Fuel Pumps?

According to the schematics I’m looking at for the engine controls our V6 3rd Gens have two fuel pumps. I was aware of the pump within the gas tank, but where is this other fuel pump and what is its purpose?. For those with the schematics it is pins 4 & 5 on connector E10. E10 is a 35 pin connector I presume in the engine bay?

Oh, why does this vehicle have a Fuel Pump Control ECU for the pump in the tank?

 

Low pressure pump (in tank) feeds the port injectors and the high pressure pump.

High pressure pump is bolted to engine and feeds the direct injectors. It uses a cam lobe to pressurize, not unlike carb fuel pumps from back in the day.

Most modern vehicles have fuel pump ecu's now to control speed and pressure dependent on conditions.

 

Thanks. If it is much like the mechanically operated pumps of my youth, why is there an electrical connection? Just trying to learn. Where is the pump bolted to the engine? I’d like a peak at it.

 

I actually don't 100% know but it looks like its there to detect a failure and tell the flow valve to prevent fuel from entering the pump during a major failure.

 

@Toycoma2021 You got me interested in how it works. It appears the electrical connection controls the fuel flow from the low pressure pump in the tank.

I found this video interesting.

 

Good find. Seems like some of the comments go into more possibly accurate detail. Got some studying to do.

 

The high pressure direct injection pump is mechanical, but it is controlled by the ECU. In particular, it is only on in certain contexts (rpm, throttle position, etc). The 2gr-fks uses both port injection and direct injection, but not (ever?) necessarily at the same time.

Direct fuel injection injects fuel directly into the combustion camber during the compression stroke when pressure is high inside, therefore the fuel needs to be at a high pressure (~10 atmospheres rough estimate).

Direct injection tends to produce more power but also cause carbon build up on the intake valves. Port injection tends to produce less power but not cause the same carbon build up. There might be other reasons toyota used both.

More info here:

https://en.wikipedia.org/wiki/Toyota_GR_engine

https://en.wikipedia.org/wiki/Gasoline_direct_injection

 

Both used at the same time -Either Mode.
ECU adjusts the injection time and the volume for Port and Direct injectors in Either mode.
Direct injectors spray at 290° in Either mode and 320° in Direct mode

 

DI has the ability to precisely time and inject the exact amount of fuel needed for any given condition, where as a port system is really at the mercy of valve timing.
So now you put variable valve timing along with DI and port (which is basically infinitely variable injection) and that's where the power gain and emission benefit come from. I'm not a fan of DI but Toyota did a good job with the D4S, otherwise I would not have bought the truck.