Tan choke wire in RF harness suitable for EFI?

[Windsorpower]

Looking to provide a clean source of switch 12v power to the red/white wire in my Holley terminator. This tan choke wire should be suitable, right?

[Mike.Bray]

Nope. Use the orange EFI/Coil wire.

[Windsorpower]

Nope. Use the orange EFI/Coil wire.

Thanks. Any reason not to put it on a post on the keyed ignition switch? It already has an eyelet on it from Holley.

[Mike.Bray]

The orange wire is fused and hot during cranking which is very important. Don't ask me how I know:)

[Windsorpower]

The orange wire is fused and hot during cranking which is very important. Don't ask me how I know:)

My MSD also has a requirement for switched 12V. Should I use the same orange wire?

[Mike.Bray]

I would.

[Valkster]

We have an Edelbrock ProFlo4 in our build and used the orange wire, and I think the light blue (it was a separate wire needed on our EFI if I am not mistaken). I am going by months-ago memory. We had no issues when we brought the engine to life.

[edwardb]

The choke wire in the RF harness is a 10amp ignition switched circuit, exactly the same as the EFI/Coil except that it's 15amp. If 10amps is enough, no reason not to use it. I used it for the Ignition Relay Trigger on my Coupe Coyote build. Works fine. I wouldn't connect directly to the ignition switch unless you have a downstream fuse or breaker.

[cv2065]

My MSD also has a requirement for switched 12V. Should I use the same orange wire?

I did...

[Jeff Kleiner]

I think you'll find that the tan "electric choke" wire is only hot when the ignition switch is in the run position but not while cranking. If your EFI doesn't have another source of power when cranking you'll need to supply it which is what the light blue "EFI Crank" wire is for.

Jeff

[Mike.Bray]

I think you'll find that the tan "electric choke" wire is only hot when the ignition switch is in the run position but not while cranking. If your EFI doesn't have another source of power when cranking you'll need to supply it which is what the light blue "EFI Crank" wire is for.

Jeff

If you don't have 12V to the ECU and ignition system during cranking it's not going to start. Speaking from experience here.

[edwardb]

I think you'll find that the tan "electric choke" wire is only hot when the ignition switch is in the run position but not while cranking. If your EFI doesn't have another source of power when cranking you'll need to supply it which is what the light blue "EFI Crank" wire is for.

Jeff


If you don't have 12V to the ECU and ignition system during cranking it's not going to start. Speaking from experience here.

The choke circuit in the Ron Francis harness is in the same IGN FEED block as the EFI circuit. Both are on during run and start. As I mentioned in my previous post, I wired the Coyote Ignition Relay Trigger wire in my Coupe build to the choke wire. It works perfectly. The Coyote won't start or run unless there's constant +12V to the Ignition Relay Trigger wire. FWIW, my reason for doing that was the choke wire is 10amps. More than enough for the Coyote trigger. I used the EFI wire for the heated seats since it's 15amps. From the RF wiring harness diagram:

210977

[Windsorpower]

Thanks everyone. I ended up using the orange EFI to power the switched 12 volt trigger for both the Holley Terminator and the MSD box. The car started on the very first attempt with no leaks and no smoke.

I’m not happy with the speedhut gauges cycling after each episode of cranking. It takes several seconds for the oil pressure gauge to finish its full sweep. I’d rather see the oil pressure immediately so I think I’m going to feed all the gauges with the tan choke wire. Thoughts?

[edwardb]

Thanks everyone. I ended up using the orange EFI to power the switched 12 volt trigger for both the Holley Terminator and the MSD box. The car started on the very first attempt with no leaks and no smoke.

I’m not happy with the speedhut gauges cycling after each episode of cranking. It takes several seconds for the oil pressure gauge to finish its full sweep. I’d rather see the oil pressure immediately so I think I’m going to feed all the gauges with the tan choke wire. Thoughts?

The gauges, radio, heater, and wiper circuits are all in the ACC FED portion of the RF fuse panel and are switched off by design when the key is in the start position. The idea is to preserve maximum starting current. While the draw on the electronic gauges is low, it does add up and defeats the purpose. I've had Speedhut gauges on several builds, including my current Gen 3 Coupe, and agree they do sweep down and then back up when you release the starter, I question "several seconds." It's pretty quick. I would maintain that once you have the car properly and reliably tuned to where it starts easily and stays running without repeated cranking, you won't notice it. For my Coupe, by the time it starts and I take my finger off the start button and then look over at the gauges they're all where they should be. It's quick and a non-issue. I wouldn't change it.