Electric fuel pump from coil?

[dmopar74]

Can I run the switched source for my fuel pump relay off the coil +, or does the ballast resistor not allow that?

 

[toolmanmike]

Can I run the switched source for my fuel pump relay off the coil +, or does the ballast resistor not allow that?

I would use the positive side of the ballast or run a wire over to the starter relay.

 

[Dana67Dart]

You can take the feed from before the ballast.

IMHO

You should use a relay tied to batt pos and then power the trigger from a switched source.

Keep in mind the switched source needs to be live while cranking AND in run but not in any other key position.


You might also want to look into an inertia switch like newer FI cars have. So the fuel pump will be de-energized in the event of a crash.

You don't want the fuel to keep pumping if you end up with a severed fuel line.

 

[Bewy]

Safety sw described above is a good idea, I have one on my car.
No problem using the coil + , but connect to the incoming side of the bal res, not the side that connects to the coil. Typical small Bosch relay only draws about 1/6 amp.

 

[Dana67Dart]

Typical small Bosch relay only draws about 1/6 amp

Just for clarification.

The reason I suggested using a relay is to shift the current draw of the fuel pump off of the ignition switch and put it directly to the battery or alternator output.

The relay itself has a negligible draw.

 

[dmopar74]

I am using a relay as stated in op, but good looking out.

 

[Dana67Dart]

I am using a relay as stated in op,

I missed that.

 

[72RoadRunnerGTX]

Never add loads directly to the battery if still running an ammeter, all loads need to be on the alternator side of the ammeter as are all other factory loads. Using an oil pressure switch will cover pump operation while cranking and kill the pump with an engine stall.

Why load placement matters when running an ammeter,