Volks,
This series of questions involves for me a Diesel TDI engine, but the same
principals are involved with a fuel injected gasoline engine, so hence the
cross-posting.

We are going to be starting on a TDI conversion that I want to "kick up a
notch" as far as instrumentation goes.  The eight function gauge that I have
installed into our TriStar has the ability to use a few flow meter so that I
can view the instantaneous amount of fuel being consumed by the engine.  The
problem is I can't see how to connect the fuel meter so that I can get an
accurate reading.  The meter is basically a little "box" with a fuel input
and output on it and it will give an electronic "pulse" per every unit of
fuel that flows trough it.  The gauge attached to it counts the pulses and
determines fuel flow from the amount of pulses over time.  Now as we all
know, modern Diesel and Fuel Injected gasoline engines has an input from the
fuel tank and any fuel it doesn't use goes back to the tank.  As a result,
the line from the tank to the engine doesn't show the real fuel consumption
as there is always fuel going back to the tank.  A the to and from lines are
never a constant difference ratio, the only thing I can see doing is loop
the engine's fuel output into the input of the fuel pump instead of back
into the fuel tank.  The main reason why we dump fuel back into the tank is
it makes the system self bleeding system by removing air bubbles.  Air
bubbles are bad for fuel pumps.  The other reason for fuel being returned to
the tank, especially in a Diesel is it cools the fuel off as the TDI will
give less power if the fuel is too hot - hence the fuel coolers on the pump
d�se engines.  So basically I am wondering if there is any such thing as a
"bubble trap" out there to prevent air bubbles from being trapped in the
system and if there is a way that I am missing about installing fuel
metering devices?

For a picture of our prototype engine monitoring gauge see:

http://www.fastforward.ca/gallery/1005instrumentpod.jpg

Cheers!

David Marshall
 
Fast Forward Automotive Inc.
4356 Quesnel-Hixon Road
Quesnel BC Canada V2J 6Z3
 
Internet: http://www.fastforward.ca 	
Email: sales@fastforward.ca 	

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