L, it will have 3 terminals on it. The 2 outer ones (parallel to each other) are normally open, and close with oil pressure. This will provide you with an engine running closed switch. Use a 12V source, if you come off the alternator or battery use an in-line fuse, probably 20 amp, so if something shorts you won't have a fire. Chrysler used these for oil pressure light and choke power.
Bill Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 1994 Taurus LX Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

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Re: 12v Electric Choke Wire Help

FormerBigDaddy
This post was updated on .
I do have an in tank electric fuel pump. But the PO made modifications to the fuel systems and I’m pretty certain it wasn’t originally that way.

Unfortunately I don’t understand much else of what you said. I much appreciate the reply but gonna have to get more basic with me. I don’t know what 12v sources even are or where to find them.
1984 F350 460 Auto
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
Ok, let me see if I can help.  What Bill suggested is brilliant, and that's exactly why we have a forum - someone has an idea and someone else has a better one.

The drawing below shows your fuel pump control circuit.  In the upper left you'll see "Hot In Start or Run", and below that a red wire with a yellow hash mark (R/Y H) that goes from Fuse 18 to the Oil Pressure Switch.  That means that when the key is either in Start or Run there is power provided to the oil pressure switch via the fuse and that wire.

As shown the switch is "open", meaning there's no connection between the terminal on the top and the one on the bottom.  But there's a note that says "Closed with engine running", and that means that battery voltage will flow across the switch to the Fuel Pump Cutoff Relay when the engine is running.  And that will close the contacts on that relay and power the fuel pump.

But, I've drawn a red arrow and added "Choke".  If you tap into the red/yellow hash wire after the oil pressure switch you can run that wire directly to the choke and it will get battery voltage when the engine is running, and only when the engine is running.

So, where are these components?  The oil pressure switch is on the back of the engine, right in front of the firewall and behind the carb.  If you need I can get pics of the one from Big Blue, but you should be able to find it easily, and it'll have two wires to it, and both are R/Y H.

So, which one do you tap into?  The one that goes to the fuel pump cutoff relay, and it is between the master cylinder and the driver's fender on the firewall.  I've put an illustration below that shows what it looks like.

So, are you ok with doing that wiring?  Do you need suggestions on how to do that?  (Please don't tell me you are going to use an insulation displacement connector to tap into the R/Y H wire and are going to use a cheap wire crimper to crimp the terminals.  )






Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

myrl883
Ford used a 3 terminal oil pressure sender just like Chrysler... It was commonly used to turn the electric fuel pumps on 460 trucks off if oil pressure was lost. I think the easiest would to be to use one as suggested above, or wire in a relay to control power to the choke. If you use a Bosch style relay, 7 volts is enough to hold the coil in. Use the stator wire on the control side of the relay, then use the load side of the relay to power your choke.

However you wire it, make sure you only have power in RUN, and not ACC!
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Re: 12v Electric Choke Wire Help

Rembrant
In reply to this post by FormerBigDaddy
I know there's already lots of great info posted here, but I was just going to add that you could buy one of the smart relays like the Rostra one here listed below:

https://www.ebay.com/itm/Rostra-250-2951-SourcePWR-Plus-12V-7-5-Amp-Intelligent-Accessory-Power-Supply/123077949915?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

I am currently running my Holley choke with the Ford factory wire from my 1G alternator, and it seems to work OK. The only reason I did this was after some reading online I found a lot of people that had done the very same thing with Holley carbs on Fords going back decades. However, I do remember reading that the Edelbrock carb chokes don't like the lower 7vdc supply?

In any case, yes, I know it is not correct this way, but if I ever do get around to changing it, I was just going to use one of these relays so it could be a stand alone circuit.
1984 F150 4X2 Flareside. Mild 302 w/GT40 heads, BBK headers, Holley 4bbl, XE256H Comp Cam, M5R2 5spd swap, Magnaflow full duals. Fresh Medium Blue Metallic in August 2019.
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
That's interesting, Cory.  Apparently it senses the voltage increase when the alternator kicks in and then closes its internal relay.

However, in the video on their site I dislike the way they run long wires from the battery through the firewall without a fuse.  I think that is poor practice.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

Rembrant
Gary Lewis wrote
That's interesting, Cory.  Apparently it senses the voltage increase when the alternator kicks in and then closes its internal relay.
Yes, that is my understanding of it. I have it on my to-do list for down the road. The carburetor choke was my first thought for it, but I could also use it as a trigger for other devices so that I don't have to go digging through my wiring harness to get an ignition on/run signal.
1984 F150 4X2 Flareside. Mild 302 w/GT40 heads, BBK headers, Holley 4bbl, XE256H Comp Cam, M5R2 5spd swap, Magnaflow full duals. Fresh Medium Blue Metallic in August 2019.
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
That should work, but with the minor problem of those accessories not coming on when the alternator fails.  But then that would also be the case if you used the stator wire to pull in a relay, which I've done frequently.

I guess I was just put off by several things about that unit.  First, they don't tell you how it works.  Then they say it "illuminates the fuse".  What?  Maybe that is because they speak both English and Chinese, and their English is far superior to my Chinese.  And last, they show using no fuse and, to top it off, use a cheap crimper for the connections.

So maybe I shouldn't penalize the product with the way they present it?  The product itself seems like it would solve a lot of problems.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

FormerBigDaddy
In reply to this post by Gary Lewis
Ok I can follow this... a picture would be nice.

That being said, I'm not sure what i have is a stock setup.  I know i have a electric fuel pump, but the truck didn't originally so I'm not so sure about having a fuel pump cutoff relay in a stock location.
1984 F350 460 Auto
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
Ok, good point.  If it didn't originally have an electric pump you may not have all of the other bits, like the oil pressure switch and the cutoff relay.  I have a meeting at church in a bit, but can take pics when I get home of the switch and the relay.

But, are you ok to do the wiring?  Do you have wire, connectors, and either a ratcheting crimper or a soldering gun?
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

FormerBigDaddy
If I have that wire and can locate it I can definitely do the wiring.
1984 F350 460 Auto
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
Ok, glad you can do the wiring.  Personally, I solder all connections and use adhesive-lined heat shrink tubing to protect the connections.

Anyway, I looked for my pics on doing the work on Big Blue in the area we are talking about, and it turns out that it was done before I started this forum, so was while I was on FTE.  Unfortunately FTE doesn't allow copying the link to a picture there and placing it here, so all I can offer you is this URL.  If you go there you'll see an illustration of where the oil pressure switch is, and if you scroll down you'll see my pics showing the switch I used.

And when I get home I can take a pic of where the fuel pump relay is on Big Blue.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

85lebaront2
Administrator
In reply to this post by myrl883
I have never seen a 3 terminal used on a Ford, the oil pressure switch on the 460s with the hot fuel hanling package are two small pins in a weatherproof connector. Here is where it sits:

Since the 1984 models used the 12V ignition switched power through that switch makes it easy to get 12V for the choke, FWIW, the 7 volts from the alternator is enough to close a Bosch relay I used it to give me a charging circuit for my 5th wheel trailer batteries.
Bill Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F-350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 1994 Taurus LX Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

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Re: 12v Electric Choke Wire Help

myrl883
My '81 F100's 302 used that same oil pressure sender. I can't for the life of me remember why, but it had to do with California emissions. It was a EEC-III truck.
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
In reply to this post by FormerBigDaddy
Here's a pic of the relays on Big Blue.  I've circled three since I've seen the fuel pump relay in both the 9C392 housing as well as by itself on the firewall.  But look for the red/yellow wire going in as well as yellow, black, and pink/black hash wires.



Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

FormerBigDaddy
Ok i'll take a look in there today.  I assume this red/yellow wire goes to the largest black box in the pic?
1984 F350 460 Auto
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Re: 12v Electric Choke Wire Help

Gary Lewis
Administrator
The black box is just a housing that holds the relays.  The red/yellow wire goes into a plug, like the black plug on the right that connects to the green thing, which is the relay.

In that black housing there are two relays.  The fuel pressure relay is supposed to be in there, but is sometimes on the firewall like the one on the right in the circle.
Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI

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Re: 12v Electric Choke Wire Help

FormerBigDaddy
Couldn’t locate an oil pressure sensor on the back of the engine. Honestly not sure if I found the relay either. I have a ton of relays on the driver side fender. I did find a red/yellow wire but it was going to this unused plug.
1984 F350 460 Auto
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