Mitsubishi: 1993 1.5 High Idle Mirage/Colt

"star raider" <com> wrote in message
news:.. 

I'd say you have a vacuum leak somewhere. Look at the small hoses for holes.
Also, there's an air idle adjustment on the throttle body. Its a phillips
type screw under a 10mm round black cover.

Stewart DIBBS
www.vysor.com/lancerproject

In follow up,

There are no vacuum leaks...all checked spraying with gum out.

The IAC is being told through the closed loop logic of the computer to open,
and oscillate.
I did much reading and troubleshooting on this and took it to the shop so
they could put the computer on it. The error codes are pointing to the IAC
but is still is a best guess....bad wiring, bad ground could be lurking as
well.

I scrutinized the coolant sensor, Oxy, and Map sensors buy litterly tapping
into the feedback wire that goes to the computer and watched the voltages.
The oxy was under 1 volt, the map sensor change at different reves and
coolant output voltage changed as it warmed up. all the connectors were
checked and cleaned...no sign of oxidation either.

Every thing points to the Idle control motor/motor position sensor/switch.
I already took the plunge and replaced the TPS after detecting some
intermittency/gaps while ohming it out and rotating it. ouch $$$160.

After starting the car, I disconnected the wiring to the IAC, opened the
motor/value plate and manually closed the valve with my finger....And it ran
Great. If I plug the harness back in it stays where I left it, but it resets
when you restart the car.

This tells me that the motor closes/resets at start, to find the home
position, then proceeds to open back up. then the high idle and oscillation
begins. The oscillating idle (while high idle) tells me the motor position
sensor contacts may have a bad spot in it, or some of the motor coils have a
hard time stepping back towards the closed position.

Next step is the ohm out the wiring to the IAC and motor position sensor and
switch or find a junk yard part....they want $260 for the new assembly.


This has got to be a re-occuring thing out there......any one else figure
this one out?

The cost of these parts is way out of proportion to any other American
car....and don't tell me there is something Better or longer lasting about
them... Foreign imports mark up the parts a minimum of 3 times the landed
cost in the US.




"Stewart DIBBS" <com> wrote in message news:...