MicroSquirt.com read only forum (Jan.15,2018)

I finally abandoned the MS-I and purchased the Microsquirt. Now I am all wired up and have fired the engine a few times, but I am increasingly having troubles getting it to fire and I cannot keep it running for more than 30 seconds at a stretch. I am triggering from the - side of a coil on a dual coil, lost spark, inline 4 cyl Kawasaki motorcycle. I am trying "fuel only" for the time being while retaining my DYNA2000 ignition system and coils. When cranking, I may crank a LONG time when suddenly I get an RPM signal (say about 150RPM) and the bike will fire up. THen the signal will go away just as suddenly. No signal, no fuel pump (except the 2 second initial pump), no cranking pulses, and no starting. The ignition system seems to have continuous power through the entire episode. I have it wired OPTOIN+ to the -coil for cyls 1 and 4, and I have the OPTOIN- wired to ground with a 4.7k resistor. The stock tach is also hooked into that -coil wire as is the cruise control (though the cruise is not being powered up at this time so it SHOULD be a non-factor).

MY DYNA2000 ignition has two wires coming from the case that are supposed to be tach signal wires. One of them gives two pulses per cycle and the other only one pulse per cycle. I have tried hooking these up as well by hooking them to the OPTOIN+ wire while connecting the OPTOIN- to battery ground. I got no signal from either of those so I chose the - coil wire. What am I doing wrong? Here's a brief msl file.

Your problems are in the trigger± part of the datalog, when it does run. So something is not right in your settings or you are getting noise issues. There have been a few posts recently with "fuel only" set ups & triggering by coil, just have a look at those, and I'm sure the answers will be there.

Thaks 24C, but I have been looking at them BEFORE I posted and have tried every wiring suggestion so far that I can find. If something is wrong in my settings I don't know what it is (which doesn't surprise me, but...). If the answers are there I am just missing them. Newbies ain't we the pits?

So far I have tried:

OPTOIN+ to #1 coil's -side and OPTOIN- going to switched 12v+ through a 4.7k resistor. That DID start a few times. Not now.

I have tried OPTOIN+ to #1coil's -side through a 100kresistor and OPTOIN- to 12v+ with no resistor. NADA

I have tried OPTOIN+ with a 24v Zener (with the band toward the coil) connected to #1 coil's -side and the OPTOIN- connected to switched 12v+. NUTTIN'.

I have tried OPTOIN+ connected directly to the TACH output of my DYNA2000 ignition and the OPTOIN- connected to ground. NADA.

I have tried re-wiring all of it each way again using shielded wire with the shield connected to ground. NADA, NUTTIN, ZILCH, and ZIP.

I did an injector test in Studio giving them 14 pulses at 6PW. I then switched back to normal and the bike fired on the fuel for a few seconds. If I can get this thing to trigger the injectors it will run. My spark is good and on time. This is fuel only and I must have something set wrong or...

I read somewhere sometime about a TPS issue that must deliver under a certain voltage to stay out of the CLEARING mode and that it didn;t matter what MT said the TPS read, if that voltage was wrong nothing would work. now I cannot find that again to study up on it. Do you know what I'm talking about (if so it will make one of us). Thanks for trying to help me. I am getting pretty punchy about know. LOL

Well, after many more hours of trial and error I am thinking the Microsquirt has given up something in the OPTO circuit.

presbychuck wrote:So far I have tried:

OPTOIN+ to #1 coil's -side and OPTOIN- going to switched 12v+ through a 4.7k resistor. That DID start a few times. Not now.

So go back to this, and use TS or MT and check that you have RPMs showing under cranking, if not take a datalog with say the plugs out, and hopefully you'll see something reliable and steady RPMs on the gauge, but once your trigger± is stable, no big increasing or decreasing changes you should have reliable "tach". The next thing is to go over your fuel settings and get a reliable start.
You can also post your .msq and somebody will check it out. I am away to France 'till the end of the week, so hopefully somebody will respond.

PS The OPTO circuit is optically isolated and pretty robust, so don't assume it's down.

Well I've tried connecting the OPTOIN- to ground and then scratching the OPTOIN+ wire to the + battery terminal and haven't registered any RPM. That leads me to think I'm not apt to. I've been back with this thing for hours at the OPTOIN+ to -coil and OPTOIN- to 12v+ and haven;t gotten a single blip on the tach in MT. I can pulse the injectors in the test mode and the bike will run shortly on that shot of fuel. But even when running it shows nothing on the tach in MT though the tach on the bike registers fine from the same circuit.

It turned out to be a blown resistor on teh Microsquirt board. Matt soldered me up a through board replacement that should cool a little better. Then, I installed an extra resistor and diode on my OPTOIN lines and she picks up very well and the signal appears clean. Thanks Matt, as always... DIY rocks.

I now have the bike running and am underway with the next batch of hurdles... tuning.