Holley Sniper EFI Wiring - Spot Check

[MVTV]

I'm about to wire up my 427 EFI from BluePrint and looking for some feedback from those with Holley Snipers. This is by far the hardest part of the build for me.
I'm trying to keep the holley sniper controlling everything as possible.

Couple notes; no CD box, heated seats and in line fuel tank.

Here's what I plan to do based off reading threads as well as holley, RF and blueprint instructions:

Pink wire (sniper +) - Connected to sniper

Red wire (battery +)- Connected to battery positive terminal (From the main (7-pin) harness)

Black wire - (battery -) - Connected to battery negative terminal (From the main (7-pin) harness)

Thick Blue wire (fuel pump output +) - Connected to the fuel pump

Light Blue wire (Fan) - Connected to the green fan thermo switch

Yellow wire (coil input -) - Connected to the coil negative input

Orange Wire (coil +) - Connected to the coil positive input

Dark green wire (crank signal negative) - not used

Violet wire (crank signal positive) - not used

Choke wire for heated seats - haven't done enough research yet to ensure this part is right

Thanks for the help.

[RJD]

The pink wire of the Sniper 7 pin connector needs to go to a switched ignition source that remains powered during cranking. Since you have the orange wire connected to the coil positive input, that leaves the choke wire to connect to the pink wire.

I have the brown heater wire on the ACC Feed powering my seat heaters.

Bonus: If you use the Sniper to power your fuel pump, you can repurpose the Ron Francis fuel pump circuit for something else - I use it to power USB ports.

[MVTV]

Hey RJD - Thanks for the info. Good stuff! Regarding the fuel pump, how do I get the Sniper to power the fuel pump?

[FF33rod]

The Sniper comes with a wire harness and a relay embedded in it (reference pg 16 of the Sniper installation manual) with a long blue wire coming out of it. Connect that blue wire to your fuel pump positive (instead of using the RF harness). There are other methods of using the RF harness wires and relay but it gets confusing trying to describe it.

Just to clarify for the fan, I assume you mean connecting the light blue Sniper wire to the dark green wire in the RF front harness that would normally go to the thermo switch (thermo switch is now not used).


Steve

[MVTV]

Thanks on both!

[Papa]

I de-pinned the fuel pump wire from the rear harness weatherpak and connected the Sniper fuel pump wire via a single wire weatherpak. No need to run a separate wire all the way to the pump. Also, if you bypass the RF fuel pump relay this way, you'll need to reconfigure your inertia switch, since it won't do anything for you in it's current location.

[RJD]

Hey RJD - Thanks for the info. Good stuff! Regarding the fuel pump, how do I get the Sniper to power the fuel pump?

Concur with FF33Rod. I removed the Ron Francis tan fuel pump wire entirely and ran the Sniper blue fuel pump wire in its place directly to the fuel pump. The Sniper blue wire is larger gauge than the Ron Francis wire by the way.

Since I was repurposing the Ron Francis fuel pump circuit to power a USB port, I removed the Ron Francis fuel pump relay and relay control wires from the fuse panel, and then ran a wire to the USB port from the output pin of the Ron Francis fuel pump fuse.

[MVTV]

Hey Papa - To ensure I understand, de-pin (cut connection at the fuse box) the RF fuel pump wire and connect it to the sniper fuel pump wire. If I did that, then the inertia switch will operate normally and I wont need to run a separate line all the way to the fuel pump. Is that right?

Thanks in advanced!

[Papa]

Hey Papa - To ensure I understand, de-pin (cut connection at the fuse box) the RF fuel pump wire and connect it to the sniper fuel pump wire. If I did that, then the inertia switch will operate normally and I wont need to run a separate line all the way to the fuel pump. Is that right?

Thanks in advanced!

I didn't use the RF relay at all. The de-pin I was referring to was at the plug where the rear harness connects to the main harness. But, yes. If you use the RF relay the way you describe, the inertia switch will work as wired in the manual. All the inertia switch does as wired per the manual is interrupt the fuel pump relay ground.

[MVTV]

This sounds like a silly question, but I don't want to make a mistake. Regarding the 7 pin connector on the Holley Sniper, are you taking the connector apart to see all the wires or connecting directly to the 7 pin connector?

[Papa]

This sounds like a silly question, but I don't want to make a mistake. Regarding the 7 pin connector on the Holley Sniper, are you taking the connector apart to see all the wires or connecting directly to the 7 pin connector?

For each of the 7 & 10 pin connectors on the Sniper, the wires are visible. Don't open up the sealed plugs on the Sniper side, but DO de-pin the unused wires on the other side of the plug.

https://thefactoryfiveforum.com/attachment.php?attachmentid=147238&d=1620052665

https://thefactoryfiveforum.com/attachment.php?attachmentid=147239&d=1620052774

For example (your installation may vary):

On my installation using a standard coil and distributor, the only wire I needed in the 10-pin connector was for the fan control. Some may also use the tach wire, but the Speedhut tach gauge works just fine with a standard coil connection. On the 7-pin connector, I removed the crank signal wire pair (green and purple) from the plug.

https://thefactoryfiveforum.com/attachment.php?attachmentid=147245&d=1620053909

Depending on your specific ignition setup, you will need different wires in the two plugs than I needed, but should still de-pin and plug the unused wires. Holley sells a handy de-pin kit for this.

https://www.holley.com/products/fuel_systems/fuel_injection/wiring_shop/wiring_tools/parts/567-101

I saved all the wires I removed in case I ever need to re-pin the pugs for a different ignition setup.

[MVTV]

Ahhh, thank you. For some reason I kept thinking the connectors in the diagram that connect to the 7 or 10 pin connectors were from RF which is why nothing made sense. Thanks!

[Mike DiGiorgio]

thick blue wire should be an output from the fuel pump relay, double check this is in

light blue wire should go to the cooling fan relay, which can be a terminal on the thermo witch, but you do not need the switch anymore with sniper

What distributor are you using? this can change how the coil is hooked up

[JohnMac]

The wiring for the sniper can be confusing especially if you don’t read the instructions. I finally went into Holley’s web site and downloaded the instruction manual which is much longer then the one included with sniper kit. One problem we had was disconnecting the 3.5 display controller connector in order to run the 4 conductor wire through the firewall- we didn’t see the instructions and managed to pull the pins out of the throttle body’s harness. Like a lot of connectors, there’s a release on the display’s wire connector side that does the trick. The wiring when using a coil can be confusing because there are 2 wiring diagrams on 2 different pages.

[D-Dubya]

Dave,

I know this is a question from an old post but I am looking at how to wire up my Sniper on a BPE 347 and I can see how the inertia switch is rendered useless when not using the tan wire to the fuel pump or the fuel pump relay in the RF fuse block. That said, how else can you wire the inertia switch? I apologize but electrical is not my strong suit. Thanks in advance for your help.

Doug

[Papa]

Dave,

I know this is a question from an old post but I am looking at how to wire up my Sniper on a BPE 347 and I can see how the inertia switch is rendered useless when not using the tan wire to the fuel pump or the fuel pump relay in the RF fuse block. That said, how else can you wire the inertia switch? I apologize but electrical is not my strong suit. Thanks in advance for your help.

Doug

The easiest way to include the inertia switch is to place it in the ground circuit for either the Sniper itself or the fuel pump. I'd recommend the latter of those two options. To do that, you'll want the rear harness ground after any splices to have the inertia switch in the run. You can mount the inertia switch in the trunk to shorten the run and provide easy access in a clean, dry environment. Simply cut the ground wire a few inches from the plug that snaps onto the fuel pickup and connect the harness side to one end of the inertia switch and then connect the other end to the fuel pump plug/connector.

Dave

[first time builder]

Make sure the sniper red and black go directly to the battery.