IAC

[peter paul fenske]

Hey Gang

Another thought why not use the vacum pwm modulator 
that gm uses to control egr ccp ect. xrysler also uses em

A double 555 cct can produce an adjustable pwm from 0 to 100%
Use a LM2917 as a tach to voltage converter and then
control your idle via a ref voltage. Gee we could use 
a ctc to alter this ref as well as ac ps ect

have fun: peter

At 02:50 PM 12/8/97 -0600, you wrote:
>Ok, here's the big question:  Why do you need 3 rpm levels?  Howz about
>just normal idle and high-idle, such as 1400 rpm to keep the alternator
>chargin' good for winching, etc?  I would look for a plug in your intake
>manifold and try unscrewing it and holding your finger over the hole to
>see if you can actually vary the engine speed that way.  I know that
>unless that plug is close to the center, the engine will not really
>increase in speed, but it will run kinda crummy.  but I would try it out
>first!  
>-- 
>Andy Quaas
>
>