Why not just use a 555 timer IC? ;-)

[Peter Wales]

This reminds me of the first EFI system I ever built. The system built by
the professionals didn't work in practice on the Saturday afternoon for
Sundays race, and so they gave me the job. I had 23 hours to make a system
for a Mitsubishi Starion race car. I knew nothing of EFI and it was Saturday
evening so all parts had to come from the spares box. The car had a pressure
sensor and a good ignition pulse so I divided the ignition pulse by 2 to get
a nice injection trigger signal and then fed the prssure sensor signal
through a pot into 2 Cmos 555's analog input. The output went into driver
Darlingtons and that was it. The mixture was adjustable from the dash and
the driver has an egt to tell him what was happening.

We had no idea what a good egt was so we said keep it under 1000 deg c.
Well, he didn't win the race, but his performance was good enough to get him
noticed by the TV cameras and Murray Walker got excited about him overtaking
things and that was enough to get us a budget for the next season.

Ah, the good old days.......mutter mutter mumble mumble
Peter Wales
President Superchips Inc
Chairman Superchips Ltd        "Timing is everything"