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Electric fuel pump

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eastkimberley

Member
"i have just about finished in

"i have just about finished instaling my new 5.7 vortec engine that replaces my 5l AQ231A
the old motor had a mechanical fuel pump and the new one has a electric fuel pump. what is the best way to wire this up ,is using a feed of the purple ingition wire the way to go or is there a beter way to power the pump
Thanks
Phil"
 
"Well, the 231 already has a l

"Well, the 231 already has a lot of stuff coming off the purple wire. You didn't mention how the new engine is hooked up. The power supply for all this is the ignition switch from which the "I" side is connected to a fuze and from there to the wire. If you do this, the "purple wire" fuze should be upgraded to higher amp level. I suspect that the switch can handle the extra juice without problem. However, anything over 15- 20 amps is a flag for a long run of AWG-14 if I remember correctly."
 
"you should have the pump on a

"you should have the pump on a relay, and the relay acuatuated by oil pressure, this is a failsafe if the engine dies that the electric pump does also. u can use a T at your sending unit and get a switch from napa. with the relay your spark protected also. just my 2 cents"
 
"I don't like electric pum

"I don't like electric pumps in a marine engine. However, those that do like to point to the fact that fuel pressure builds as soon as the ignition switch is turned on. Having the engine die if oil pressure fails is interesting but monitoring the gauges does the job also. "
 
"If you try to hook a relay to

"If you try to hook a relay to your oil pressure sending unit you will change the reading at the guage, I would have a fuel pump switch or hook it to a wire that comes on with the ignition."
 
"You need to hook it up to a r

"You need to hook it up to a relay that is activated by an oil pressure switch. This is a safety issue. You do not want the pump working if the engine is not running.

Have a great day,

Rob."
 
"Thanks rob, guess i just didn

"Thanks rob, guess i just didnt state it well enough, the new motors with efi it runs off the alternator, just thought with a carb, the oil pressure would be fine. dennis, why dont you like the electric in a boat?"
 
"if the fuel pump works on oil

"if the fuel pump works on oil presure,
does this mean there is no fuel being pumped until the oil presure builds up first.
this could be a problem if the fuel bowel is low,
or if the cranking speed does not build up any oil presure until the motor kicks in.

food for thought
rainer"
 
"actually, the switch turns on

"actually, the switch turns on at 5psi, its also adjustable if you want it higher or lower. converting these over I havent ever had a problem. I guess dave thought i ment t into the wire, not the oil passage. and as i stated, doing it this way is spark protected also."
 
"Ihave an electric pump with a

"Ihave an electric pump with a manual fuel pressure regulator. It is wired to the dash by a toggle. Works wondermous......
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115690.jpg
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