I have wired a halo LED switch to the fuel pump. This serves 2 purposes:
1. A simple anti theft device
2. Drain carbs of fuel before lay up when engine is running and switch is off.
Now here's the unexpected thing.
The LED is connected between power and ground to the fuel pump, after the switch, so should light up when switch is on.
When ignition is on, (carbs drained from last year) pump ran for a couple of seconds, then stopped and the LED went off. Turn ignition off, then on and the sequence repeats.
So now LED is off.(pump not running)
Push starter, engines fires up and LED is on, obviously the pump is running to top up the carbs.
OK, so what I think is happening is the ignition unit turns off fuel pump when engine is not running - I believe this correct operation and is a safety feature.
The LED being turned off when pump stops due to carbs being full is because the ground is switched by the pump so there is no electrical path to complete the earth circuit.
(Thinking about it now, I'm wondering if I should have wired the LED ground prior to the switch)
A piss poor photo in the dark, the switch fits inside one of the holes in the alloy knee protectors.
1. A simple anti theft device
2. Drain carbs of fuel before lay up when engine is running and switch is off.
Now here's the unexpected thing.
The LED is connected between power and ground to the fuel pump, after the switch, so should light up when switch is on.
When ignition is on, (carbs drained from last year) pump ran for a couple of seconds, then stopped and the LED went off. Turn ignition off, then on and the sequence repeats.
So now LED is off.(pump not running)
Push starter, engines fires up and LED is on, obviously the pump is running to top up the carbs.
OK, so what I think is happening is the ignition unit turns off fuel pump when engine is not running - I believe this correct operation and is a safety feature.
The LED being turned off when pump stops due to carbs being full is because the ground is switched by the pump so there is no electrical path to complete the earth circuit.
(Thinking about it now, I'm wondering if I should have wired the LED ground prior to the switch)
A piss poor photo in the dark, the switch fits inside one of the holes in the alloy knee protectors.