Holley sniper fuel tank help!

[BrandonTobia_773]

Hey guys! So I’m installing a Holley sniper on my 87 v10 and I bought 2 new tanks and pumps and sending units, after getting the new tanks all setup and put together I’m haveing a hard time figuring out how to wire it all in since the original pump/ sending unit was just a 2 wire setup and all in one compared to now the sending unit and pump are wired separately… anybody have any pictures of how they are wired in? Thank you!

 

[Bextreme04]

The original setup would send power to the switching valve to switch tanks. I would use a dual relay setup. The first relay will make sure the pumps are only running when the engine is running or ignition is on. The second relay would be used to power the individual pumps and can be used to switch the power to the pumps by splicing the actuation power for the relay into the power wire to the switching valve. So, pin 30 straight to the battery with 10awg wire. pin 87 to one pump. Pin 87a to the other pump. Pin 86 to the switching valve wire and Pin 85 straight to a clean ground point on the frame.

You will need to figure out which tank is actively being used on the switching valve with no power applied to the valve. That is the tank that should have its pump wired to Pin 87A.

You can make the first relay as smart or as dumb as you want. There are also some special boxes out there that will make it so it will do a 2 second prime on initial power on and then only run the pump when the box sees engine RPM(just like a factory fuel injection would do) so that if you have an accident or rollover the pump doesn't just run continuously.

@Catbox had an amazon link to a pretty decent one of those. If you used that you would use that to power the relay that you use to switch pumps.

 

[Catbox]

This is the safety device Eric speaks of

https://www.amazon.com/dp/B00BNZ05JM/

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[BrandonTobia_773]

And run 2 of the safety relays? One for each pump correct? And thank you for the help!

 

[Bextreme04]

And run 2 of the safety relays? One for each pump correct? And thank you for the help!

I would use one of those safety switches to feed a relay to switch between the two pumps. The relay would switch between the pumps when the switching valve is actuated and the safety switch would provide the priming pulse and power the relay at the appropriate times based on engine rpm and ignition switch position. Or alternatively, two relays but the safety switch triggers one relay and the second relay changes the feed between the two pumps. The determination on whether you want two relays would be based on the power draw you expect from the pump you installed.

 

[87 Scottie]

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