For some reason my MY97 STi won't idle. I've swapped the idle control valve complete and still it won't. It idles when cold, but as soon as it warms up it drops out.

Apexi ecu commander shows open O on ICS and 0.57v on throttle position, is this correct? Thinking that the control valve isn't getting a signal to operate if the tps doesn't tell it to?

Checked ohms of old and new solenoids and both give the same readings across any pair of pins.

 

Hi Gerry, my car 97 uk has begun to have idle issues, I adjusted the ICV, it idles ok when warm, but is poor when cold with a reluctant fast idle(choke). My car from memory had 0.47v on tps. I would be interested to see if you manage to cure yours before I do mine.

Andy

 

Trying to find what volts should be going to the icvs on idle. Any ideas Andy?

 

 

The icv is a soleniod, so I would expect a rapidly adjusting voltage to maintain stable idle. This voltage probably wont deviate alot.

 

Is your commander giving the correct water temp reading? Could be a dead water temp sender

 

Didn't check that. I'll take a look in the morning.

Just found the equivalent page of above for MY97 and tps voltages are different. closed 0.5v; open 4.3v both =/-0.3v

 

ICSV isn't just open/close. It's a controlled opening according to engine load, temp, a/c, etc.

 

ICSV open end 1, max - 13, min waveform
close end 13, min - 1, max "

What does that mean

 

I cant remember if there are three wires or two going to the ICV. iI it's 2 wires then the voltage will pulse rapidly between 0volts and what ever it needs to control idle upto supply line 5v or 12volts. If it's 3 wires then the voltage should swing postively and negatively to control idle. Time to dig out my oscilloscope and see whats happening.

Andy

 

3 wires, presumably to drive both ways and still think it's a stepper motor rather than a solenoid, that way it can maintain partial positions rather than open/close.

Jay, Water temp on commander is as you'd expect, gradually rises with engine warm up.

 

Question, what do the other pipes do, that are connected at the bottom of the ICV?

Andy

 

They're part of the water system, to heat the valve? There a bi-metalic device in there.

 

Idle is now back where it should be

It turned out to be the connector to the 02 sensor. I guess that the heavy rain of late has found it's way into the connector and caused a poor connection. Gave it all a liberal spray of WD40 and it now idles sweet as a nut.

Odd that it coincided with my trip into the tyres a couple of weeks back

 

Hope there wasnt much damage! Good news you have sorted the idle problem. By the way do you run your pfc with the O2 sensor switched on or off in the sensor menu?

Andy

 

Why damage? I presume the 02 sensor is switched on, but don't know for certain.

 

The tyres point, sounded, well to me, you had run off the black stuff into the rubber stuff.

Andy