flathead31coupe
Well-Known Member
can i trigger a relay for my fuel pump off of the starter relay on my dart? is there a good diagram for wiring up a pump using a three wire oil pressure switch.
electric fuel pump wiring?
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Yup. Just come off the BIG positive terminal. You'll still need an ign on for the trigger, though. But use the big terminal for + power in.
flathead31coupe
Well-Known Member
can that ign on be the ign wire from the starter relay going to the ballast?
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67Dart273
Well-Known Member
All you need is google and about 10 seconds
The one marked NO from the ignition switch is your (normally) dark blue IGN1 "ignition run" and the one marked NC comes from your yellow start wire on the starter relay
The "C" (common) DOES NOT GO to the pump but rather to the pump relay coil
The one marked NO from the ignition switch is your (normally) dark blue IGN1 "ignition run" and the one marked NC comes from your yellow start wire on the starter relay
The "C" (common) DOES NOT GO to the pump but rather to the pump relay coil
flathead31coupe
Well-Known Member
yellow start wire? i think i have it right. but no go... if the oil pressure is preasent it will make the switch and send 12v to the c in witch will trigger the relay for the pump correct?
flathead31coupe
Well-Known Member
so the no on the oil pressure switch connects with the dark blue 12v wire at one end of the ballast? and the nc wire goes? is that the wire on the starter relay that goes to the starter sol ? i may need a temp button or switch to get fuel to the carb to start it.
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flathead31coupe
Well-Known Member
anyone done this with the oil safety switch? any pics of wire connections? or a complete drawn diagram.
flathead31coupe
Well-Known Member
so looking at these pics is the above diagram wrong
flathead31coupe
Well-Known Member
when i wire it up as shown in the bottom pic the car cranks as soon as i turn the key on....i dont know why i cant get this lol shouldnt be hard. seems i cant get the two wires on the oil switch right. the hot in run wire, and the hot in crank wire. i thought the hot in run wire was the + wire for the coil off the ballast.and the hot in crank wire was the sol to the starter..
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flathead31coupe
Well-Known Member
Three terminals, C,N,NO
C goes to fuel pump
N goes to starter solenoid
NO goes to ignition "on" terminal
So, fuel pump gets power during cranking and also when key is on AND oil pressure is over 5 p.s.i. this is what i thought should work,,, as stated in #4 post is this correct?
C goes to fuel pump
N goes to starter solenoid
NO goes to ignition "on" terminal
So, fuel pump gets power during cranking and also when key is on AND oil pressure is over 5 p.s.i. this is what i thought should work,,, as stated in #4 post is this correct?
flathead31coupe
Well-Known Member
i have it wired as in post#4 when i turn the key to crank it cranks but when i let up on the key to run it stays cranking...help lol and thanks
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67Dart273
Well-Known Member
I don't know. Your description of C/ NO/ NC should work. The only difference is that you feed C to fire a relay instead of direct to pump. Not trying to talk down to you. C is like the center of a so called "2 way" 3 terminal switch. Whichever way the switch is thrown, one of the outer terminals connects to center which is "C" or "common."
So NO normally open, when there's no oil pressure, that contact goes nowhere
NC when there is no pressure that contact goes to C
So when the start relay fires, that should send power via NC and C off to the pump or pump relay
When the oil pressure comes up, the pressure switch flips, connecting NO to C. Now the power from NO feeds through C and powers the pump or relay, and the NC is now open (with pressure) and it goes nowhere
So NO normally open, when there's no oil pressure, that contact goes nowhere
NC when there is no pressure that contact goes to C
So when the start relay fires, that should send power via NC and C off to the pump or pump relay
When the oil pressure comes up, the pressure switch flips, connecting NO to C. Now the power from NO feeds through C and powers the pump or relay, and the NC is now open (with pressure) and it goes nowhere
67Dart273
Well-Known Member
Only advice I can give you is either disconnect the pressure switch and test it on the car, or pull it off and test with air pressure. Use a test lamp or meter and confirm that it is working as expected. NC to C should be closed with no pressure, and NO to C should be closed with pressure
flathead31coupe
Well-Known Member
thanks for the reply, the no on the pressure switch goes to the dark blue wire that is hot when the key is on its the 12v on one side of the ballast correct? and the nc goes to the starter sol on the starter relay.
67Dart273
Well-Known Member
Yup. When the pressure flips the switch, the NO connects to the C and then the key ignition circuit should keep the pump/ relay powered. I have no ideas on what you did with the "run" problem. Does the problem still exist if you unhook the pump wiring/ relay and just jumper the pump manually?
The run-on may not have anything to do with pump wiring..................
The run-on may not have anything to do with pump wiring..................
pishta
I know I'm right....
I'd run it off its own panel switch to a relay that is hot off the fuse panels ACC position. Reasoning is that it can be turned on/shut down manually and even makes a theft deterrent if its not labeled. Running it through an oil pressure switch is nice, but youll want the carb full of fuel before you even try starting the car, not cranking it waiting for it to build oil pressure. That's just me who owned one wired up like this. Made sense to me.
flathead31coupe
Well-Known Member
for what what ever reason the bottom pic in post #9 is the way it had to be wired to work, thanks for the help....
flathead31coupe
Well-Known Member
yes thanks again
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