Sniper 2 + RF Wiring Help

[Dondero14]

Hello all. I've tried to do as much research as possible with the engine wiring but want to be fully sure that I'm doing everything correctly because I'm extremely green when it comes to car wiring. I have a Blueprint 347 engine with the Holley Sniper 2 EFI. The idea I have for the following wiring is so:

1. RF Orange Coil or EFI wire to the (+) Coil
2. Sniper 2 Yellow Wire to the (-) Coil
3. RF Purple Coil --> Tach connected to ??? I've read mostly that this also gets connected to the coil. Should it be the (+) or (-) terminal if so. I'm not running a hyper spark or any MSD setup.

4. ***Sniper 2 Pink Wire ??? I've seen some posts about connecting this to the tan electric choke and have seen this spliced into the orange coil wire (not to keen about connecting to the coil wire). Is there a reason not to just go directly to the ignition switch with the pink wire? It says in the Sniper 2 manual in Bold letters and underlined NOT to connect to a source with other components that pull high currents, such as the ignition coil or starter solenoid.

5. RF Blue EFI Crank wire??? What is this wire suppose to be connected to if anything?

Lastly, I was planning on running the Sniper 2 Yellow wire, RF Purple Tach wire, and the RF Orange Coil wire in a single loom together to the coil. I was told by a Holley tech when asking a wiring question that the yellow wire shouldn't be in the same loom as other ignition sources. Does that mean that its not a good idea to have it in the same loom as the RF Orange Coil wire since that is an ignition wire or an ignition source such as near the headers?

[BUDFIVE]

Dondero, I just converted my car from carb to Sniper 2 with the RF Harness. Here’s a cut and paste from the wiring paragraph in post #145 in my build thread. So, Q1 and Q2 look good. Q3 on purple tach wire-I have an electronic distributor with a tach output so I’m not 100% sure for you but I think you connect to the negative side of coil (Others Comment?). Q4 on the pink wire-I connected to the tan choke wire as my notes say-the important part is the pink goes to a switched source that is hot in the ignition Run and Crank positions, which the tan is. Q5–Blue Crank wire-I didnt use this wire-I dont think Sniper 2 uses a crank wire, rather it watches coil pulses to detect a crank.

I also recommend you think about if you want to use the Sniper to trigger the cooling fan (I did) and to trigger the fuel pump (I havent yet). If your Sniper harness has a fuel pump relay (harness 558-191) you can use the Sniper relay or the RF relay. If not (harness 558-190) you can use the sniper blue fuel pump wire to trigger the RF relay. Note the cooling fan relay and the fuel pump relay are ground triggers. I (and others) can help with these once you tell us how you want them to work.

Hope this helps-

Build thread link-

https://thefactoryfiveforum.com/showthread.php?47734-BUDFIVE%92s-CenTex-Build-Rivet-Painted-Door-Sills-amp-3D-Access-Covers/page4

From post #145:
Wiring (similar to forum member posts, thanks Papa, others)-
-Dedicated Sniper 2 connector to CTS.
-Dedicated Sniper 2 connector to WB-O2
-16 pin connector to 558-190 Main Harness. wires:
-Red 12 ga power to Master kill switch ON bus, closest to 2 ga battery+.
-Black 12 ga ground to 2 ga battery- cable at frame.
-Pink switched 12v to RF sending unit harness tan choke wire. RF orange coil/EFI wire remains on coil+.
-Yellow coil- wire to - post on coil for synchronization, rpm.
-Blue fuel pump trigger temporarily capped with heat shrink. Not using Sniper for fuel pump control, yet.
-Black/yellow wire in 6 pin I/o harness to RF sending unit harness dark green. This is user programmable Fan 1
output ground trigger wire.
-All other unused wires capped with heat shrink.

[PMD24]

Mark, below are some specifics on your questions based on what I did. Some of these can be done differently and still be fine. The details below worked for prelim wiring for first start and yesterday I did another start after many hours of removing unused wires and doing cleanup. Still worked fine. Responses should show in red/

1. RF Orange Coil or EFI wire to the (+) Coil Correct
2. Sniper 2 Yellow Wire to the (-) Coil Correct
3. RF Purple Coil --> Tach connected to ??? I've read mostly that this also gets connected to the coil. Should it be the (+) or (-) terminal if so. I'm not running a hyper spark or any MSD setup. I did not use this wire. I have the Vintage Gauges and took the yellow gauge wire to coil (-). If you choose to do this you can combine this wire and the EFI yellow wire in a single connector to the coil. Or, you can bring one wire from coil (-) behind the dash and combine them there. For my preliminary wiring I combined them at the coil. For final I'll probably combine them behind the dash.

4. ***Sniper 2 Pink Wire ??? I've seen some posts about connecting this to the tan electric choke and have seen this spliced into the orange coil wire (not to keen about connecting to the coil wire). Is there a reason not to just go directly to the ignition switch with the pink wire? It says in the Sniper 2 manual in Bold letters and underlined NOT to connect to a source with other components that pull high currents, such as the ignition coil or starter solenoid. S2 Pink to RF tan electric choke is standard protocol. It is not a high current wire. Load on the pink will be very small. It's simply powering the EFI "computer".

5. RF Blue EFI Crank wire??? What is this wire suppose to be connected to if anything? Not used

Lastly, I was planning on running the Sniper 2 Yellow wire, RF Purple Tach wire, and the RF Orange Coil wire in a single loom together to the coil. I was told by a Holley tech when asking a wiring question that the yellow wire shouldn't be in the same loom as other ignition sources. Does that mean that its not a good idea to have it in the same loom as the RF Orange Coil wire since that is an ignition wire or an ignition source such as near the headers? I ran the tach wires in their own 1/4" loom through the intake valley, along with the orange coil wire. They are not ignition sources. ignition sources would be the distributor and spark plug primary wiring.

Pat

[Dondero14]

Thanks a ton Pat and BUDFIVE for the guidance. I'll plan on tapping into the RF tan electric choke wire to connect the Sniper 2 pink wire to and connect the RF Purple tach wire and Sniper 2 yellow wire together into the same connection at the coil. Only a few weeks away from firing the engine up and I just wanna be sure I have everything correct the first time as best as I can.

[Dondero14]

I also recommend you think about if you want to use the Sniper to trigger the cooling fan (I did) and to trigger the fuel pump (I havent yet). If your Sniper harness has a fuel pump relay (harness 558-191) you can use the Sniper relay or the RF relay. If not (harness 558-190) you can use the sniper blue fuel pump wire to trigger the RF relay. Note the cooling fan relay and the fuel pump relay are ground triggers. I (and others) can help with these once you tell us how you want them to work.

BUDFIVE what is the advantage to wiring up the fuel pump and the cooling fan relay into the Sniper 2 wiring harness? I considered the fuel pump but also didn't feel like running the extra wire and changing things around with the inertia switch since it was already wired up. Is it more so to free up wires and fuses in the RF setup?

[BUDFIVE]

Dondero-
1) Fuel Pump-I haven’t done this yet. With RF harness and normal FFR install the fuel pump relay is triggered (grounded) by the inertial cutoff switch output. If the inertia switch is tripped, it is an open circuit and the pump is off. If the ignition is On, and the inertia switch is closed which grounds the switch output, the fuel pump input is triggered and runs As Long As The Key Is On. If you connect the inertia switch to the Sniper Blue Fuel Pump trigger (instead of ground) when you turn they key on, the Sniper runs the pump only for a few seconds then cuts off unless you start the engine. This will be nice while programming the Sniper or saving Sniper config files which require the ignition on. For now, my pump runs and runs while the ignition is on, kind off a pain. I will either use the Sniper blue wire functionality or a spare toggle on my dash in the near future.

2) Coolant fan-the RF harness uses a 1-wire sensor, usually in the thermostat housing, which is an open or closed circuit based on temperature. Even though they are reasonably accurate, these sensors are not adjustable. For example, the sensor may stay open until the coolant reaches 200 F then close, which grounds the switch terminal through the sensor body, triggering the fan relay. The example sensor may then stay closed until the coolant goes back down to 190 when it opens. This 10 degree overlap hysteresis keeps the fan from kicking on and off every time the temp fluctuates a little. If you use the Sniper 2 yellow/black* wire in the I/o harness as the fan relay ground trigger it is programable. The fan On and fan Off set points are programmed in the Sniper I/O settings menu.This allows you to program the set points away from the thermostat temp so the fan doesnt run all the time, or only at stop lights, or with more/less than 10 degrees of hysteresis, for examples. This works great on my build.
*The Sniper yellow/black I/O must trigger a relay. The I/O pin cant sink enough current to run the fan and will be damaged if connected directly to the fan.

[Dondero14]

Awesome thank you a ton for the thorough explanation. Definitely helps me understand the reasonings a lot better. Will probably keep things as is for now until I get everything up and running but will absolutely keep in mind down the line.