2 Fuel Pumps

[SGT_MERC]

What's the easiest and safest way to set a second in tank fuel pump to come on with boost?

[Zack]

A Hobbs switch set at 3-5 psi
eBay all day long for that

[SGT_MERC]

A Hobbs switch set at 3-5 psi
eBay all day long for that

How do I wire it up?

[SGT_MERC]

Really? No one wants to tell me? Any other question and there'd be 10 members falling all over each other trying to answer.

[massacre]

A Hobbs switch set at 3-5 psi
eBay all day long for that

I deal with Hobbs switches daily in my job.
A Hobbs switch is a switch that either turns an air signal into an electrical signal, or an electrical signal into an air signal, we use both types as well as Clippard and shuttle valves to direct airflow under a variety of conditions.
A Hobbs switch is usually used as an air over electric switch which means the elec part of the switch is normally closed until the switch sees a certain air pressure, then it sends an electrical signal.

Wait are you a CVN member?

[SGT_MERC]

Yes.....Same user name

[chief455]

How do I wire it up?
it has a vacuum/boost nipple in. 2 electric spades = in/out.
the source to vacuum = manifold
1 spade to 12v+ source, other spade to fuel pump +

When manifold pressure is above set psi the Hobbs triggers power to your fuel pump.

look carefully when buying the Hobbs switch - most being sold are 10psi or higher, when I was shopping.
Be sure it is either adjustable, low pressure as Zack said, or fixed rated low pressure.
I used a 1psi switch, so my second pump is activated with boost, period.

Top Tip:
I also made my pumps able to be alternated primary/secondary by just swapping the power feed wires.
Allows you to rest your primary pump after one season, let it be the boost pump.
I also made it so should my primary pump show low fuel pressure, jump the Hobbs switch spades with a pre made jumper wire, and the secondary pump will get you home.

[SGT_MERC]

Thank You for the info.

[chief455]

Thank You for the info.
It is perfet for adding the volume needed during boost to reduce detnoation risk, lean condition a WOT. I also liked the jumper wire trick on the switch to turn on 2nd pump in emergency. I used it first day out on roadside. nice easy install.
good luck

[SGT_MERC]

It is perfet for adding the volume needed during boost to reduce detnoation risk, lean condition a WOT. I also liked the jumper wire trick on the switch to turn on 2nd pump in emergency. I used it first day out on roadside. nice easy install.
good luck

Thank You. I'm just terrible at wiring because of my color vision. I have to label everything and run one wire at a time. Very time consuming.

[Zack]

When running 2 pumps, always use this wiring kit.
http://api.viglink.com/api/click?format=go&jsonp=vglnk_jsonp_139308688717 510&key=a79e31547a0cb25c7522b74256 c3eea0&loc=http%3A%2F%2Fwww.thechicag ogarage.com%2Fforum%2Fmarauder-tech%2F119317-wiring-additional-fuel-pumps.html&v=1&libId=d92cd754-caaf-4b6d-b222-51f27f292424&out=http%3A%2F%2Fwww.racetroni x.biz%2Fitemdesc.asp%3Fic%3DBC WS-001%26eq%3D%26Tp%3D&ref=http%3A%2F%2Fwww.google.co m%2Furl%3Fsa%3Dt%26rct%3Dj%26q %3D%26esrc%3Ds%26source%3Dweb% 26cd%3D1%26ved%3D0CCYQFjAA%26u rl%3Dhttp%253A%252F%252Fwww.th echicagogarage.com%252Fforum%2 52Fmarauder-tech%252F119317-wiring-additional-fuel-pumps.html%26ei%3DmtEIU7maN6Tu yQH84YHYCA%26usg%3DAFQjCNGfXEO hKaOkdE4vSa_5Oe6-p9ZgOQ&title=Wiring%20for%20Additiona l%20Fuel%20Pumps%20-%20TCG&txt=Racetronix%20-%20Universal%20Bulkhead%20Wiri ng%20System%2C%204-Way
http://www.racetronix.biz/mmWEBSTORE/Images/bwcs-001.jpg

And remember if you have a return style fuel system (you must since you are triggering a second pump) NEVER let the fuel drop even near 1/4. It will suck the basket dry at the bottom of the tank.

[SGT_MERC]

When running 2 pumps, always use this wiring kit.
http://api.viglink.com/api/click?format=go&jsonp=vglnk_jsonp_139308688717 510&key=a79e31547a0cb25c7522b74256 c3eea0&loc=http%3A%2F%2Fwww.thechicag ogarage.com%2Fforum%2Fmarauder-tech%2F119317-wiring-additional-fuel-pumps.html&v=1&libId=d92cd754-caaf-4b6d-b222-51f27f292424&out=http%3A%2F%2Fwww.racetroni x.biz%2Fitemdesc.asp%3Fic%3DBC WS-001%26eq%3D%26Tp%3D&ref=http%3A%2F%2Fwww.google.co m%2Furl%3Fsa%3Dt%26rct%3Dj%26q %3D%26esrc%3Ds%26source%3Dweb% 26cd%3D1%26ved%3D0CCYQFjAA%26u rl%3Dhttp%253A%252F%252Fwww.th echicagogarage.com%252Fforum%2 52Fmarauder-tech%252F119317-wiring-additional-fuel-pumps.html%26ei%3DmtEIU7maN6Tu yQH84YHYCA%26usg%3DAFQjCNGfXEO hKaOkdE4vSa_5Oe6-p9ZgOQ&title=Wiring%20for%20Additiona l%20Fuel%20Pumps%20-%20TCG&txt=Racetronix%20-%20Universal%20Bulkhead%20Wiri ng%20System%2C%204-Way
http://www.racetronix.biz/mmWEBSTORE/Images/bwcs-001.jpg

And remember if you have a return style fuel system (you must since you are triggering a second pump) NEVER let the fuel drop even near 1/4. It will suck the basket dry at the bottom of the tank.

Thank You. How low does the tank have to be before I remove the fuel hat?

[Zack]

Thank You. How low does the tank have to be before I remove the fuel hat?

You don't have to unbolt the tank.

I cut the wiring harness that goes toward the passenger side. Then I use a 3 wire weatherproof connector I get from the boneyard and solder it on. It makes for very easy removal in the future.

[chief455]

When running 2 pumps, always use this wiring kit.

And remember if you have a return style fuel system (you must since you are triggering a second pump) NEVER let the fuel drop even near 1/4. It will suck the basket dry at the bottom of the tank.
Exactly what I used, Racetronix hotwire kit for fuel pump (with relay) for each pump. And I keep 1/2 tank to never let the pumps be exposed from fuel - good tips :)

It's not hard to do SGT_MERC, once it's in your hands.

[SGT_MERC]

Thank you gentleman. I'll be starting it soon.

[Zack]

Do you have MM_BKK's old car?

[SGT_MERC]

Do you have MM_BKK's old car?

Yes I do. It's been an ongoing work in progress

[SGT_MERC]

How do I get the wires of the racetronix kit through the fuel hat grommet and have a proper seal? It way be a stupid question, but I need to ask.

[chief455]

How do I get the wires of the racetronix kit through the fuel hat grommet and have a proper seal? It way be a stupid question, but I need to ask.
not the Marauder hat, but hope these help

[SGT_MERC]

That really didn't help me much, sorry.

[Blown3.8]

You need to drill a hole. Leave the factory wire in place.

[chief455]

That really didn't help me much, sorry.
Sorry about that.
We used hard plastic (white), cut it to fit shape of hat, drilled holes for red positive wires to pass through, made same shape gasket and bolted this to the hat. Applied fuel resistent sealer between gasket and plastic, then around wires passing through.
Again, this is not the Merc hat, just a solution that worked on another 2 positive wire pump set up.
I'm sure someone will show you a Merc set up.

[SGT_MERC]

What type of fuel resistant sealer did you use? Is there a special type of grommet I'll need to use, that's fuel resistant, to pass the wires through the hat?

[Zack]

What type of fuel resistant sealer did you use? Is there a special type of grommet I'll need to use, that's fuel resistant, to pass the wires through the hat?

Buy the racetronix kit I posted.

[massacre]

At work I use one of these to mark all of my wiring/hoses, I do a lot of small air hoses that are all painted the same color so impossible to tell them apart once they are removed:
http://www.skygeek.com/3m-scotchcode-wire-marker-tape-dispenser-std-0-9.html?utm_source=googlebase&utm_medium=shoppingengine&utm_content=3m-scotchcode-wire-marker-tape-dispenser-std-0-9&utm_campaign=froogle&gclid=CN754Z6Wz70CFQHKpAodiwEA AQ

It may help you since you said you are color blind.

[SGT_MERC]

Buy the racetronix kit I posted.

Do you have a pic of what the racetronix kit going into the marauder fuel hat? It would be nice to have something to refer to before I buy it. I want to buy the kit, but I need to be sure it's something I can do myself.

[Blown3.8]

Its very easy to install. Just drill a hole and it snaps in with a clip. Looks kinda like the pic of the yellow connector a few posts up.

[SGT_MERC]

Thank You everyone for your advice and info. Now I can blame everyone else instead of just me. LMAO, Just Kidding.

[SGT_MERC]

When running 2 pumps, always use this wiring kit.
http://api.viglink.com/api/click?format=go&jsonp=vglnk_jsonp_139308688717 510&key=a79e31547a0cb25c7522b74256 c3eea0&loc=http%3A%2F%2Fwww.thechicag ogarage.com%2Fforum%2Fmarauder-tech%2F119317-wiring-additional-fuel-pumps.html&v=1&libId=d92cd754-caaf-4b6d-b222-51f27f292424&out=http%3A%2F%2Fwww.racetroni x.biz%2Fitemdesc.asp%3Fic%3DBC WS-001%26eq%3D%26Tp%3D&ref=http%3A%2F%2Fwww.google.co m%2Furl%3Fsa%3Dt%26rct%3Dj%26q %3D%26esrc%3Ds%26source%3Dweb% 26cd%3D1%26ved%3D0CCYQFjAA%26u rl%3Dhttp%253A%252F%252Fwww.th echicagogarage.com%252Fforum%2 52Fmarauder-tech%252F119317-wiring-additional-fuel-pumps.html%26ei%3DmtEIU7maN6Tu yQH84YHYCA%26usg%3DAFQjCNGfXEO hKaOkdE4vSa_5Oe6-p9ZgOQ&title=Wiring%20for%20Additiona l%20Fuel%20Pumps%20-%20TCG&txt=Racetronix%20-%20Universal%20Bulkhead%20Wiri ng%20System%2C%204-Way
http://www.racetronix.biz/mmWEBSTORE/Images/bwcs-001.jpg

And remember if you have a return style fuel system (you must since you are triggering a second pump) NEVER let the fuel drop even near 1/4. It will suck the basket dry at the bottom of the tank.
Thank You btw for pointing me in the right direction.