have a surge tank coming with a walbro 450 and instead of a hardwire that causes the fuel to heat up and reduced pump life, i was thinking of using the factory 8v/12v switching.

so instead of a relay hardwire, some power mosfets ramping up the walbro 450 voltage.

im working on something now in a simulation program, but have very basic knowledge.
im sure someone in the industry this is childs play.

 

FINE! Im going to make my own arduino powered fuel pump controller, and its gonna have blackjack and hookers!

 

In my experience, keep it as basic as possible. Less complexity is less chance for failure.

 

hi. i'm trying to understand what you wish to attain.
if you wish to not wire the walbro direct and run it full blast all of the time I can get that.
i'll have to dig my schematic out to see what is going on in the stock fuel pump wiring and relay switching.

I love my Arduino but it may be overkill.

if I'm correct in what I see. the pump is normally powered through a dropping resistor, that resistor's value calculated to drop battery voltage from ~12 volts down to ~9 volts dc. revert to ohms law using the pump resistance, supply voltage, intended voltage drop, etc...

ok. then when the ecu commands higher fuel pump pressure, the fuel pump relay (A27X) coil is sent voltage to close the contact in it. and full battery voltage is sent to the pump by bypassing the dropping resistor.

anyone who has ever popped the cover off of the relay can see how small the contacts are. I don't care if you use a black, green, red, plaid Omron relay. the contacts are tiny in comparison to how much current they have to pass. and correct design would place a capacitor across contacts that would have a potential to spark.

I've used solid state relays (SSR's) for years in industrial equipment. for this application one would be the hot ticket. trigger the pump when it needs full voltage and pass pump current through it (ssr) instead of through the Omron contacts. it would last forever.

search for an ssr with 3-32 volts dc input, and dc not ac output (aka: contacts) with a rating greater than the pump current. you'll be golden. and save the Arduino for steering your solar panels!

 

projects already done. its so i can hardwire the walbro but PWM it so it doesnt run full blast. input is based on the 9v/12v from the evo.

only issue i have is it may be loud from using the arduinos stock 500hz pulse witdh. testing with a 12v radiator fan was not quiet

actual install is on hold until i decide if i want to install the surge tank, or be lazy and just shove it in tank.

parts cost were cheap.
arduino $1.60 digispark or $12 metro mini
x2 logic power mosfets $3.20
and a few random resistors for the drop down voltage to 5v logic