I got a new Edelbrock 4 barrel for my car and will be running a new wire to the choke mechanism. What size fuse is ample to protect that wire. I have some 3 amp fuses? Is that enough, too much?

Thanks,
Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

If the current draw for the choke isn't listed in the carb specs, then use an ohmmeter to measure the resistance of the choke wire to ground (the body of the carb).

13.8 volts / Resistance in ohms = Current flow in amps.

Try a fuse rated at 1.5x your projected current flow.

- Mac

Might also be a good idea to check the resistance when the choke is cold, and again when the choke is hot. Make sure to disconnect power so you don't fry the meter. Use whichever resistance is LOWER for your calculation.

- Mac

Why not just use a multimeter set on amps and measure the current, directly?

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Oh sure, take all the fun out of it!

Thanks!

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Hooked up the electric choke and ran current through my multi-meter, and only measure .04 amps? Is it possible that it only draws that much? If so, what size fuse should I run?

Electric choke does work by the way.

Thanks, Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Hard to see that 0.04 A is right, when it's engaged.

Fuse? Never even thought about that for that app. You been hanging with Sam Powell? I think mine have run to the old coil + wire, which would piggyback fusing on the fusible link, IIRC.

Lou

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Home of Slant6-powered fun machines since 1988

Maybe!! Sam's a good guy anyhow. I will assure that my set-up is 99% less complicated than Sam's car.

I'll just piggyback off something else that is fused.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Electric choke needs to be powered from switched 12 volt source not directly connected to ballast resistor, coil, or voltage regulator; otherwise coil will not receive sufficient voltage to power spark plugs, and over charging problems from voltage drop. This method was used in the larger Chrysler cars back in the day.

This is accomplished by triggering a relay from the high side of ballast resistor, and using a fused 12 volt source such as threaded lug on starter relay to power choke.

I went through this same drill (An agonizingly long discussion on over charging that touches on electric choke’s contribution near bottom of page three) last summer after incorrectly powering a Holley choke for several years, and having voltage drop problems / overcharging problems. Top of page five there is a warning on electric choke power source here. An electric choke is mostly the same for all brands. I called Holley regarding fuse sizing; 10 amp was recommended.

Idle was much better after installing relay to operate electric choke, and a lot of the overcharge problem was eliminated.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I have a relay powering a terminal strip out under my hood where I am picking up switched 12V. I have plenty of room so I can power it individually or piggy back it to something else. That is why I asked about the fuse for it. I must have done something wrong to get a reading of .04 Amps.

Thanks

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Perhaps you had the wrong scale. Try a new reading on lowest scale. Probably will read around 1 to 4 ohms.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Interesting info, Bill, thanks. I'll have to look into that for upcoming elec choke apps. Of course, most of my cars have had MSD's or similar ignitions, which do not relay on coil + for main power, so maybe that's how I got away with it.

Lou

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Home of Slant6-powered fun machines since 1988

This sounds complicated. Why couldn't you just run a wire from the starter relay to power the choke?

Danny

The goal is to have the choke only activated when engine is running, and not reduce voltage to coil via a parallel path to ground. The choke has to be powered any time the engine is running to keep it open after warm up.

Starter relay’s threaded lug is hot all the time, its other terminal connections only hot when transmission is in park or neutral, clutch is depressed on some years, or key is in start position.

Choke heater cannot be allowed to be powered when engine is not running as two conditions will result: one, battery will be drained; and two, choke heater requires cooling from engine vacuum when powered or it will over heat and burn out.

Powering choke from oil pressure warning light can be accomplished, but requires digging into dash finding a good location to tap circuit ahead of indicator light in such a way not to illuminate oil pressure bulb at a reduced intensity via a parallel path to ground when engine is running. And, the added fun of running that new circuit through fire wall… way too much PIA for this old guy. LOL

Some auto manufactures trigger choke relay from field wire between alternator and voltage regulator. I think Chrysler occasionally used this method on a few of its larger models over the years. You can scan various wire diagrams of these other models here for different methods used; Here.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC