BYPASS fuel pump relay - 2008 Stang

[08Shelby1]

I want to override (bypass) the relay and run the dual fuel pumps to drain the fuel from the tank. I found the RELAY under the hood (#21) for the fuel pumps. Now I need to trick the ignition fail safe and pump the fuel from the disconnected fuel rail line. How?

 

[07 Boss]

Can't you just unhook the fuel line like at the filter and turn the ignition on? Since the pressure will not be getting to the fuel rail sensor, the pumps should continue to run, no?

 

[drive_55_not]

Can't you just unhook the fuel line like at the filter and turn the ignition on? Since the pressure will not be getting to the fuel rail sensor, the pumps should continue to run, no?

With the key on the pump will run for a few seconds then turn off ..

When I drain my tank to switch over to race gas I run the tank down to less than 1/4, then disconnect the line at the filter, attach a section of fuel line to a gas can, then crank the car for 15 seconds or so, let the starter rest and crank again til the tank is dry ..

Takes less than 5 minutes to pump the gas out that wayy ...


.

 

[Wes06]

I asked lito for a tune that will leave the pump running with ignition to on.

Instead of a 5second prime it'll just run and run

 

[07 Boss]

With the key on the pump will run for a few seconds then turn off ..

When I drain my tank to switch over to race gas I run the tank down to less than 1/4, then disconnect the line at the filter, attach a section of fuel line to a gas can, then crank the car for 15 seconds or so, let the starter rest and crank again til the tank is dry ..

Takes less than 5 minutes to pump the gas out that wayy ...


.

Oh. I just figured it would keep running until the rail pressure got up to 39 psi or whatever it is set at. So it only primes for a few seconds and then shuts off regardless of rail pressure? I've never drained the tank but I have a fluid transfer pump that I would use anyways.

 

[TexasBlownV8]

It'll cut off after a couple of seconds even with line disconnected and unable to build up pressure.
I drained my tank (well, no more than 1/4 full) by turning key on and off while fuel drained a few seconds at a time, into a gas can, with line unhooked at the fuel filter. Yuk.

 

[08Shelby1]

Good idea's everyone... this car is smarter than Albert Einstein...

Car has "full" tank of gas... going on two years of age. Really like to drain it.

--- I own a "fancy" 12V DC extraction pump; can't push the plastic hose past the "turn over safety ball" within the fuel inlet.

--- With fuel line disconnected at the rail, pump cuts out seconds after ignition is powered up.

They sell a set of "switches" that plug in to the fuse position, taking place of the "relay"... Simple ON/OFF deal... $50 chance?

I could lift the car and try the filter disconnect at fuel line... Trying to keep it simple.

ANY OTHER THOUGHTS?

 

[Wes06]

Who's your tuner?

Like I said lito made me a tune so that instead of shutting off it just keeps going
Will probably empty the tank in no time

 

[Timmbo]

Good idea's everyone... this car is smarter than Albert Einstein...

Car has "full" tank of gas... going on two years of age. Really like to drain it.

--- I own a "fancy" 12V DC extraction pump; can't push the plastic hose past the "turn over safety ball" within the fuel inlet.

--- With fuel line disconnected at the rail, pump cuts out seconds after ignition is powered up.

They sell a set of "switches" that plug in to the fuse position, taking place of the "relay"... Simple ON/OFF deal... $50 chance?

I could lift the car and try the filter disconnect at fuel line... Trying to keep it simple.

ANY OTHER THOUGHTS?

Heres a vid on how I emptied my tank for my new return system install:

 

[Mach2burnout]

Heres a vid on how I emptied my tank for my new return system install:

So you just connected a battery straight to your in tank pump ?


Sent from iPhone

 

[07 Boss]

So you just connected a battery straight to your in tank pump ?


Sent from iPhone

Simplest way is usually the best way.

 

[08Shelby1]

Nice VIDEO and thanks to everyone who answered.

So I'll disconnect the electrical connector from one of the fuel pumps located in the trunk, then figure out which wires are +12V and neutral. Then I'll wire a battery to one... see if it will pump fuel. This way I bypass the ignition and steer clear of any "error" codes.

Already blew a 5 and 15 AMP fuse "probing" hot... Shouldn't do that!

 

[Timmbo]

Nice VIDEO and thanks to everyone who answered.

So I'll disconnect the electrical connector from one of the fuel pumps located in the trunk, then figure out which wires are +12V and neutral. Then I'll wire a battery to one... see if it will pump fuel. This way I bypass the ignition and steer clear of any "error" codes.

Already blew a 5 and 15 AMP fuse "probing" hot... Shouldn't do that!

Your power connection is the driver side pump hat. Passenger side is just a sending unit. 12 V pump power is the pink wire w/black stripe. Ground is black.

 

[08Shelby1]

Gonna give it a try Sunday...thanks again