My MS II Questions Thread
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My MS II Questions Thread
From megasquirt.info:
My 99 has a stepper motor IAC, correct?
22. Now you need to make a decision on the first 'optional' component: if you are going to use an IAC stepper motor with MegaSquirt-II, you must install a jumper from the hole marked S12C to the hole marked JS9 (+12C). These are on the bottom side of the board, on the DB9 side of the processor. DO NOT INSTALL THIS JUMPER FOR NON-MegaSquirt-II APPLICATIONS - IT WILL DESTROY THE PROCESSOR!!
If you are going to use a stepper style IAC (such as the GM IAC), you need to connect jumpers to bring the controller signals out to the DB37:
If you are going to use a stepper style IAC (such as the GM IAC), you need to connect jumpers to bring the controller signals out to the DB37:
- Connect (1A)JS0 (under the processor socket) to IAC1A (near the DB37 connector) - this brings out IAC1A on DB37 pin #25
- Connect (1B)JS1 (under the processor socket) to IAC1B (near the DB37 connector) - this brings out IAC1B on DB37 pin #27
- Connect (2A)JS2 (under the processor socket) to IAC2A (near the DB37 connector) - this brings out IAC2A on DB37 pin #29
- Connect (2B)JS3 (under the processor socket) to IAC2B (near the DB37 connector) - this brings out IAC2B on DB37 pin #31
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Note that for 2.88 code, the first thing you must do is set the ECU Type (under 'Fuel Set-Up/General') to match your hardware (MS-II or MicroSquirtTM), MegaTune will not let you change anything else until you do this. Do not change settings, expect the stim to work, load an MSQ, etc., until you have set the ECU Type (MS-II = 1, MicroSquirt = 2, the MS-II Sequencer will be 3). This setting applies to MS-II derivatives with code 2.88 or higher code only. ECU Type setting was inserted to head off the potential MicroSquirt problems due to the coils being turned on with the old default configuration. As of the 2.88 code, if ECU Type is not set, the code will put the ignition outputs in a safe state (cycling the rpm from 0 to 8000 rpm, and also flashing the fuel pump LED) and wait until a known ECU type is put in by the user.
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what should I do for the ignition outputs? I want to use the factory coilpacks. Should I do this:
This is for a 90-97, but would it be the same on my 99? My ignition inputs will be different, as I'm using the stock sensors to trigger the ignition.
Taking Control of the Ignition --
Decision time-- use the stock ignitors or use dual VB921 coil drivers. I'm going to document both options for you here, but I'd recommend using the stock ignitors as it's simpler, and they will properly trigger your tachometer.
Only use one method or the other for spark output, don't try to combine the two!
Option 1: Spark Output to factory Miata ignitors: (Recommended)
Parts Needed for PCBv3 Output Mod using factory ignitors: (2) 1k 1/4w Resistors
Next use two 1k ohm resistors as pictured below, along with two bits of wire to bring the signals out to the DB37. This will condition the board to use the stock ignitors and coil packs. Take each resistor and cut off all but about ¼ of an inch lead on each side, hook both ends and loop them around the pins that were already soldered. The picture below shows where they go. The resistor goes from the 5v side of each resistor to the negative leg of the respective LED. This is then brought over to the db37 with two lengths of wire (one for each). The top resistor goes to IGN and the bottom resistor goes to IAC2B.
When wiring up your ECU later: Spark Output A will come out on pin36, and Spark Output B will come out on pin31.
Picture of board.
http://www.diyautotune.com/images/ca...utput_mods.jpg
Decision time-- use the stock ignitors or use dual VB921 coil drivers. I'm going to document both options for you here, but I'd recommend using the stock ignitors as it's simpler, and they will properly trigger your tachometer.
Only use one method or the other for spark output, don't try to combine the two!
Option 1: Spark Output to factory Miata ignitors: (Recommended)
Parts Needed for PCBv3 Output Mod using factory ignitors: (2) 1k 1/4w Resistors
Next use two 1k ohm resistors as pictured below, along with two bits of wire to bring the signals out to the DB37. This will condition the board to use the stock ignitors and coil packs. Take each resistor and cut off all but about ¼ of an inch lead on each side, hook both ends and loop them around the pins that were already soldered. The picture below shows where they go. The resistor goes from the 5v side of each resistor to the negative leg of the respective LED. This is then brought over to the db37 with two lengths of wire (one for each). The top resistor goes to IGN and the bottom resistor goes to IAC2B.
When wiring up your ECU later: Spark Output A will come out on pin36, and Spark Output B will come out on pin31.
Picture of board.
http://www.diyautotune.com/images/ca...utput_mods.jpg
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My opinion: you can wire the cam and crank sensor inputs the same way for an NB as an NA. Yes, the sensors themselves are physically different, but electrically they are the same- they all use open-collector outputs that expect an external pullup and give you a closure to ground when "active".
The ignition outputs as wired per the assembly instructions will give you a 5 volt active-high trigger. A while back in the EMU forum there was great debate about this topic with regard to the possible destruction of the 1.8 ignition coils. I determined by observation that the 1.6 igniter requires a 5 volt signal, and others observed that 1.8 engines of various years all seemed to use a 12 volt ignition pulse to the coils.
What size wire goes into the db37 that comes with the MS? I got 18 but it dosn't go into the pins on the plug.
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