Ke-Jetronic theory.(explained)

[amalventano@sc.rr.com (Allyn)]

> Well the thermotime switch turns on the 5th injector if the temperature of
> the engine block is below a certain temp ( ce-efficient of linear
> expansion switch, and if there is fuel flowing thru it. ( I believe,  this
> is a odd little detail, it just normally effects starting. )

this works kinda like the blinker bulb in your christmass lights. if its
cold enough, a temp sensitive contact closes. when current goes through the
contact, it heats it to some degree, causing it to open. related to cis-e,
the thermo-time switch contains the contact which carries current to the
cold start valve. if its cold enough, the contact is closed, and goes
through a cycle of opening/closing as it heats/cools during cranking
(switching the cold start valve on/off like the christmass lights are). the
colder it gets, the longer it takes to heat up the switch contact, resulting
in longer pulse width in colder temperatures.

> It is prolly an IGBT,
> but that depends on when your car was made it could be a PNP transistor.

high power switching mosfets. newer units may use igbt, but that technology
wasnt cost effective when out cars were built.

> (depending on your
> car -- 16v dont have 3 wire O2 sensors, 8v's do).

every 16v i've had uses a 3-wire, as well as digifant 8v's

> If it needs to adjust it, it changes the rate of the frequency
> valve on your airflow plate buzzes at.

this is for 8v, isnt it? 16v's dont have frequency valves. for 16v it varies
the DPR current, which is DC and has no frequency. varying DPR current
affects internal control pressure, effectively changing the 'gain' of fuel
output vs. air flow sensor plate position (in the end, changine mixture).

> It also adjusts the idle with the
> idle stabilization valve. Im not sure how, but it has to do with how air
> get recirculated.

yup, it bypasses the throttle valve. as for how, it varies the pulse width
of an ~400 hz square wave going to the ISV. the valve inside the ISV cannot
physically move that fast, so it sits at the average voltage present. longer
pulse width leads to higher average, opening the valve further.

Al