Thread: 350 SB chevy build...wiring help

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Good morning folks,

I've used this site in the past and the information I get has been great and very helpful. So, to refresh... I built (with mechanics help) a 350 small block chevy (69-78) from a Camaro. I had a Jeep TJ 2.5 engine was dead, so I swapped it out. My issue is the wiring... I have it all set up, but its a mess and I'm having an issue with the electric choke.

Just looking for a simple diagram on how to wire everything (with using relays) I don't really understand it.

- Distributor
- Carburetor (holley with electric choke)
- starter
- alternator
- Push start

Everything is all connected to the battery right now just while I figure this out. I'd like to have it cleaner and not have to hook them all to the battery. Most cables are #12 except for the battery to the starter and the grounds.

If anyone is willing to help me out, feel free to post a reply and I'll answer questions if you need more info/photos.

Also... when the ignition is shut OFF (no power) the Electric choke runs EXT HOT! To the point the wire actually melted... and this kills my battery EVERY night. I try running acc to see if there is power.. but the ignition is off. When the electric choke red cable to connected and connected to a power source it doesn't shut off (when that source if killed).

I'm new to this.. and I enjoy doing this. I completely rebuilt the whole vehicle from the frame to the engine... and its a hobby so take it easy.

Thanks for your time,

_____________________________________________________________________
ROOKIE17

"Respect Each New Sunrize" Ted N.

Hard to say exactly what is going on without actually seeing what you're doing.

The choke heater is seeing power with the key off regardless of how you think it's wired. Depending on the wiring, it could be backfeeding from somewhere else.

You really need at least a test light (a multimeter would be better) to check wiring. With the key off, the test light should not light up when touched to the choke heater feed. If it does, you have power coming from some place. The multimeter is better because it will show a low level power feed that might not light a test light.

I would hazard a guess that the relay circuit you have is using a relay to power the choke so that the trigger can be hooked up to any key on power source without over loading the circuit.

Thanks for the reply... I'm working on a sketch right now. I don't have the relay installed yet... but I was told to mount one by the battery (the only available space) and run my Carb, Push start, alter to it. I just made a diagram of what I'm looking at on PAINT lol with the RELAY.

I don't know how to upload photos or video. I'm at work for another hour... when I get home I'll make a video to show what I'm "rigging up" based on a diagram I got from here a few months ago... but it was all connected to the battery and I don't want that.

Thanks again

As Mike said the choke should not have power with the key off. If the wire melted either the wire is too small or the choke-stat is defective.

IMG_0919.jpg

Hopefully these photos work... only took 2 hrs to get them to load

The second photo is a diagram I made up this morning... and what I want to do. I just want to make sure it will work/if its right.

I don't understand your alternator wiring. The large power wire from your alternator needs to go the the battery somehow.

Perhaps this can help? It's for a GM point ignition but other than that it'll get you closer to the wiring connections.

OK. First, delete the water hoses from your electrical diagram, it's confusing.

Second: get a wiring diagram for the vehicle. Think of it as a road map and you'll be able to read it fine with a bit of effort. An hour searching the net on how to read a chematic will do wonders for you.

Every vehicle has a distribution junction where the positive cable branches out to feed the various circuits. Ultimately, that is where the alternator output and sense wires must go. The way it is wired now, the alternator can only sense the voltage at the battery. It will cause reduced voltage to everything.

Think of the relay as a coil and a switch. Two contacts feed the coil, and the others the switch. One side of the coil goes to ground. The other gets positive from a control. In your case, I'm guessing a toggle switch. When the coil is energized it closes the switch.

Depending on the relay, it could have more than one switch, and the switch could have normally open and normally closed contacts. If it has both N.O. and N.C. then it will have three contacts per switch. One will be common, one N.C. and the third will be N.O. for what you are doing the source voltage should go to the common, and the load goes to the N.O.

Your wire is burning up : 12 AWG is more than heavy enough for a choke (16 AWG should be ok) so you have an additional issue there somewhere. Crappy terminals or poor crimping maybe. I'm guessing the choke is wired to the N.C. relay contact, so that it is on when the relay is off and vise versa.

If I'm interpreting your diagram correctly, you are trying to use the alternator output to control or "fire" the relay. Bad idea. Wire the relay to the stock ignition or a toggle switch.

1). The electric choke needs to be wired into a 12V SWITCHED IGNITION source. NOT wired directly to the battery. It needs to work while the car is running, not 24/7 as you have it wired now.
2). Where are all of the red wires going that head to the alternator? I see the sense wire (red 12ga. going to the white connector) jumpered to the output post. There is also a red wire running across the top of the engine, disappearing behind the alternator, where does that go to AND come from?
3). What is the red wire running cross-car behind the carb? Is that an inline fuse holder it wire nuts too?
Mark

Thanks for the replies guys I really appreciate it.

And I was never going to keep the wiring like this, it was set up like this just to “feel” things out. That’s why I reached out to get some tips on how to wire it properly.

I really appreciate it, I will get to work on it.

Totally forgot to add that wire in. It comes from the battery as well.

Try this -
Use #1/0 battery cables
Use #10 from the alternator to the battery
Use #12 from the battery to your ignition switch “battery” terminal.
All other wire can be #14 or #16