Hi. I just replaced my Holley Truck Avenger with an Autolite 4100 with the 1.08 venturi. At the same time, I put on an electric choke. I noticed that the port, near the choke, where the heat tube (not sure what it's called) is attached (not used now) has a vacuum (suction) on it. I can feel it with my finger. Am I supposed to plug up this port? I think the answer should be yes, but I'm just not familiar with this port. I assume the vacuum comes off the manifold, in which case it needs to be plugged. Just want to check with those more knowledgeable. Thanks.
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conversion to electric choke
- Thread starter valveamp
- Start date
No; the air is needed to both function the choke pull off and keep the heating element from melting the cap. Just run a vacuum hose from the hot air port to the brass tube just behind the choke housing to supply filtered air just as it did with the hot air tubes. What electrically heated choke cap are you using? The Holley was set up with the same filtered air supply hose out of the box.
hmmm. I was not aware of that. I thought it was all electric and it didn't need air. I don't know who makes the electric choke. It was put on by the guys who rebuilt the carb. There is only one brass tube on the carb and I was told that is for the vacuum advance, which is what I have it hooked to. if that tube is for the choke, where do I hook the distributor vac advance? Never had an Autolite before.
Update: I did some Google research and confirmed what you said that the brass tube is just a clean air tube for the original choke system. The vacuum advance port is on the passenger side down at the base. I went to NAPA and picked up a fitting with a hose barb on it and I just installed it. Everything seems to be ok. However, I really don't see any difference in how it runs with or without the vacuum advance hooked up. Maybe that's another problem.....haha.
Biohazard
Full Member
I have always been told to plug the hole. Mikes carb actually sends an expansion plug to block it off, with thier electric choke setup.
If you look into the choke housing, you see a piston that pulls the choke off partially once the engine starts and there is manifold vacuum. By plugging the hole it becomes dead end, and the choke won't pull off. Ford deleted the piston on 2150s that have a diaphragm to pull off the choke. The automatic chokes on Holleys, 2100s, 4100s, and AFBs (Edelbrocks) all have an air intake originally designed to supply hot air from the manifold. And they all need filtered air to the hot air tubes and or choke. Your Holley Truck Avenger was identicle. The reason I asked what cap you have is that Ford made 2 types of electrically heated caps. The '70s type does nothing till the temp reaches 60 degrees, and the '80s type that starts heating at any temp. The Holley cap works on 4100s too. Any of these work better if used in conjunction with the hot air from the exhaust manifold. I've searched Mike's Carbs and can't find any plug as part of an electrically heated choke cap conversion.
I know you guys don't like reading instructions - LOL - but on page 7 of the Holley Truck Avenger Instruction Manual it says - " Choke Fresh Air Intake - Do NOT plug or Block"- so does my Holley street avenger manual - so at least for the Avenger Holleys in regards to the choke air intake- don't plug it off.
SHX
SHX
Biohazard
Full Member
Well bio, the plug in that kit is an expansion or more correctly a welch plug. It would be used to replace the original at the end of the cylinder containing the piston I described in post #6. The cylinder is hard to clean with no direct access. Prying the welch plug out allows access, but these aren't re-usable. The cylinder needs to be clean to allow the piston to move freely and keep the choke from sticking. It has nothing to do with the air inlet port that valveamp is talking about.
chrisd0729
Sr. Member
I also went electric choke but, not sure where to tap a hot wire from. Are you running any 12v circuit that's hot as long as ignition is in on/run position?
Any suggestions on where to run it from?
Any suggestions on where to run it from?
There's no reason to run wire all over. A simple 2 foot wire to the stator terminal on the back of the alternator solves your problem. I know there are people who never tried it but read somewhere that a full 12v source is needed. That's not true . I've used the stator or S terminal on Holley, AFB (Edelbrock), and Ford electrically heated caps for 40 yrs with no problem or delayed choke opening.
blubuckaroo
Grease Monkey
Impossible.
Sure it will open the choke, but it will be delayed.
The choke's resistor running at the stator's 7.5 volts will produce a lot less wattage than the 13 volts it's made to run at.
An exact wattage comparison can be made if by measuring the resistance of the resistor, and making a calculations using ohms law formula W=V2/R.
I'll bet in some climates, the delay might be beneficial, but that's doubtful in AZ.
Thats ^^^^^^the wire i used
The choke opening is NOT delayed by using the stator terminal in even the slightest degree. The OE Bronco choke caps were wired that way. I tried using an oil pressure switch on a 12v source after finding my '87 Crowm Vic was set up that way and there was no difference. I expected a post like yours.That's why I told valveamp in post #12 that those who have never tried it, would have a theoretical issue with using the S terminal. Apparently you're one of them. The wire to the idle solenoid is hot whenever the ignition is turned on, so the choke opens without the engine ever running. So that's not a good idea.
It may not be the best option but its not bad. Mine has been wired that way for 16 years an i have had zero issues.
Some people argue that leaving the key on accidentally would burn the choke coil. No matter where it is wired, alternator or the idle solenoid, it gets power the entire time the truck is running so leaving the key on will not burn it out. Even if i left the key on for hours it would be no different than driving it for that amount of time.
Others argue that it gets too much voltage and would open too fast. I am not convinced that is an issue. Most of the replacement chokes are designed for 12 volts. Even it opens too fast, setting the choke cap to a higher setting delays opening and would compensate.
The other argument is that it starts to open as soon as the key is turned and may open before you get started in the winter. My Bronco starts as soon as i bump the key, summer and winter but it takes the choke at least 30 seconds to a minute to open from just electricity. If I ever have to crank for that long before firing up, then i have bigger problems to worry about.
Some people argue that leaving the key on accidentally would burn the choke coil. No matter where it is wired, alternator or the idle solenoid, it gets power the entire time the truck is running so leaving the key on will not burn it out. Even if i left the key on for hours it would be no different than driving it for that amount of time.
Others argue that it gets too much voltage and would open too fast. I am not convinced that is an issue. Most of the replacement chokes are designed for 12 volts. Even it opens too fast, setting the choke cap to a higher setting delays opening and would compensate.
The other argument is that it starts to open as soon as the key is turned and may open before you get started in the winter. My Bronco starts as soon as i bump the key, summer and winter but it takes the choke at least 30 seconds to a minute to open from just electricity. If I ever have to crank for that long before firing up, then i have bigger problems to worry about.
Steve83
Bronco Guru
It matters WHICH choke heater you have installed on your particular carb. If it's designed for 12V, then you need to run 12V (key-switched in RUN only) to it for it to work right. If it's designed for 6V, then it should be connected to the alternator S terminal. If your carb was EVER replaced or even rebuilt, then you have to inspect it to find out what's on it before you hook it up. Running 12V to a 6V heater will burn it out instantly.
The vacuum to the choke side of the heater tube comes from inside the carb - there's no easy way to block it. If the mating steel tube inside the exhaust manifold is perforated, wrap soft copper tubing around the outside to bypass it, and restore those vacuum lines. In any case: if the carb HAS this system, there's no reason NOT to use it.
If the carb has no exhaust choke heater, and the tube in the manifold is perforated, plug both ends of it.
The vacuum to the choke side of the heater tube comes from inside the carb - there's no easy way to block it. If the mating steel tube inside the exhaust manifold is perforated, wrap soft copper tubing around the outside to bypass it, and restore those vacuum lines. In any case: if the carb HAS this system, there's no reason NOT to use it.
If the carb has no exhaust choke heater, and the tube in the manifold is perforated, plug both ends of it.
I have yet to hear from anyone (besides myself) who has actually used the stater terminal on any and all electrically heated choke caps. My experience is that it always works. The Ford caps in '77 models were electric assist, in that they only started to heat when the under hood temp reached 64 degrees, according to the shop manual. My '85 shop manual describes 2 types. One the assist type and another that works at any temp. I check continuity on caps chilled to 35 degrees, to see which type they are. Holley and AFB caps both call for a 12v source, but work as well with the stater terminal. I know it works. I don't find someone, who hasn't tried it, saying it shouldn't work persuasive.
blubuckaroo
Grease Monkey
I say put both a Ford carb, and your aftermarket carb on the bench, connect them both to the same voltage source at the same time, and have a choke race.
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