[Diy_efi] Re: Looking for circuit to turn transfer pump off at certain

[Toyota Supra]

hey bevan, thanks for the reply, maybe this will help clarify ...


here are the specifics, my gas tank is a saddle tank, meaning that it has 
two sides to it like saddle bags on a horse. now the pumps are on the left 
side, and the mechanical venturi valve that used to transfer the fuel from 
the right side, had to be removed.

so my dilema is, how do i get fuel from the right side of the tank, to the 
left side where the fuel pumps sit, so that i am not driving around on only 
a 1/2 tank of usable gas, even though the entire tank is full?

well, my design thought was to have a transfer pump intank, that drew from 
the right side, to the left side, at all times that the car was on, except 
for when the right side of the tank got low on fuel. this is because the 
fuel acts as a lubricant to the transfer pump, and if it ran dry for any 
period, it would probably burn up.

so the way i decided to control the transfer pump was to use the existing 
sending unit that is in the right side of the tank (which reads 0 to 3.5v, 
full being 0v - bone dry being 3.5V) and use that sending units output as a 
reference signal for the circuit, and having that circuit turn a relay off 
(or on) to control the power to the transfer pump.

i appologize if this reads confusing and that it is so long, but i wanted to 
be as detailed as possible. if you think your circuit design would work, i'd 
be very grateful if i could have a copy of it. thank you for the reply

-j








From: "Bevan Weiss" <kaizen__ at hotmail.com>
>Reply-To: diy_efi at diy-efi.org
>To: <diy_efi at diy-efi.org>
>Subject: Re: [Diy_efi] Re: Looking for circuit to turn transfer pump off at 
>certain voltages
>Date: Sat, 9 Nov 2002 12:30:52 +1300
>
>
>----- Original Message -----
From: "Steve Hutson" <customfab at websurf.net>
>To: <diy_efi at diy-efi.org>
>Sent: Friday, November 08, 2002 11:59 AM
>Subject: [Diy_efi] Re: Looking for circuit to turn transfer pump off at
>certain voltages
>
>
> > > Message: 3
> > > From: "Toyota Supra" <turbosupramk3 at hotmail.com>
> > > To: diy_efi at diy-efi.org
> > > Date: Thu, 07 Nov 2002 12:50:40 -0500
> > > Subject: [Diy_efi] Looking for circuit to turn transfer pump off at
> > certain voltages
> > > Reply-To: diy_efi at diy-efi.org
> > >
> > > if anyone has this, please reply to me privately, i can't seem to find
> > > anything online, thank you very much
> > >
> > ---------------
> >
> > I'm not sure EXACTLY what you are referring to by xfer pump or 'certain'
> > voltage. I designed a simple circuit (you can build for~$20) that uses a
> > return signal from any 5v referenced sensor (IE TPS, CLT, IAT, 
>ect.)(0-5v
> > return) that can be infinitely adjusted (with hysteresis) and will 
>control
>a
> > relay for MANY uses. With slight mods, could be used at any voltage 
>level.
> > Any help?
>
>I'm not sure exactly what's required, but it sounds like a comparator with
>hysteresis...
>In which case a simple opamp, with some feedback applied would do the 
>trick.
>Assuming that it's a voltage level input, if it's current then you would
>need a current->voltage conversion (ie maybe as simple as a resistor or if
>required a more complex current->voltage converter).
>However this is assuming we're talking about a 0-5V signal, if we're 
>instead
>referring to a 0-50uV (or some other such) signal then ofcourse things are
>different...
>
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