Extracting gasoline from tank - need schematics

[AceSpades]

Does anyone have electrical schematics on the fuel pump section for a 2004 V8. I want to extract gasoline from the tank by tapping off a line at the fuel rail. I will use a switch to manually trigger the fuel pump relay. The purpose is to refill jetskis when camping and far from a gas station. I do this on all my previous SUVs, but now i have a 4Runner and would like to do the same

 

[importman]

Does anyone have electrical schematics on the fuel pump section for a 2004 V8. I want to extract gasoline from the tank by tapping off a line at the fuel rail. I will use a switch to manually trigger the fuel pump relay. The purpose is to refill jetskis when camping and far from a gas station. I do this on all my previous SUVs, but now i have a 4Runner and would like to do the same

I can't seem to find a way to link a diagram of the fuel pump relay but from the one I saw it looks like the simplest way to do what you're trying to do would be to run a fused, switched wire from battery positive to terminal #5 of the relay. The diagram I saw was for my V6 model but I'm assuming it's the same for the V8. This is how the terminals are laid out on mine. When you see yours if it's laid out differently this obviously wont work.

__ < = Terminal #3

__ < = Terminal # 5

l l l
^ ^ ^
2 4 1
If you apply B+ power to pin 5 the fuel pump will run. If the key is turned off there should not be anywhere else the power can go. If I was doing it I think I'd use a spring loaded momentary switch so it runs when you press it and stops when you release it. And I'd definitely put an inline fuse in the power wire. There are other ways to wire it but to me this seems like the simplest.

After posting I notice my drawing doesn't line up perfectly but hopefully you can interpret it.

 

[AceSpades]

Im not seeing it with that drawing. What im looking for is the pinouts for the relay, and the wire color codes. Also where the fuel pump relay is physically mounted in the car

 

[Inv4drZm]

Is it better to siphon it somewhere on the return line underneath the vehicle, right in front of the fuel tank there are a couple lines easy to access.

This way, I'm assuming you can just start the engine to siphon and not have to trigger the pump separately.

 

[firebirdguy]

if you have a line to tap off from the fuel rail... why not just turn the key to engage the pump without starting the engine?

 

[Ed_C]

The relay is in the main fusebox under the hood, but it appears you just have to energize the C/OPN and EFI relays (also in the fusebox) since the fuel pump relay just connects/disconnects a inline resistor to slow the pump down.

if you have a line to tap off from the fuel rail... why not just turn the key to engage the pump without starting the engine?

The pump only stays on for a few seconds in the key-on position, I suppose if he doesn't mind cycling the key several times.

 

[importman]

if you have a line to tap off from the fuel rail... why not just turn the key to engage the pump without starting the engine?

The fuel pump only runs for about 3-5 seconds when you turn the key on. You’d have to keep cycling it.

 

[firebirdguy]

The pump only stays on for a few seconds in the key-on position, I suppose if he doesn't mind cycling the key several times.

The fuel pump only runs for about 3-5 seconds when you turn the key on. You’d have to keep cycling it.

yes the pump only stays on for a few seconds, but that is because it shuts off when it builds the correct amount of pressure... when you have an open fuel line that wont let it reach that pressure, it should stay on since the open fuel line wont allow it to reach the designated pressure. worth trying it to find out.

 

[Ed_C]

yes the pump only stays on for a few seconds, but that is because it shuts off when it builds the correct amount of pressure... when you have an open fuel line that wont let it reach that pressure, it should stay on since the open fuel line wont allow it to reach the designated pressure. worth trying it to find out.

The ECU doesn't look for fuel pressure since there's no fuel pressure sensor, so it will still shut the pump off after a few seconds. If the ECU sees a starter signal and engine RPMs (there's obviously more parameters than that but I'm trying to keep it simple) then it will keep the fuel pump running

 

[importman]

The ECU doesn't look for fuel pressure since there's no fuel pressure sensor, so it will still shut the pump off after a few seconds. If the ECU sees a starter signal and engine RPMs (there's obviously more parameters than that but I'm trying to keep it simple) then it will keep the fuel pump running

Correct. It doesn’t shut the pump off based on fuel pressure. In fact it only comes on in the on position to begin building pressure before you start the engine. It will also shut the pump off anytime it determines the engine has stalled as a safety function.

 

[jbtvt]

Im not seeing it with that drawing. What im looking for is the pinouts for the relay, and the wire color codes. Also where the fuel pump relay is physically mounted in the car

Relay is in the box under the hood. If you look at it I'm sure you'll see what he means. Color won't be any help unless you want to get into disassembling the box which is a PITA. But here's the diagram

 

[importman]

Relay is in the box under the hood. If you look at it I'm sure you'll see what he means. Color won't be any help unless you want to get into disassembling the box which is a PITA. But here's the diagram

You are so right. For me my crude drawing would do more for me than a diagram or wire colors.

 

[firebirdguy]

The ECU doesn't look for fuel pressure since there's no fuel pressure sensor, so it will still shut the pump off after a few seconds. If the ECU sees a starter signal and engine RPMs (there's obviously more parameters than that but I'm trying to keep it simple) then it will keep the fuel pump running

thanks for the info, i know on some other elect pump vehicles it seems to be pressure related, i had to check the psi on a older jeep cherokee & when the shrader purge valve was open the pump stayed running for a lot longer than the 3-5 seconds at start up.

also on that vehicle & my 4runner, if it sits for a long time, like a week or more, the pump stays on for noticeably longer than if it just sits over night, figured that was pressure related. but using the key was just a suggestion.

 

[AceSpades]

Thanks for the schematics! One thing to note though, Im seeing an Aux Air Injection controller which is telling me it is for a 2005+ 4runner and i have a 2004, so i hope the fuel pump circuit is the same. Ok what im seeing on the diagram is that the fuel pump relay is only used to trigger between 2 speeds (or low/high fuel pressure?) either direct or through a resistor as mentioned by Ed C... I have not seen this method used before with my previous SUVs, and i always prefer that my switch trigger the relay coil side instead of the high current contact side, but it looks like i have no choice but to work on the high current side, so i guess i will just use a DPST switch directly on the fuel pump to keep it simple.

Regarding the fuel tap, when i mentioned fuel rail i did mean the fuel return side of the fuel rail. I prefer to work at the fuel rail so im on top instead of having to get under the car to access the fuel tank because sometimes it is dirt roads at some campgrounds.

 

[jbtvt]

By 4th gen Toyota was pretty consistent with wiring schematics over the years, should be the same. You could wire a pair of DPDT switch to either side of the coil to manually switch pos and ground (ECU side is ground), or you could just tap into either terminal 4 or 5 with pos and let circuit function as normal (minus the upstream circuit-opening interlock) as suggested by Importman. I'd do that, any arcing would only affect the contacts for your bypass so normal operation wouldn't be affected. Worst case you wouldn't be able to draw gas without disassembling the switch and cleaning contacts. Or you could wire in a cap and resistor but that'd prob be overkill

 

[AceSpades]

a DPST switch on the B-R wire at the fuel pump will do it. Triggered on one side will run through the normal circuit, triggered the other way will run through my own supplied positive. My only question now is, where is the inline resistor physically mounted, is it also in the same engine electrical box?

 

[Ed_C]

a DPST switch on the B-R wire at the fuel pump will do it. Triggered on one side will run through the normal circuit, triggered the other way will run through my own supplied positive. My only question now is, where is the inline resistor physically mounted, is it also in the same engine electrical box?

"F8" in the illustration

 

[AceSpades]

Oh man, a big thanks to all you guys! I will be doing this in the coming days :thanks: