Are MSPNP Daughterboard Schematics Available?
 

I haven't been able to locate one of these. As I contemplate mods, it sure would be handy. Right now, I'm especially interested in the MSPNP9093 circuit that is used to drive pin 1J on the external connector (A/C relay).

its an extremely simple circuit.

when the A/C switch is grounded, it trips a relay which grounds the a/c compressor.

Understood. Going off the FSM schematics provided by JP here (https://www.miataturbo.net/showthread.php?t=20954):

1. The A/C switch provides a ground through a thermoswitch to 1Q (LG/B); and
2. 1J (L/B) provides a ground for the AC relay and the Cooling Fan relay to activate the AC Clutch, AC Fan and Cooling Fan.

I'm interested in what is between 1Q and 1J. Is it just a trace? The reason I'm asking is that right now I've setup table switching to increase idle spark advance when the AC compressor is engaged (thanks, by the way). However, I'd like to see if I can also use table switching for switching EBC duty cycle maps based upon a WI input on a non-interference basis. Just brainstorming.

I'm sure I can reverse engineer the circuit, but if someone knows what it looks like, it would be much appreciated.

It is not a straight through trace. There is a small transistor circuit on the 9093 daughterboard that grounds 1J when the a/c command switch is depressed and pulls 1Q to ground.

Do you know if the TPS factors into the circuit at all?

No, it's not. Is that what you are trying to do; have it cut out at a certain TPS/RPM?

It's pretty much, IJ through 1K resistor to a Pn2222 base. Emitter is on ground. Drain goes to 1Q.

Note: That is without ever having looked at it, so I'm probably wrong about the circuit.

Arrrghhh!! Never mind.

The boost table switching only works on closed loop targets, not open loop duty cycle. I was hoping this could be a workaround for lack of functional closed loop EBC on MS1.

Perhaps the best way to handle WI safety with the MS1 is external to the squirt . . . basically, default to standard wastegate boost unless WI is on. If WI is on, then allow pulsing of the EBC solenoid.

Well if you actually use the MSI for WI, it sprays based off the VE fuel table. Then you're simply supposed to pick a nozzle sized 15% of the water to fuel ratio. So like if you had 550cc injectors 4 * 550 = 2200cc of fuel, so then you'd use a ~333cc/min nozzle.

Joe Perez had a cool WI failsafe, you should look at what he did.

You could probably figure out something that if the EBC is active, like using a physical 2-way switch, then the pump gets power, otherwise the fail to both wastegate and no WI.

I use a simple switch on the EBC signal to cut power to the solenoid to fail to wastegate when I only want to run 10psi vs 15psi.