Alternator and electric choke questions
#1
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Alternator and electric choke questions
I've got a couple of questions for you all if you have a minute (or judging by the length of this post, a half hour).
Basics: 1973 F-100 4x4 360ci
Situation: It idled very roughly cold. I noticed the choke plate didn't close all the way so I backed the adjusting screw out some and with that it idles excellent at first. Once it starts warming up, though, and the choke plate opens up some, the rough idle is back. My first thought was that the choke plate opens up too quickly because when the rough idle starts, you can push the choke plate back down and it idles fine. I replaced the thermostatic spring with a new one. Same problem. I checked the setting on it "1 lean" still the same prob.
Question # 1: The thermostatic spring attaches to the choke housing. The thermostatic spring housing has a wire coming out if it and into the alternator, I beleive. What does this wire do? Does that mean that this is an electric choke?
Question # 2: While working on the truck last night, the new battery went dead after running the truck for a short while. I jumped it and started it again, same thing the next time I tried to start it, then the alt light came on. Does this sound like the alternator has gone bad or could it be the regulator, or is there no way to tell without taking it off and having it tested? (holy runon sentence, batman)
Question # 3: If the alternator is in fact bad, and the wire going to the thermostatic spring does in fact mean that it is an electric choke, then could the alternator also be responsible for my idleing woes? Could the alt be not supplying electricity to the spring and therefore the choke plate is opening too quickly?
Thanks tremendously for any and all help.
Travis
Basics: 1973 F-100 4x4 360ci
Situation: It idled very roughly cold. I noticed the choke plate didn't close all the way so I backed the adjusting screw out some and with that it idles excellent at first. Once it starts warming up, though, and the choke plate opens up some, the rough idle is back. My first thought was that the choke plate opens up too quickly because when the rough idle starts, you can push the choke plate back down and it idles fine. I replaced the thermostatic spring with a new one. Same problem. I checked the setting on it "1 lean" still the same prob.
Question # 1: The thermostatic spring attaches to the choke housing. The thermostatic spring housing has a wire coming out if it and into the alternator, I beleive. What does this wire do? Does that mean that this is an electric choke?
Question # 2: While working on the truck last night, the new battery went dead after running the truck for a short while. I jumped it and started it again, same thing the next time I tried to start it, then the alt light came on. Does this sound like the alternator has gone bad or could it be the regulator, or is there no way to tell without taking it off and having it tested? (holy runon sentence, batman)
Question # 3: If the alternator is in fact bad, and the wire going to the thermostatic spring does in fact mean that it is an electric choke, then could the alternator also be responsible for my idleing woes? Could the alt be not supplying electricity to the spring and therefore the choke plate is opening too quickly?
Thanks tremendously for any and all help.
Travis
#2
Alternator and electric choke questions
You do have an electric choke. The choke has a heating element inside it, that assists the spring in warming up faster. If you disconnect the wire from the alternator, it should slow the choke down. Could there be something wrong with the alternator, making it give too much voltage to the choke? Probably not, but I am not sure.
The factory wants the choke to pull off as quickly as possible, to reduce emissions. The engine has a delicate balance of parts on it to achieve this. Some parts that could be malfunctioning or missing are:
Original aircleaner with a functioning flapper valve in the snorkel, and a intact hot air pipe coming from the exhaust manifold to the snorkel. This will make it warm up quicker and idle smoother.
Original thermostat. Make sure your thermostat is working, and that somebody didn't put a 160 degree one in. I would put at least a 180 degree in it.
The factory wants the choke to pull off as quickly as possible, to reduce emissions. The engine has a delicate balance of parts on it to achieve this. Some parts that could be malfunctioning or missing are:
Original aircleaner with a functioning flapper valve in the snorkel, and a intact hot air pipe coming from the exhaust manifold to the snorkel. This will make it warm up quicker and idle smoother.
Original thermostat. Make sure your thermostat is working, and that somebody didn't put a 160 degree one in. I would put at least a 180 degree in it.
#3
Alternator and electric choke questions
Take the truck down to a parts store and get the electrical system tested. Low voltage can cause idling problems also. Otherwise check the condition of your ignition system.
The electric choke element is used to make the choke pull off quicker. If it is disconnected the choke will stay on to long. The choke wire should be connected to the alternator stator terminal.
The electric choke element is used to make the choke pull off quicker. If it is disconnected the choke will stay on to long. The choke wire should be connected to the alternator stator terminal.
#4
Alternator and electric choke questions
OK, let's see if I can confuse the issue even more.
Sounds like you have 2 problems going on at the same time.
1) Charging system. A new battery that goes dead would indicate a charging system malfunction. Without going into a lot of detail, (OK,on second thought it is a lot of detail) the regulator supplies 12 volts (or nominal battery voltage) to the field terminal on the alternator to tell the alternator to charge. This is switched on by the regulator when the regulator gets 12v from the ignition switch and the voltage is below the cutout voltage (usually from 13.8 to 14.4 volts). When the voltage reaches the set point in the regulator the field current is then switched off until the voltage drops enough to kick it back in. Any interruption in the field current will prevent the alternator from charging. If you bypass the regulator and apply 12 volts to the field terminal on the alternator, it will put out the max it possibly can (up to about 18 volts). Don't do this for very long and definitely don't do this with a dead battery. The alternator will pass enough current to possibly blow out the diodes in the alternator. A fully charged battery will keep the current down to an acceptable level. If the voltage rises rapidly when you do this, you can assume the problem is not in the alternator. Check the regulator and wiring instead.
When the alternator is charging, the stator terminal on the alternator will put out about 6 to 8 volts, about half of the total alternator output. Consider it to be like a center tap on a transformer. This lowered voltage is a supply for......wait for it...
2) The electric choke heater. This either helps to open the choke or on some systems is the only thing that opens the choke.
The bi-metal spring in the choke housing can, over time, get weak and not close the choke as tightly as it once did. You can compensate for this by turning the choke housing toward a richer setting although it may also open a little slower than was originally intended. A good rule of thumb that I use is that when the engine is cold, (sat overnight if the temp is warm, 60° to 70° is good) with the engine off and the throttle held slightly open the choke flap should just be closed. Or put another way, rotate the choke housing until the choke plate just closes. Also, while you're doing this, rotate the choke housing both ways to make sure the tang on the choke spring has engaged the slot on the arm inside the choke housing. It's easy to miss and the choke won't operate properly if not in the slot.
If you're still awake after reading all this, I hope it helps and good luck.
Greg
Sounds like you have 2 problems going on at the same time.
1) Charging system. A new battery that goes dead would indicate a charging system malfunction. Without going into a lot of detail, (OK,on second thought it is a lot of detail) the regulator supplies 12 volts (or nominal battery voltage) to the field terminal on the alternator to tell the alternator to charge. This is switched on by the regulator when the regulator gets 12v from the ignition switch and the voltage is below the cutout voltage (usually from 13.8 to 14.4 volts). When the voltage reaches the set point in the regulator the field current is then switched off until the voltage drops enough to kick it back in. Any interruption in the field current will prevent the alternator from charging. If you bypass the regulator and apply 12 volts to the field terminal on the alternator, it will put out the max it possibly can (up to about 18 volts). Don't do this for very long and definitely don't do this with a dead battery. The alternator will pass enough current to possibly blow out the diodes in the alternator. A fully charged battery will keep the current down to an acceptable level. If the voltage rises rapidly when you do this, you can assume the problem is not in the alternator. Check the regulator and wiring instead.
When the alternator is charging, the stator terminal on the alternator will put out about 6 to 8 volts, about half of the total alternator output. Consider it to be like a center tap on a transformer. This lowered voltage is a supply for......wait for it...
2) The electric choke heater. This either helps to open the choke or on some systems is the only thing that opens the choke.
The bi-metal spring in the choke housing can, over time, get weak and not close the choke as tightly as it once did. You can compensate for this by turning the choke housing toward a richer setting although it may also open a little slower than was originally intended. A good rule of thumb that I use is that when the engine is cold, (sat overnight if the temp is warm, 60° to 70° is good) with the engine off and the throttle held slightly open the choke flap should just be closed. Or put another way, rotate the choke housing until the choke plate just closes. Also, while you're doing this, rotate the choke housing both ways to make sure the tang on the choke spring has engaged the slot on the arm inside the choke housing. It's easy to miss and the choke won't operate properly if not in the slot.
If you're still awake after reading all this, I hope it helps and good luck.
Greg
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