fuel pump power source?

[Wizo]

Hey guys: I am currently wiring the engine compartment of my truck. This question is for you guys running an external fuel pump. What switchable power source are you guys using to power the fuel pump. Im kinda technically minded so if you could be specify it would help me a lot. thanks in advance.

[texasld]

Originally Posted by Wizo

Hey guys: I am currently wiring the engine compartment of my truck. This question is for you guys running an external fuel pump. What switchable power source are you guys using to power the fuel pump. Im kinda technically minded so if you could be specify it would help me a lot. thanks in advance.

If you are using a new wiring harness, it should have a lead for a fuel pump. If not, any key switched 12v feed would work. If you have an open circuit, that would work too! Just make sure it's switched with the key. Constant would drain the battery.

[Wizo]

thanks but, I've looked and looked and looked But there isn't one on there specifically for a fuel pump. That's why I was wondering what you guys are using for a switchable power source. Like specifically which pin on the bulkhead connector?

[davepl]

I would run a dedicated heavier gauge wire from the battery (or junction box) back to the pump. Then a relay between it and the pump. I would then use the fusebox "IGN UNFUSED" terminal to trigger the relay. You can hide a kill switch while you're at it if you so choose. This can be small gauge because it's just triggering the relay.

The heavy gauge power wire must have a fuse. A circuit breaker would be the alternative I'd use as you need the pump to get you home, and that's how they did it with headlights, so I'd follow the factory lead there.

I would also highly recommend, at a minimum, a cheap Ford collision interrupt. You can get them on eBay cheap. If you're in a wreck it pops a button up like a breaker so the pump doesn't prepare you for immolation.

As for me, I went one further. I have the crash sensor and I also bought a GM "lift pump" relay kit for a Duramax. It serves two purposes:

1) When the key is first turned on it runs for 10 seconds or so to fill the carb bowl(s) and then turns off so it's not annoying you all the time

2) When it sees an RPM signal it turns on.

3) When it loses an RPM signal it turns off.

That's how the factory wires them, and that's how you should too.

[davepl]

One edit: I think the lift pump looks at oil pressure, not RPM.

As for collision sensor, this isn't the same one I have, but it's close:

http://www.ebay.com/itm/MUSTANG-Cras...b73122&vxp=mtr

The fancy delay relay kit is intended for the Duramax lift pump. Not sure which one it is, but Kennedy Diesel sells them I believe:

http://www.kennedydiesel.com/categor...bCategory2=127

[texasld]

Originally Posted by davepl

I would run a dedicated heavier gauge wire from the battery (or junction box) back to the pump. Then a relay between it and the pump. I would then use the fusebox "IGN UNFUSED" terminal to trigger the relay. You can hide a kill switch while you're at it if you so choose. This can be small gauge because it's just triggering the relay.

The heavy gauge power wire must have a fuse. A circuit breaker would be the alternative I'd use as you need the pump to get you home, and that's how they did it with headlights, so I'd follow the factory lead there.

I would also highly recommend, at a minimum, a cheap Ford collision interrupt. You can get them on eBay cheap. If you're in a wreck it pops a button up like a breaker so the pump doesn't prepare you for immolation.

As for me, I went one further. I have the crash sensor and I also bought a GM "lift pump" relay kit for a Duramax. It serves two purposes:

1) When the key is first turned on it runs for 10 seconds or so to fill the carb bowl(s) and then turns off so it's not annoying you all the time

2) When it sees an RPM signal it turns on.

3) When it loses an RPM signal it turns off.

That's how the factory wires them, and that's how you should too.

^^ This is an even better way to go about it!

[Wizo]

Thanks Dave. You have given me plenty of food for thought. I'm liking the direction that you went. I don't suppose you have the part number for the Lift pump relay kit for Duramax that you used?

[texasld]

Originally Posted by davepl

One edit: I think the lift pump looks at oil pressure, not RPM.

As for collision sensor, this isn't the same one I have, but it's close:

http://www.ebay.com/itm/MUSTANG-Cras...b73122&vxp=mtr

I worked on a Ford Exploder at one point in time. I know it had one in the upper section of the passenger foot well. You may be able to catch one at a junk yard no problem. That's almost on of those "Ahh He!!, you can just take that, it's not worth my time" type deal.

[87Skier]

Originally Posted by davepl

I would run a dedicated heavier gauge wire from the battery (or junction box) back to the pump. Then a relay between it and the pump. I would then use the fusebox "IGN UNFUSED" terminal to trigger the relay. You can hide a kill switch while you're at it if you so choose. This can be small gauge because it's just triggering the relay.

The heavy gauge power wire must have a fuse. A circuit breaker would be the alternative I'd use as you need the pump to get you home, and that's how they did it with headlights, so I'd follow the factory lead there.

I would also highly recommend, at a minimum, a cheap Ford collision interrupt. You can get them on eBay cheap. If you're in a wreck it pops a button up like a breaker so the pump doesn't prepare you for immolation.

As for me, I went one further. I have the crash sensor and I also bought a GM "lift pump" relay kit for a Duramax. It serves two purposes:

1) When the key is first turned on it runs for 10 seconds or so to fill the carb bowl(s) and then turns off so it's not annoying you all the time

2) When it sees an RPM signal it turns on.

3) When it loses an RPM signal it turns off.

That's how the factory wires them, and that's how you should too.

Thanks! I will be adding this to my to do list. I currently have mine setup to switch on when the key turns on.

If you guys are using the factory bulk head/fuse box, its actually really easy to wire in more stuff. I added a switched wire in the engine harness and ran it with the body harness to the battery and added a fuse/relay box there.

[Fitz]

Originally Posted by Wizo

Hey guys: I am currently wiring the engine compartment of my truck. This question is for you guys running an external fuel pump. What switchable power source are you guys using to power the fuel pump. Im kinda technically minded so if you could be specify it would help me a lot. thanks in advance.

Tie a 12 GA wire from IGN UNFUSED to pin 85 on a 12 volt relay. Pin 30 goes to a 30 A fuse then battery. 87 goes to the pump. 86 to ground. Be SURE to use a 30A relay and fuse the battery side. Most electric pumps have a high surge at start then current drops down to a lower level so , unless you want to walk to the nearest parts store, use a 30 A fuse as well. I ran 8 Ga wire for the pump as it is next to the tank located behind the differential. An in-cab tank would be OK with 10 ga. If your cab is well grounded to the frame you can use 12 Ga for both grounds as those runs will be shorter than 1 foot. You can get battery at the starter. I did not use that point as I use a separate fusebox under my dash with a 6 Ga run to battery to power vacuum pump, fuel pump, and twin electric fans.

[Fitz]

Originally Posted by Wizo

Hey guys: I am currently wiring the engine compartment of my truck. This question is for you guys running an external fuel pump. What switchable power source are you guys using to power the fuel pump. Im kinda technically minded so if you could be specify it would help me a lot. thanks in advance.

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