Tuesday, September 20, 2011

The 3-wire ICV

MS3 has native support for 3-wire ICV's, so no more conversion circuits.  I had my motor started and idling, but the idle was horribly unstable and oscillating like crazy.  I activated the "Test Idle Valve" feature and reduced the PWM all the way down to 0% but it was still idling like it had a massive vacuum leak. 

I physically pinched the ICV hose and the idle fell to acceptable levels.  Then stalled..

I had an ICV control problem, I only had control on the "open ICV" wire so I couldn't get below 50%.

After continuity checks and more trouble shooting, I finally figured-out that I had the port for the second idle wire wrongly configured.  Chris' wiring chart has it running through the VVT pin (why?) but I had the wire configured for the IDLE pin.

Once I got that straightened-out I found that the motor idled nicely at around 40% on the ICV.


  1. So you're running it through the VVT wire instead of IDLE?

  2. the choice of ports was random. there's only one "idle" pin, and te other PWM outputs are all identical. it really doesn't matter what the label is - honestly, I think the label names makes the pin use more confusing than it needs to be.

    also, mine was for an M20, so I don't have VVT.