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I'm looking at wiring up an electric fuel pump controller and it wants 12 VDC switched input, I have been poking around under the hood trying to find something but I haven't had any luck so far. I have a 77 F250 with a 351M with factory air.
0.1A seems awfully low to me. Does the specs. give max watts?
I only ask because before you use a key on 12V source you’re going to need to know the load and what the key on 12V circuit is already rated for (fuse and wire size) and what it already supplies.
Heres what a quick search showed me…. as I figured your still running a carburetor or only need low psi demand pump to replace a mechanical diaphragm pump.
0.1A seems awfully low to me. Does the specs. give max watts?
I only ask because before you use a key on 12V source you’re going to need to know the load and what the key on 12V circuit is already rated for.
Heres what a quick search showed me…. as I figured your still running a carburetor or only need low psi demand pump to replace a mechanical diaphragm pump.
Big Horn
I've already got it powered if you will, I just need the voltage sense I guess for the key being turned. That's why it's only 1/10 of an amp.
The voltage regulator has a key ON input wire (green?) that is used as a "Turn ON" signal to bring the alternator online after starting.
Do you need power during Start and Run, or just the Run position of the key?
If both you might need to also use the "I" connection on the starter solenoid.
Jim
Do you know why it needs a "tach input"?
Just curious
Also adding the option diode is a good idea, but something you can kick down the road if you don't have on hand.
Jim
Do you know why it needs a "tach input"?
Just curious
Also adding the option diode is a good idea, but something you can kick down the road if you don't have on hand.
Jim
I think it's so it knows the engine is still running. The idea is that if I get I to an accident or something like that and the engine quits the fuel pump shuts off so I don't explode.
You can also pick up the tach signal at the ignition module, might be easier to get to.
I didn't think about that spot for the tach, the instructions said to use the ignition coil to also find that. I was wondering if I couldn't find a voltage source on the ignition controller module. I was hoping someone could tell me that was a good spot to look for one.
I would use a test light and find a key on 12v sours and run that wire to an oil pressure fuel cut off switch like the one in the link.
Tee it in to the top of your oil filter housing where you current OP switch is.
The way the pump only runs when the engine is running.
I didn't think about that spot for the tach, the instructions said to use the ignition coil to also find that. I was wondering if I couldn't find a voltage source on the ignition controller module. I was hoping someone could tell me that was a good spot to look for one.
You are correct, the ignition module might be a better choice. Plus you can get both needed inputs at the same location.
12 volts would be the red wire on the module side of the 2 wire power plug. I believe this would have power in both Run and Start key positions.
The tach negative, most likely a green wire, runs to the 4 wire plug on the ingition module.
Jim
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