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Electric fuel pump power supply

70beep82

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1967 GTX 440 auto without A/C. Recent acquisition that appears to be in stock configuration except the previous owner installed an electric fuel pump (no markings so brand is unknown) back near the tank. The power wire runs all the way to firewall along the fuel line. Has an in line 15 amp fuse and connects to the field terminal (single dark green wire) on the voltage regulator. Electric pump stopped working but the engine will run on mechanical pump just vapor locks when very hot outside.
Troubleshooting the electric pump today. Removed electric pump and applied 12v with hose in bucket of water. Steady output stream of water.
1) Is this a good place to get power for the electric pump? It is only on when the key is in run position but I haven’t seen this before. Measured 3-4 volts with key on and engine off. Have charged the battery within the last 6 days.
2) Could this be an attempt to provide lower voltage and therefore lower fuel pressure?
Thanks in advance!

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Last edited:
Fuel pump should be ran through a relay then to a 12v key on power source at the fuse box. To the alternator wouldn't be recommended.
 
If this is still a carburetted engine, I would get a Carter 4594 elec pump. They last forever....Keep the old pump for your toy collection.....
Run the pump direct to the carb, NOT through the mech pump.
Connecting it:
Use a relay as Aron said. Use the Bosch 30 amp 4 pin relay, very common. Connect pin # 85 to ground; connect pin #86 to the +ve side of the ign coil.
Two relay pins remaining. Connect one to the pump. The last pin on the relay should be connected to either the large stud on the alt or the batt +ve terminal, which ever is more convenient. Place a 10 amp inline fuse in this wire.

As a safety measure, you can install a three terminal oil pressure sw in the pump line. If the engine stalled in the event of an accident, the pump is switched off. The switch goes in the line where the oil pressure gauge/idiot light sensor is. Both Holley & Carter make these switches. Both perform the same function, I have found the Carter is usually cheaper.
 
Thank you. Detailed answers within one hour. This site is the best!
 
Not sure if this is still the case, but if you race the car NHRA also wanted a kill switch near the back bumper in case of a wreck. In any case you want to have the relay wired to an ignition accessory on the fuse block.

Mark
 
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