3.2 ICV question
 

Hi Pelicans, I am well into my megasquirt EFI project and coming up with many questions. Todays pressing question is, what kind of "valve" is the 3.2 Idle Control Valve. Is it a stepper motor or just an open closed switch?

thanks guys

If I knew I'd tell ya, but I don't, so you'll just have to settle for a bump,

ianc

Ok
 

Nudge nudge, wink wink, say no more...

Not sure-it definitely isn't either "open" or "closed"-it occilates between those states. Does that help?

Ok
 

Thanks Greg, sounds like a stepper motor?

From the reading I've done (no experience) the DME sends a variable pulse width signal (ground closures) to the rotary solenoid on the valve. This current pulse train creates a magnetic field in the valve (looks like + and -, must have a default position at neutral?). The period of this pulse train is fast enough so that the dynamic variables in the valve (inductance, inertia, etc) average it out and it is a somewhat steady value i.e. it stays in one place.

The idle speed is a closed loop control with the DME. The DME doesn't "know" where the valve is positioned it just "knows" it wants more or less idle speed and reacts accordingly.

It's a PWM valve just like the VW's...fully supported with MS but may need a higher rated transistor to handle the current, especially on the V3 ECU's. Talk to Dave at www.fireandfuel.ca for more information as he knows these systems inside out.