Closed loop fuel pump setup

[XKLABA 1]

Pavlo,

ok in to 7, do I need to change IGN to 1..7TTL ?

I have had custom switching unit made for this specific purpose that only goes one way, we decided a H bridge was not needed for this as the motor only needs to go one way and we could build a stronger more durable unit at the same size, I'll set it from 35% and scale up to 95%

I'm going to run a ignition source to the main pump relay and have cut in the switching unit between the relay and pump, I think the FuelPump 2 is already set at 0% duty so I can just leave it

the surge tank is 8.5 liters and the lift pump is the Walbro E85 pump so if it doesn't turn on till the motor is running it won't matter, I always manually fill the surge tank anyway so that also won't be an issue

even if they can change FP2 to run identically to FP1 settings with prime times and such would be good

Michael,

I thought of doing it that way but my idea is to have the lift pump "flush" the heated fuel returning from the motor out of the surge tank so having the lift pump slow down with the main pump reduces that

I have read your build thread, looks good mate, while reading it I saw you put something in for the TPS signal, any chance you can PM me what you did ?

Cheers,

Michael

[MikeyB571]

Michael,

I hadn't thought of it that way, my thinking was that with the pumps working on a pwm then they are not pushing so much fuel to the engine and so you won't be getting lots of heated fuel back to the swirl pot. This should reduce the fuel temperature, this was one of the main reason for me adding pwm control. That and the reduced noise from the pumps.

In fact I have decided to put three channels of H-Bridge, one for each pump (lift, and 2 044's) all driven by a single output from the ecu. Then there is no step function at all.

Michael.

[XKLABA 1]

Michael,

I have a Weldon 2025 as my main pump, massive over kill, and as we have found out the hard way, a very very loud pump so not only do I want to slow down the flow of fuel I need to significantly reduce the noise as this is a street car

since I have mounted the surge tank under the boot floor the pump can't be gravity feed which is the reason I went the Weldon

I wanted the lift pump flowing lots and able to pump E85, hence the Walbro, as much as the lift pump only has to out flow the injectors I wanted the main pump sucking as fresh and cool main tank fuel as possible, which is the main idea for the way I have set it up

so the lift pump will move alot of fuel through the surge tank and the main pump will only be flowing a little more then it needs to to feed the engine making it so less fuel is returning to the surge tank warming everything up which is also why I have such a big surge tank ( 8.5 liters ) to help absorb the heat from any fuel that does get into the surge tank returning from the engine

Michael

[XKLABA 1]

Ok so I have got my setup going and it works good so far

connected to IGN 7 on TTL set at 2khz ranging from 25% up to 90% duty but I still want to do more fine tuning on this setup

wondering what other people have got their settings set at ?

or any direction I should be going with my settings ?

Michael

[pavlo]

10khz should be better.

As for the duty it will depend on the pump(s), but I think you have the idea.

[XKLABA 1]

I have played with it some more and ended up at 4khz as any more the that and the min duty gets to low, >20%, to make any difference

while sitting there playing with the idle settings I heard the main pump start to gurgle so I shut it off and turned on the out put for FP 2 though out put testing to hear it turn on and fuel going in to the surge tank filling it back up, so it looks like the lift pump isn't running while at idle but not sure about while it's under load and I'm to worried to take it for a drive to see if it is working while driving

the duty for FP 2 is set at 0%

should I change it to an IGN signal to turn on the lift pump ?