Fuel pump question

[VSEXEC]

Hi all,
Another question about wiring my track car, vs v6. I want to put the fuel pumps on a switch, and i want to retain the fuel pump only allowing to start after sufficient oil pressure is achieved as is my understanding from the diagram. Am i correct in saying that the fuel pump shuts off if oil pressure drops while running? Can I just take the red/black wire that goes from the fuse box to efi relay and run the toggle switch in serie with this? So it will be cut the red/black wire and run to first pin on switch and then the other side of the cut red/black to the second pin on the switch. Sorry if this sounds confusing. Thanks

[Dazza92VP]

No the oil pressure switch connected into the fuel pump circuit is for if the fuel pump relay fails the car won't jyst shut down and die out in the middle of nowhere but it will not allow the fuel pump to turn on if there is no oil pressure

[krusty]

Simple way would to not run a check valve post fuel pump. Most engines achieve oil pressure after a couple hundred rpm if they're healthy.

Less complications on a track car the better I'd imagine

[vlad01]

or even better! have oil before the engine even cranks.

http://www.accusump.com/accusump_units.html

[VSEXEC]

So the best way to do it would be to use the violet wire that goes to the fuel pump then?

[VL400]

If you do that the switch needs to be capable of switching the fuel pump current (which may be significant if they are larger aftermarket pumps). But will mean you can crank until oil pressure comes up and it will not start.

You can switch the relay control wire (pin a6, green/white) with a lower current rated switch. Then it will crank until oil pressure and then start due to bypassing the fuel pump relay, can then flick the switch back to on so the fuel pump relay takes over.

[VSEXEC]

Would a 20amp 12v toggle switch be capable or do i need a higher amperage switch? Will be running duel bosch 044 fuel pumps.

[VL400]

Googled "bosch 044 current draw" and first hit .. http://www.bosch.com.au/car_parts/en/do ... lpumps.pdf

Max draw of one pump is 15.5A - little higher than running current but can safely say it wont exceed that for each pump.

What are you actually wanting to do with the switch? Just disable the pump so you can crank until there is oil pressure? Or something else, like manual fuel pump control?

[VSEXEC]

I just want it for manual pump control. I have ignition and accessories on toggles and want fuel pump on a switch as well

[Charlescrown]

I question why you want to crank the engine to get oil pressure before you start the engine. Modern oils have fantastic boundary layers to protect the parts under such conditions and slow rotating speeds is the worst condition for engine wear. I know from past experience in the 70's with race cars we did crank the engine to get oil pressure before starting but was it really necessary? Pull any modern engine apart and have a look at the bearings they will be as good as the day they were put in.