[BRZCory]

Thank you for the info!

Attached is the FSM for the fuel injection, and it shows that for the By-pass air control solenoid valve (Or IACV for normal people) it has an "open" end and a "close" end. Open gets 7 volts, close gets 6. Granted, this doesn't tell us much about *how* it functions, so knowing that it's variable throughout the voltage range helps immensely! I was trying to figure out if it was some sort of pulsed stepper motor or something.

Page 71 has the drawing of that circuit, controlled by 1 input and 2 transistors. Vurry interesting.

Further edit, the factory setup is this: The valve is always open with no signals (and ignition/main relay on). Both circuits inside the IACV send power from the "power" pin (that's connected to the main relay) to the ECU. The "CLOSE" wire (with the ECU sending no signal) will energize the gate on the transistor on the "OPEN" wire, thus allowing current to flow, and "opening" the IACV. When the ECU energizes the "CLOSE" transistor, energy flows through that, and no longer energizes the "OPEN" transistor, thus closing the valve.

1 ECU control, 2 transistors (powerful enough to control the IACV, V=IR, 8v=I * 9ohms, I = 1.1amps, so a 2022 should be fine, TIP120 would be overkill, but still very fine ), and some creative wiring. I may just breadboard this later today, because it just seems cool, maybe with a 555 timer for PWM control.

Also, the "OPEN" wire is shielded, but I'm not sure why. The shield isn't connected to the ECU ground at all, so I'm guessing it's to prevent cross-talk between the 2 wires.

Now, to figure out how to attach it to megasquirt. I'll assume PWM control, but I need to do some more research on "Flyback" and see if it can control separate IACV OPEN and IACV CLOSE circuits. (This may be irrelivent now that I know how to do it with one wire)

I think that everyone should read through that FSM manual to get a basic idea of how the stock system works. It also provides *some* tables with rough numbers for where the factory engineers thought that the EG33 needed additional fuel and timing (just above zero degrees celcuis the enrichment map changes slope for instance). Lots of good info in there. But I'm sure most of you have seen/read it already.