Clay - the 3 relays are for main power, fuel pump and fast idle solenoid.

Charlie - I bought the relay board mainly to avoid hacking the OE harness early on. I'll get extra OE injector and distributor harnesses to use for the MS modification. I may not use the relay board when all is working, but I want to be able to easily get back to OE if things don't work as planned.

Since MS does not yet have IAC stepper motor control beyond CLT feedback, I plan to use the FIdle relay to control a secondary idle air supply when A/C or P/S is in use.... let the ECU control the IAC for temp and add more air via a solenoid when the A/C compressor or P/S pump kicks in.... don't know if it'll work, but it's what I want to try.

Frank

Back again,
MS2 will run the stepper motor, Need to change the wireing to the stepper since the commons need to be grounded rather than supply for the MS driver operation.
MS1 extra will run a Ford or Bosch idle valve. I machined a block to mount a Ford idle valve onto the Mitsu throttle body. Works fine.

Frank,

no dice on that elbow, wrong sizes and thread pitches. Sorry I couldn't help.

Anyone who thinks this will be easy should think again. <img src="/forums/images/graemlins/baby.gif" alt="" />

Here's the relay board, now enclosed in a case that can be mounted in the engine bay with a measure of weather protection. It did take a little sanding of the board edges to fit, but it looks like it'll work ok:


The ECU main board is nearing completion, but I'd like to meet the fellow that (according to published advertisement for MS) can assemble one of these in 6-12 hours and get it to work. <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/scared.gif" alt="" /> Soldering is one thing, but understanding what a computer geek is trying to explain to a mechanic is something else... somehow the language and culture are quite a clash - but ultimately have to be merged in order to know what the heck needs to be done. Here's the half-finished board running on the stimulator:

And after much hair-pulling and finding out that the downloaded firmware was not the complete version I needed, I finally got the correct files and burned code to the processor - here's a shot of the real-time display running on the laptop:


Charlie - since you've had experience with Mitsu and MS, hopefully you can steer me in the right direction on a question that's bugging me:

I'm trying to figure out if I should use direct coil control - or use the power transistor with the OE coil. I started populating the board with the high current ignition driver circuit, but it seems to me the other way 'round makes more sense. I know there are issues with figuring out the rising/falling edge, high/low trigger, but which way is actually better? I don't mind the figuring and head-scratching if the low voltage signal is best. It seems to me to make more sense to use the low voltage signal to the power transistor along with the LC filtered signal to the tach that's on the OE setup. What's your opinion, and is one method better than another for full spark control on forced induction?

Oh, wouldn't there be more protection from burning up the coil if I didn't use the high current ignition driver circuit for direct coil control?

Frank

Does "direct coil control" mean the same thing as distributorless ignition?

No - that's one of the geek-speaks I was referring to in the earlier post. Actually, it's a fairly simple term, once you recognize that the alternative to 'direct coil control' is...... 'indirect coil control'. If the coil is triggered by the ECU>ignition module>coil, that's 'indirect coil control' because the ECU triggers the power transistor and the transistor triggers the coil, although it's never referred to as such in the manuals. If the coil is triggered directly from the ECU, that's 'direct coil control'. Simple, eh?

Not really....... if 'indirect coil' control is chosen, you have to figure out if the square wave signal coming off the module is inverted and what dwell setting is designed into the transistor.... so there's another issue down the road in configuring the ECU to use the falling or rising edge of the square wave signal as the trigger. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

With an optical sensor, direct control is suggested for simplicity - but my cause for worry is the amount of current required within the ECU trigger circuit - you have to build an extra circuit to handle the load.

I'm concerned with the possibility of coil burnout if the ignition is on and the engine isn't running for a while. I've blown up one coil in a boat that way by not using a dropping resistor to reduce power at the coil... it wasn't a pretty sight with oil everywhere and the possibility of a bilge explosion/fire was downright scary.

Anyway, just as I thought I had the MS issue limited to two choices for coil control and all figured out, I discovered that I could use the 'direct coil control' high current driver circuit to trigger the ignition module, in effect giving me a high current indirect control. <img src="/forums/images/graemlins/lol.gif" alt="" />

Man-o-man......... <img src="/forums/images/graemlins/evil.gif" alt="" />

Frank

Interesting. I wish I'd payed more attention before.

So, wouldn't MS have included a switch in the circuit to discontinue power to the coil circuit without some kind of RPM input? I'd be rather suprised if that were the case.

Personally, I would choose something rather indirect just so there's a little more buffer between the coil and the ECM in the case of a bad field collapse... But that's just me. Plug wires do go open on occasion.

That's exactly the question I'll be digging into during tomorrow night's learnin' session. <img src="/forums/images/graemlins/kewl.gif" alt="" />

I've had enough brain food for tonight...... <img src="/forums/images/graemlins/lol.gif" alt="" />

Frank

Hi Frank,
With a dizzy I have set up the stock dry coil and ignitor. Since MS does not switch power to the ignition the way the factory does you want to provide the ignition and any 12 volt sensors power from the same circuit that feeds the MS.
The trigger wiring gets 12 volt power will just needs a 5 volt pullup internally fed directly to the main chip with a 1K protection resistor,this means there is no VR or Opto circuit.
With the MS2 the rising / falling of the trigger is selected in the sofware making this part very easy.
The output gets a 5 Volt pullup when using the stock ignitor.

Thanks, Charlie - I think I'll try the high current driver that puts the ignition module on the MS2 board - no sense in redundancy of an ignition component or looking for other trouble.

The MS2 manual does suggest that the VB921 driver circuit is probably the best solution for most optical distributors..... it was the word "most" that I didn't trust. <img src="/forums/images/graemlins/wink.gif" alt="" />

Frank