I am currently running the ECS fuel system on my 04. I would like to set it up so that the ECS supplied pump only runs under boost (pump is loud for normal driving).

My question is has anyone tried to use the 04 pump in a return style fuel system? I’m not sure it can supply enough fuel flow during non-boost operation if a portion of the flow is bled off back to the tank.

 

I am setup this way with the ECS fuel system. It will work fine.

You have to keep in mind that even your factory fuel system is returning fuel to the tank. On early models, it returned fuel to the tank from the rails. On later models, it returned fuel to the tank from the fuel filter, outside of the gas tank. On your model (and mine) the return is actually inside the tank. Without a return, your fuel system would overpressurize at idle, because there's not as much fuel leaving the rails as there is going into it.

You just don't want to set your new regulator so low that fuel pressure is lower than stock. In that case your factory fuel pump won't deliver the necessary fuel to your injectors.

 

That makes sense. I guess I just need to try it... Thanks for your input here and in my other tread.

Do you have any more info on the pump activation switch you used? Doug at ECS recommended the Hobbs switch.

 

No problem. A Hobbs switch will work great, but IMHO works better for centrifugal setups than other setups. On my TT setup I am actually activating the auxillary fuel pump through a nitrous WOT switch under the pedal. I didn't want to go with a Hobbs switch alone because by the time I build 1-2psi of boost, I could be 1 second away from 8-9psi of boost. Once those turbos get going, they really want to push some air.

The WOT switch allows the aux fuel pump to come on moments before it's needed and to also burp any potential air in the lines. I used a check valve between the aux fuel pump and the rails to minimize drainback (and to prevent the factory fuel pump from pushing against the aux pump) but it's still a concern.

The other reason I did a nitrous switch under the pedal is so I could prime the fuel system before turning the key. I just depress the pedal as long as I need to (you can audibly hear when pressure is up) and then crank and go. On other fuel setups I've had, you lose enough pressure between cranks that you often have to turn the key (not all the way) and wait... and sometimes turn the key again, and wait until fuel pressure is up, then crank. I wanted a more elegant solution and I think priming by depressing the pedal before cranking achieves that.

The only thing I will add is that I fear that a pedal switch only solution could cause me to lose fuel pressure when letting up off the pedal. I don't know how quick the pump stops after losing voltage and how quick boost will dump once the pedal is lifted. If it becomes problematic I will probably run a pedal switch in addition to a Hobbs switch so that even if the pedal is lifted the fuel pump will continue to run as long as there's boost.

 

Thanks for the help. You are really saving me some time pondering ideas. I'm going to go with the Hobbs switch and check valve, and might add the WOT switch for fuel priming and a back up. I have had a few starts that were rough because of low few pressure.

I'm still concerned about the the delay between coming into boost and the pump adding to the fuel pressure....

 

I mounted a pressure gauge on the rails so I could keep an eye on fuel pressure prior to installing my in-cabin gauge. To test out pump response, I started the car, opened the hood, reached my arm down to the microswitch and kept an eye on pressure. Due to the way my regulators are setup, I get a few extra PSI of pressure when the auxillary pump is running... it would climb in pressure pretty much instantly when pressing the microswitch.

I need to gather more data when the car is moving, at various fuel levels, and with increased fuel demands -- but so far it looks like my solution is working out great for me.

I understand that Andy @ A&A is also now running the ECS fuel kit on some cars with a Hobbs switch.

Oh, note that I installed my plumbing differently than the instructions tell you to. You can see I preserved my factory fuel line and used an adapter to take that out straight to the rails, and ran a second line for the aux pump with the check valve in line (it's hiding in the driver fender).

Quick pic of the microswitch: