My DIY EFI

[Chris Morriss]

In message <9608210045.AA07730 at wagner.mtco.com>, David Doddek
<pantera at pobox.com> writes
>My 2 cents on the simple pot based efi system.  
>
>There is a lot of talk out there, but has any one actually made one of these
>systems?  I have!!.  I first built an 8085 based system in college and used
>the idea of controlling the main fuel curve with pots.  I even had a dash
>mounted pot for changing overall ignition timing.  Kinda like being able to
>turn the distribuator while driving.  So I have the real experience to say
>that the simple system using just a few pots will work.  Out of curosity, I
>even cloned the system in the analog environment.  It only used a few op
>amps and some resistors.  With a little work, I could of made it temperature
>stable.  I took the simple system a bit further and am even selling it
>retail.  To the people that have used it, they like it.  I have had one on
>my own car for over 2 years now.  So I must agree, even though the fancy
>networks and programing languages can make for interesting extras, They are
>not needed to have a functional EFI system.  Remember the KISS principle.
>
Yes I have made a fuel injection controller using analog techniques.  It
was a simple M.A.P. sensed system giving one injection per revolution
with the fuel quantity determined by M.A.P. and water temp.  I had a
pot to set offset and one to set gain.  The offset pot was used to set
the idle mixture, and the gain pot to set max torque mixture.  I had a
differentiator circuit driven from the throttle pot to give a richer
mixture on acceleration.  It was tried on a 1 litre Hillman Imp engine
using Weber alpha injector housing elbows mounted on a twin 40DCOE
manifold.  A home made glass-fibre plenum chamber fed the four inlet
runners with the airflow control by a single throttle body.  It worked
remarkably well.  When I get the old Clan Crusader back on the road I'm
going to do a PCB for the circuit. (The Clan is a little known Imp
engined UK GRP sportscar)

I've only been on this list for 2 days, so please forgive me if this
topic has been covered hundreds of times before.

Bye,
-- 
Chris Morriss