Barson Wrote:The thing DOES fully open on crank.
I've tested both windings and the thing does flip back and forth at you would expect.
The thing i don't understand it why the motor would be open as the idle speed switch is disengaged - shouldn't it shut and allow the venturi to meter the air as you say?
Is it the thermistor that's telling the ECU that the engine is cold so the ECU it keeping the motor open?
I'm perhaps misunderstanding the way the motor works with the engine. I thought it was ust a matter of the thing openning fully and shutting fully depending on what the idle speed switch does.
One thing I should mention is that the metering flap isn't shut on idle - it hovers just slightly downward. also with the air filter housing off the flap (or what's beneath the flap) makes an awful sucking sound like a vaccum cleaner sucking up a puddle if warm vomit.
I unplug the motor and it diappears. any ideas?
Sounds like ISCV is ok if you have done the tests.
The ISCV motor is position controlled by the ecu pulsing the windings quickly.
http://www.picotech.com/auto/waveforms/ ... otary.html
Using this control the valve can be positioned at any point.
If the switching rate is equal (yet anti-phase, they don't switch together) to each winding then the valve will appear stationary. If one side is switched slightly longer than the other then the valve will move in that direction accordingly.
Where this valve is positioned ie how far open or closed it should be is given by the switching rate at the ignition coil ie the rotation speed of the engine.
The engine idle speed set point is usually about 775 +/- 50 rpm
If the actual engine speed is higher than this figure then the ISCV will be control closed slowly.
If the actual engine speed is lower than this figure then the ISCV will be controlled to open slowly.
If the engine is cold then the ecu will raise the engine idle speed set point to approx 1100rpm to 1300rpm depending on the resistance of the thermisotr.
I have not seen the position of the ISCV when the throttle switch is disengaged but would have thought it would be either be positioned half open or fully closed.
I have a spare working idle speed ecu if you want to try it out.
The air through the ISCV is metered by the ventury so the fueling is correct. The air path through the ISCV comes from the brass pipe under the manifold at the back into the venturi housing and then goes past the throttle plates.
I am not sure about the noise you mention. Without listening to it myself I couldn't say if it is normal or not.
Note where your brasss screws are then wind them all in counting the turns so they can be returned to the original position.
See what effect this gives on your car. The gurgling noise may be the air by-pass through the channels past the throttle plates. The brass screws adjust the amount of air through these channels and could be wound open too far hence the sucking noise.
Worth a go. A bit hard to tell without seeing the car.
Good luck.
NickT.