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The choke should be receiving only 7V from the ALT STATOR. If you see 14V (BAT VOLT) something is not correctly wired or you have a system fault.
Do you have FORD SERVICE INFO?
Ford did use full voltage fully electric chokes, my 1984 Bronco II uses one. Someone said you can tell if it's full voltage or a 7v assist choke by the type of connector it uses. Flat connector for 7v, round pin connector for 12v. My Bronco does have a round pin connector.
That looks like a 7v choke. The wire is even the right color, it should be white with a black stripe. That should be spliced into the wire that goes to the "s" terminal on the back of the alternator. This electric assist on this choke doesn't even work unless it's over about 60 degrees F in the engine compartment. And when it does work it most likely does get warm, that is how it works.
We just had a good thread on this type of choke on a regular carb a week or so ago. These chokes work on hot air from the exhaust manifold. You should have a fitting in behind that round black piece and then a ppe left this fitting, went down to the exhaust manifold, through the manifold, and then out the bottom and back up to another fitting on the carb. I will look and see if I can find that thread. 99% of the trucks out there, this pipe to the manifold is rusted off.
That looks like a 7v choke. The wire is even the right color, it should be white with a black stripe. That should be spliced into the wire that goes to the "s" terminal on the back of the alternator. This electric assist on this choke doesn't even work unless it's over about 60 degrees F in the engine compartment. And when it does work it most likely does get warm, that is how it works.
The wire is solid dark grey and enters the wiring harness near the distributor. It’s the wire I’m holding in this photo:
I’m assuming it’s the factory wiring harness. Would need to cut it all open to trace the wire and if it’s factory it would be odd that it’s getting battery power all of a sudden. Is it possible it’s supposed to be getting 12V?
It’s almost always over 60* where I live (Palm Desert, CA). My theory is that the choke is either always on or is modulating on/off while running and killing the engine.
Ok, I found it. Not sure if we know your choke housing is original, if you think it is I guess the info I got about the connector pin was wrong. In the diagram I have, the choke is fed with a grey/white strip wire. It is a 12v unit. It is controlled by a 3 terminal oil pressure switch. The switch should have a white/red wire, a red/yellow hash wire, and the grey/white wire going to the choke.
Since I found that the original choke setup was 12v, you won't have any of the hot air setup. You have a full electric choke setup. The oil pressure switch locks the voltage out to the choke until the engine starts and builds oil pressure. If you happen to leave the key in run a little bit or are messing around cranking it a lot and it's not starting on a cold day, the choke would be pulling off and then you never would get it started. That's why they run it through the oil pressure switch.
None of the factory chokes are adjustable, they are all riveted. When the carb is rebuilt, the rivets are ground or drilled out, and you get little self threading screws in the rebuild kit to put it back together. You can do this and make it adjustable.
What are your plans for this truck? Do you have to keep it all original? That variable venturi carb can be problematic. Not many people keep them, they go to a conventional carb and distributor.
Ok, I found it. Not sure if we know your choke housing is original, if you think it is I guess the info I got about the connector pin was wrong. In the diagram I have, the choke is fed with a grey/white strip wire. It is a 12v unit. It is controlled by a 3 terminal oil pressure switch. The switch should have a white/red wire, a red/yellow hash wire, and the grey/white wire going to the choke.
Gotcha. I’ve got one wire coming out of an oil pressure switch right on top (white/red). You can see it in the photo I posted earlier holding the grey wire but here’s another angle:
I see a grey, white/red and red/yellow has running down to the fuel pump area:
White/red is going to the top. The others into a connector. What is that?
Thanks for your help Franklin2. I just want it to run well and reliably at this point. I think it is a mostly unmolested California truck and if I can get it to pass smog even better. This stalling issue isn’t new but has gotten progressively worse to the point where I don’t trust driving it to work (5 miles each way).
From the picture below, it almost looks like you have two oil devices on a threaded fitting. The big round can thing with the one wire in the top is the sending unit for your dash gauge. Then in behind there I think I see another unit, looks like that might be the switch for the choke. Is that the oil filter on the right side of the picture? If so, you might have to pull it off to see better in there. I know from experience it's a bad place right behind the power steering pump.
From the picture below, it almost looks like you have two oil devices on a threaded fitting. The big round can thing with the one wire in the top is the sending unit for your dash gauge. Then in behind there I think I see another unit, looks like that might be the switch for the choke. Is that the oil filter on the right side of the picture? If so, you might have to pull it off to see better in there. I know from experience it's a bad place right behind the power steering pump.
I pulled the sending unit to get a better view (and replaced it anyway). I'm with you, I think the connector is part of the wiring for the choke.
From bottom to top:
Fuel pump (replaced not too long ago)
Oil pressure sending unit
Oil filter
After replacing the sending unit I started the truck up. No stalling and I let it run for 5 minutes. Ran down the street and it seems to be running very good, smooth shifts, power good. Went back to the driveway and turned it off. Let it sit about a minute and it fired up again. Went down the road but stumbled a bit, down on power. Back on choke? Got it back home. As soon as I parked I heard a change in idle and it was back to running well. I fiddled with the connector at the choke and the idle changes a little. It's very loose on there so I might try shimming the post and fitting the connector over that when it cools down.
On a side note, the oil pressure indicated on the dash is much more stable than before!
ETA: I was able to squeeze the connector a little bit so it fits tight over the tab. That didn't really make a difference. It runs pretty good sitting in the driveway. Putting it into a drive gear and the idle drops and it starts to stumble. It's down on power (like by half) when driving.
The carb you are looking for is actually a 7200VV. An earlier (and preferable IMHO) version was termed the 2700VV, non-computer controlled idle mixture. Hard to find because people threw them away. Basically a case of not understanding what they had. VV's aren't new. Every single rice-rocket from the 70's to the late 90's had variable venturi carbs. The jap bikes were always in a performance war during that time (and today), but all of them used the same style VV carbs. Like these bikes or not, you have to admit they put out an amazing amount of power from a tiny package. And their horsepower technology tends to predate that used on production automobiles by a few years. I can remember when every "hot" Kawasaki street bike had dual overhead cams (and VV carbs )while the very few publicly sold cars available with such technology bore names like Cosworth and Ferrari and such.
Not to say Ford's VV was in such a class, but it was a surprisingly good effort.
It's interesting to note that the same VV carb can feed a 2.0 Pinto engine all the way up to a 460 the correct mixture with no adjustment. Of course the 460 will run out of breath around 4000 rpm's due to the venturis not being quite THAT big.
All that said, I've found a 2700VV's on 77-8 Granadas in the junkyards. The owners usually say "you really want THAT!" (more non-believers ) and charge me $5 or so. I rebuilt it and drove it every day in my 351W F150. I ran it with the 70's non-computer Duraspark II setup. One day the hot rod bug bit and I could no longer stand the thought of having a "2 barrel" any more. I just HAD to swap it out for an Edelbrock 4BBL carb and Weiand Stealth intake. Mileage is close to the same I think, but the VV delivered "smoother" power at all speeds.
I pulled the old+leaky Autolite 2100 off my wife's Mustang and put the VV on it. She was very pleased with the smoothness of the "new" carb. She reports a noticeable mileage gain. And interestingly enough she can also now lay a black stripe appreciably longer than before. OK, that was me.
VV's aren't without their idiosyncrasies. I've found that you can run a 7200 without a computer but your idle mixture defaults to pretty darn lean and there is no way to adjust it. The cold start enrichener tends to gum up pretty regularly and stick either open or closed at inconvenient times. No doubt if you could remember spray it off with carb cleaner at every oil change this would be much less of a problem. Replacement parts for the things seem to be getting rarer and rarer.
A "better" 2 BBL is hard to find. The VV's certainly aren't to everyone's taste. Certainly not for those who can't be bothered to understand them. Most people fall into that class, hence the VV's "bad reputation".
Good luck with yours. Should you choose to go with a Holley 2 BBL, that's certainly an option. I've never used one but have heard they work OK".
You say you ran a 7200 vv with a duraspark II ignition system.... I am thinking of trying this exact same thing..... Did you plug the vacuum advance on the distributor or use manifold vac?.... And what about the feedback stepper motor on the side of the 7200vv carb... Did nothing plug into it?
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)while the very few publicly sold cars available with such technology bore names like Cosworth and Ferrari and such.
) and charge me $5 or so. I rebuilt it and drove it every day in my 351W F150. I ran it with the 70's non-computer Duraspark II setup. One day the hot rod bug bit and I could no longer stand the thought of having a "2 barrel" any more. I just HAD to swap it out for an Edelbrock 4BBL carb and Weiand Stealth intake. Mileage is close to the same I think, but the VV delivered "smoother" power at all speeds.
