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View Full Version : LaserInjFuel Pump 12 volts at each wire?


coffeeguy
08-05-2023, 06:35 PM
Boat cut out and fired up then quit again, Though I may be out of fuel. Upon refilling nothing. Has spark but high pressure pump very low hum and no real pressure generated. (Vacuum low pressure pump is working ok.) When I tested the 2 wires (+&-) both showing over 12 volts. Is this normal or should the wire to negitive side of the pump just be a ground?
25two.stroke
08-05-2023, 07:15 PM
Positive wire has +12v all the time when the ecu connector is connected. Ground side of the pump is switched -12v that comes from the ecu. If you have +12v on the ground side then your ecu or wiring harness is shot.
PanRonnie
08-06-2023, 02:04 AM
12 volts at both terminals is normal with the engine not running
the black rectangle is the technicians guide
coffeeguy
08-06-2023, 05:19 AM
I had a vauge recolation that both could be positive, even though it made no sense to me.
25two.stroke
08-08-2023, 11:20 AM
12 volts at both terminals is normal with the engine not running
the black rectangle is the technicians guide

What! What! No, thats weird. I know I have seen that NOT occur. Good to know that it can be ok! I learned that today.
derekfl
08-08-2023, 07:21 PM
I guess since the ground side is the switch, it will read 12 volts between pulses. And unless at high throttle, more time is spent with injector off than on, and a digital meter refreshes WAY slower than an injector pulses on and off.
PanRonnie
08-08-2023, 11:38 PM
Pulse With Modulation is a common way to do voltage control now
You can use cheaper drivers and less problems with heat build up in the pcb board
https://us.aspina-group.com/en/learning-zone/columns/what-is/011/
OnPad
08-09-2023, 01:12 AM
Pulse With Modulation is a common way to do voltage control now
You can use cheaper drivers and less problems with heat build up in the pcb board
https://us.aspina-group.com/en/learning-zone/columns/what-is/011/

I seen that the other day, on a race car build. They had the fuel pump driven off the throttle signal. The more demand needed, the faster the pump ran. Way less amp draw = more hp.
coffeeguy
08-13-2023, 06:23 AM
Different pump and bought injection fuel pressure gauge (that didn't come with the "Ford" schrader valve connection so made one) and ffired right up
While go to the VST delete soon.