It would be handy if you could test your EFI with out
having it on the engine. In other words in the shop.

What you need is a Crank Angle Sensor AKA CAS simulator
and a hand vacuum pump for the MAP sensor. The vacuum
pump is no problem as they can be had for around $20 in auto
parts stores.

The Crank Angle Sensor simulator is just a variable
frequency variable pulse width generator. Unfortunately
manufacturer of these device want several hundred
dollars.

It took me  a few hours to make one suitable for testing
an EFI system from parts I had lying around. Nothing
you can't find in Radio Shack. I was only interested
in 7500 RPM as that is worse aircraft engine case so this one
is fixed frequency... fixed pulse width out. With a couple of
pots it could be made variable frequency.

Here are all the tools you need and a picture or
two of the device.

If enough people show an interest I will do a pc board
and/or an assembled unit. My guess is $50.


-----------------------------------------------------
Ops I left out a couple of parts in the schematic.
Here is the corrected version.

BTW your Atmel computer makes a great 8 channel 1 Mhz oscilloscope for
digital 5 v signal levels such as found in automotive
computer systems. Real scopes costs $1000's. If you doubt
your CAS is working check it with your Atmel.

Here is all you need for a program.

Sub Main()
 Dim val as Integer
do
val = GetADC(82)  'pin 82
Console.Write(CStr(val) &",")
loop
End Sub

The data comes out in a string of numbers.
254 the the signal is high. Zero or close
to it... the signal is low. You can actually
measure the amplitude and rise time of the pulse. The
pulse amplitude will be some where between
254 and zero.

Paul Lamar