going through the big change... Fuel only to wasted spark

[juki48]

OK, time for a change. I plan on starting the ghia one more time then pulling the MS2 and making the switch to wasted spark. I'm going to need a little help just to make sure I set it up correctly. right now I'm running fuel only using a filter on my coil- so I have MS2 setup as 12v hall/opto rpm in. I need to change to 5v optical in for wasted spark ignition. I will be using a 12-1 optical trigger in my distributor hole so it will be at cam speed. I have a logic level coil pack so I do not need ignitors.

I have just started reading through the MSExtra manual trying to make sure I get it right the first time. any advise or links to the best way to set it us would be great. I'm running MS2 V3 and the latest Extra code.

[Piledriver]

I'm not sure what your coils need, but if they run on 5v logic like LS2 coils, all you need to add is 2 ~1K resistors across the LEDs circuit providing a 5v pullup signal the LED driver transistors can pull down.
(The LEDs can stay)

IMG_0479.JPG

Then, using some 30 gauge kapton insulated wire (wire wrap wire) run the point where the 2 resistors in each circuit now join to 2 unused pins on your db37 connector to bring out to the coils + trigger side. (use a dollop of 5 minute epoxy at each end and every 20mm or so for strain relief)
You should do the epoxy as strain relief on every jumper, it keeps the wire from breaking at the solder joint.
It turns to ~dust under a soldering irons heat if you ever need to rework the board.
(It works well for this as it is poor glue, but good enough)

I don't know what dwell polarity you need, you set that in the software.

[juki48]

I got a subaru logic coil pack. common from around 2000-2004. from what I've read on MSExtra forums they run well on default settings, going low.

Pin 1 is the 5v input that fires the "1-2" coil
Pin 2 is 12v
Pin 3 is Ground
Pin 4 is 5v input for "3-4" coil
edit* looking at the connector on the coilpack, the pins are 4,3,2,1


so I will use the pullup resistor on the leds to drive the coil, still have to do some reading on the input signal from my opto sensor and I think I may need to make the relay coil output for my 914 tach. I seem to never fully know what I'm doing until I'm done soldering.

[juki48]

today I got most of the changes made to the MS. I put 1k resistors on the led's and ran them to ign and spr4, which already had a wire run to the engine but was not in use at the moment. I just need to pick up a 470ohm resister and it will be done. I hope

I started looking at the spark table. is there an easy way to generate a table? anyone have a conservative table for a mild turbo type 1? my fuel table goes from 700 to 6000rpm and 25 to 156 kpa, although I need to bump that up to 170kpa.

I'm going to try running my tach directly off the FIdle.

EDIT: what is the difference between 5V PNP drive and 5V logic drive? http://www.msextra.com/doc/general/sparkout-v30.html

[Piledriver]

~All the the circuits in a MS or pretty much anything else in a car (or most industrial controls for that matter) are controlled by switching ground...

The PNP driver is for the odd circuit that needs the power side actively switched for some reason, say a tach drive circuit.
You can use the 2 stepper drives but they won't work* if the circuit relies on an inductive spike to work (like many tach drive circuits)

5v pulldown supplies a very small amount of current at 5v, and grounds it to provide signal.
This is more or less a true logic signal, you can short it to ground and it will not hurt squat.

*it will work if you feed through a diode so the IAC driver internal diode doesn't short out the reverse spike.
The kickback spike is what many older tachs (and some ignitions) need...

[juki48]

well I've managed to totally confuse myself. I found two different instructions for setting up the tach input.

instructions 1 are here http://www.msextra.com/doc/ms2extra/build_manual.htm under 26 > Trigger input > Hall sensors only > 5V

instructions 2 are here http://www.msextra.com/doc/general/tach ... ml#crankin under V3.0 board - VR Input for logic input e.g. TFI, EDIS, GMDIS, LS1/24X, module

[Piledriver]

Are you using a hall input or triggering from a "TFI, EDIS, GMDIS,(or) LS1/24X module"?

[juki48]

I don't know man! I have a 5v logic signal. so the "VR Input for logic input e.g. TFI, EDIS, GMDIS, LS1/24X, module" got my attention. however the 1st link says "26) Trigger input: Remember you have already decided between VR, Hall or coil –ve. Note, Hall input covers all inputs like VAST, EDIS PIP, GM HEI, etc. "

[Piledriver]

You have a v3x mainboard so it's simply a matter of setting the jumper to route the signal into/out of the onboard VR/Hall compatible input amp circuits.
...No circuit revisions needed, the VR inputs are VR or Hall sensor compatible and adjust over a wide range.

The opamp circuits (whose design must vary for 5v, 12v and HV coil kickback inputs) are not needed at all, although you could use the opto (set up for 5v or 12v hall) and the second VR circuit for VSS and traction control for example if you had enough free CPU inputs.

The upside of a MS is that it is very flexible and you have choices---can be configured a thousand ways.
The downside is that you have a thousand choices to make.

[juki48]

ahh, so they are using two different circuits. now I'm getting it. maybe. I had set it up as the first example but the 2nd link, VR setup says "(Note that older directions suggested using modifications on the opto-isolator input for high-frequency use on toothed wheel install. This will often result in timing shift and is not recommended.)" so I'll switch to the VR setup. The original megamanual instructions were very good, explaining how everything worked while you built it. It seems like the extra manuals are scattered and confusing.

[Piledriver]

Reading the megamanual will screw you unless you are running the lame B&G firmware.

They are working hard on updating manuals, but the ms2extra/MS3 features are a rapidly moving target.
(This is also whey only V3 mainboards are supported with MS3--- One set of docs to write, if they allowed V2.2 boards it makes it 5X harder to write the docs due to all the possible mods)

What you are doing is pretty straightforward.

The opto worked OK for me on a ~low tooth count wheel, but you have a v3 board, so unless you need to trigger off an ignition coil don't use it for that. You have better options.

[Devastator]

I can send you my MSQ if you'd like. I'm running 10#boost on a 2276, burning E85.

[juki48]

I can send you my MSQ if you'd like. I'm running 10#boost on a 2276, burning E85.

are you still running this one?

when you posted that I remembered you sent my your msq a long time ago

[Piledriver]

Below ~83 KPA you should start cranking the timing, and you could probably get away with much more at low boost.
You can also use multiple tables in either axis for more resolution, but let's get you running first.

>50btdc at ~55 KPA cruise would be normal, and required to keep EGT/CHT down.(at least with gas)
The mix burns much slower at low pressure, and even slower when very lean as it should be at cruise.
The increased timing is NEEDED. You are not running a locked 009...

[Devastator]

I seem to recall that my advance numbers are quite a bit higher than that now. I'll have to check though.