power for electric fuel pumps ?
 

Hey guys im drawing from my coil for my electric fuel pumps. 12 volts. Is this the wrong power source? Could this cause a week ignition ?

Re: power for electric fuel pumps ?
 

Is the 12v wire going to the coil able to handle the extra load on it now? If anything, I would think a relay that got it's signal from the coil would be better. Thus allowing you to pull a dedicated lead for the pumps from elsewhere.

Re: power for electric fuel pumps ?
 

Yes. Here is what I did. Use a pressure switch that makes when you have oil pressure. Feed it with 12 volts and use the output to fire a relay that will switch a good power source to the fuel pump. Lose oil pressure or someone turns the key on you have no fuel pump. If need be you can jump the pressure switch to fill the float bowl but this has never been a problem for me. There are pressure switches that will only make when cranking or when there is enough pressure to close them. In any case use a relay to source good power to the pump.

Re: power for electric fuel pumps ?
 

I went to electric fuel pumps last summer. When I connected them up I did the same and took power from the purple wire at the coil. I burned out both pumps within a 1/2 hr. It was an expensive lesson...

The best way is with a relay and direct power from the battery.

Re: power for electric fuel pumps ?
 

Kurt, you should really be running the pumps from contuous-duty relays or solenoids, along with an oil pressure switch wired with a starter bypass.
When I bought my Cigarette the pumps were wired to the positive coil post on the Thunderbolt ignition and I had intermittent ignition operation a few times.

Re: power for electric fuel pumps ?
 

Yup, never hook to the coil for power, the coil or the fuel pump will die a horrible death-and quickly too. A relay and a pressure switch is the best set up.

Re: power for electric fuel pumps ?
 

Where do you draw the power for the relay?

Re: power for electric fuel pumps ?
 

Connect the relay directly to the battery or main starter terminal, using a fuse or circuit breaker sized accordingly for the load.

Re: power for electric fuel pumps ?
 

Or the common post on your battery switch.

Re: power for electric fuel pumps ?
 

The ignition ( purple) wire should be isolated to only fire a solid state relay( most dependable in the marine environment). The ground for the relay should be tapped into a oil pressure regulated hop switch. Relay primary leads should be of 10 ga. and signal leads of 14ga. all of tinned copper. Figure in your resettable breaker, and you'll have a very efficient and trouble free circuit.

Re: power for electric fuel pumps ?
 

thanks for the help fellows

Where do i get the correct relay?? I need two of them, i bought a boat and it was hooked to the purple wire of the coil. I want it changed to be correct.

if you connect the relay directly to the battery wont the pump run all the time? And how do i wire it into the oil preassure switch?

The relay will only let electric go to your fuel pump when it gets juice from the coils or ignition switch or oil pressure sending unit, whatever, to close the contacts. A relay is just a switch. You "turn on" that switch by supplying electric to it instead of manually moving a toggle or pushing a button. The power that runs the fuel pump is separate from the power that causes the contacts in the relay to close (and make the fuel pump turn on). I know that's not very clear, but I hope that helps...anyone else wanna try?

summit racing
 

get one for summit racing and a 7lb oil switch its simple set up cost you 50 bucks to youre door

Can i hook the oil pressure switch to my external oil filter. It has a spot on the bracket that i could use for the switch. This should have preasure here.

You should be able to put your switch there. I put my oil temp gauge there myself and screwed my oil pressure switch into the back of the block by the distributor. My oil pressure sending unit is located by the oil filter bose where the remote lines hook up to come up to the filter. Someone may chime in on what side of the filter to put it on.

Good Luck!!

The block where there is like a 1/4" plug? I have a oil switch but i think i fried it.... Can you blow air into the oil safty switch to make it trip? I had it all hooked up and grounded and i was trying to make it trip the relay but couldnt

Actually i am looking at the intake manifold where there is a plug near the distributer.

my electric fuel pump quite working out on the water. took it off because i thought it burned up after running it off the coil, but it works now when i hook it to the battery. I have perfect 12 volts at my hookup on the boat. Can fuel pumps overheat and then work again?