Quick run down on what you guys have done to setup fuel pump operation.
Simply run a relay in the coil +ve and decent guage wire going to fuel pump, or have you gone more in depth? Best place to mount on LJ? Was going to put it in the engine bay to mean less wire being run.
Eletric Fuel Pump.
Started by
_Chaotic_
, Jan 02 2007 08:45 PM
9 replies to this topic
#2
_Monkey_
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Posted 02 January 2007 - 09:04 PM
This is where mine is mounted,there's a small bracket welded to rail and pump mounted on that.
What fuel pump will you be running??
What fuel pump will you be running??
#3
TerrA LX
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Fulcrum Fixture
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Posted 02 January 2007 - 09:10 PM
its not a normal relay to the coil but a LPG type that sensors the motor is running or not rof safty sake.
#4
_devilsadvocate_
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Posted 02 January 2007 - 09:17 PM
You will need to have it wired so the pump will only work if the motor is turning/ running.
This is for safety, the most obvious reason being that if you are in an accident and the fuel line ruptures, the motor would obviously stop, but you would still have fuel being pumped through the rupture......you might not be able to turn off the ignition! I would hope that the absence of this feature would make the car unroadworthy in an inspection.
The best solution is a tachiometric relay which activates the pump for about a second or so when you turn the ign to on and will continue to provide it power once it senses a pulse coming from the coil.
Other alternatives are vac switches or the oil pressure switch. The oil pressure switch possibly would be unsatisfactory in that fuel pressure wouldnt be there until you had oil pressure when starting, but a toggle primer switch(momentary on) with cover/guard would overcome that or a wire that goes from the starter relay terminal. Vac switch will work within half sec of turning the motor.
Just seen post ^, there after I started.
This is for safety, the most obvious reason being that if you are in an accident and the fuel line ruptures, the motor would obviously stop, but you would still have fuel being pumped through the rupture......you might not be able to turn off the ignition! I would hope that the absence of this feature would make the car unroadworthy in an inspection.
The best solution is a tachiometric relay which activates the pump for about a second or so when you turn the ign to on and will continue to provide it power once it senses a pulse coming from the coil.
Other alternatives are vac switches or the oil pressure switch. The oil pressure switch possibly would be unsatisfactory in that fuel pressure wouldnt be there until you had oil pressure when starting, but a toggle primer switch(momentary on) with cover/guard would overcome that or a wire that goes from the starter relay terminal. Vac switch will work within half sec of turning the motor.
Just seen post ^, there after I started.
Edited by devilsadvocate, 02 January 2007 - 09:23 PM.
#5
_bodallafella_
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Posted 02 January 2007 - 11:08 PM
You just run standard a relay off the coil or ignition switch and run a big fused wire directly from the battery with an earth wire back to the battery.
If you want the safety feature the Holley oil pressure switch is fine. It cuts power to the pump if there is no oil pressure. The switch has 3 terminals and is wired so that the pump works during cranking.
http://www.holley.com/12-810.asp
You should not mount it in the engine bay as an electric pump won't suck that far. They normally need to be within a few feet of the tank and below most of the fuel.
If you want the safety feature the Holley oil pressure switch is fine. It cuts power to the pump if there is no oil pressure. The switch has 3 terminals and is wired so that the pump works during cranking.
http://www.holley.com/12-810.asp
You should not mount it in the engine bay as an electric pump won't suck that far. They normally need to be within a few feet of the tank and below most of the fuel.
Edited by bodallafella, 02 January 2007 - 11:11 PM.
#6
_devilsadvocate_
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Posted 02 January 2007 - 11:25 PM
Boddafella, the safety feature shouldnt be a matter of personal choice.
Yes there is the switch supplied by Holley which I forgot to mention, though it has its own hassles in having to be plumbed with the correct fittings to the oil system and possibly is expensive.
If you have an existing oil pressure switch its electrical action can be used to trigger a relay etc.
Yes there is the switch supplied by Holley which I forgot to mention, though it has its own hassles in having to be plumbed with the correct fittings to the oil system and possibly is expensive.
If you have an existing oil pressure switch its electrical action can be used to trigger a relay etc.
#7
TerrA LX
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Posted 02 January 2007 - 11:28 PM
^ also dont put the pump in the bay as heat will affect its operation.
#8
_bodallafella_
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Posted 02 January 2007 - 11:51 PM
The Holley switch is not expensive, it's about $25.00 and it is optional. There is no legal requirement for a safety switch and many cars with factory fitted electric fuel pumps don't have one.
It's not that I am against safety features but it's only protection from a pretty unlikely scenario.
And you spelled my name wrong Devilsavocado.
It's not that I am against safety features but it's only protection from a pretty unlikely scenario.
And you spelled my name wrong Devilsavocado.
#9
_Monkey_
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Posted 02 January 2007 - 11:59 PM
hahahahaha.Devilsavocado.
sorry devil's, but you gotta admit thats funny.
#10
_devilsadvocate_
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Posted 03 January 2007 - 12:19 AM
Are you sure about that, perhaps cars supplied with electric pumps back in the 60's and 70's did not have the saftey feature, which would exclude them from having to have it today, but for any modified vehicle that originally was equipped with a mechanical pump Id be surprised if that was allowed.There is no legal requirement for a safety switch and many cars with factory fitted electric fuel pumps don't have one.
Certainly this feature is standard in any electric pumped vehicle produced in the last 20 years, whether manufacturers took it upon themselves to do this or its a design rule I dont know. This feature was overlooked in lpg vehicles until ~12 years ago, but is now, it took an "accident' for the legislation to occur.
Really, there are many scenarios where the lack of this feature could produce a problem. How much fuel do you think a pump could give out in 10 seconds, say if one of the fuel lines dropped off etc.
If not for your own safety, perhaps for the safety of those who may end up being involved in your accident.
The holley switch sounds reasonably priced, but that doesnt include all the adaptor bits that may be needed to plumb it to your oil lines?
Devilsavocado: forbidden fruit?
Edited by devilsadvocate, 03 January 2007 - 12:27 AM.
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