In search of good ignition input signal....SOLVED (mostly)

[EWflyer]

I'm working on a Kawasaki EX-250, Fuel Only, MicroSquirt on 2.890

So far I've been trying get the bike running on an Ignition Input from the bike's VR. When I view the datalogs from my cranking/starting attempts I'm seeing RPM readings that are strange (very high), the RPM trace spikes up and down very erratically, and the TachCount keeps resetting to zero.

datalog200911221809.msl

EX-250 datalog

(391.04 KiB) Downloaded 78 times

I have to admit that I've never truly understood the Ignition Input portion of this MicroSquirt intall. I've just done what "seemed" right with the wiring and and the parameter settings in my .msq and hoped it would all be correct.

EX-250.msq

EX-250 .msq file

(25.08 KiB) Downloaded 78 times

My question here is: If I can't get the VR signal situation corrected, what are the alternative sources for Ignition Input? I've read about (but don't understand) triggering directly off the coil. This apparently uses the OPTOIN rather than the VRIN.

Help me please, I'd rather be riding!

[Matt Cramer]

Try triggering off the opposite edge, or switching the VR sensor wires around, and see if that helps. That trigger wheel looks like one way would work well and the other way would be troublesome.

[EWflyer]

Try triggering off the opposite edge, or switching the VR sensor wires around

I understand how to change the triggering, that's in MegaTune on the "Base Ignition Settings" menu. But as far as switching the VR sensor wires I'm not so sure, and I've been wondering if I've made the correct assumptions about my bike's VR wiring. Here's a stab at showing you what I think I'm working with.....

Here are pictures of the bike's rotor, which turns at crankshaft speed and has several "teeth" or "lugs" on its outer perimeter.





Here's a picture of the Stator assembly that it rotates around.



Two wires, one Black and the other Yellow come from a sensor positioned at the edge of the rotor. These two wires are routed from this rotor sensor to the Ignition Control Box as shown in this wiring diagram. (Don't worry, I at least know the difference between the Alternator wiring and the Ignition sensor wiring)



Am I right in assuming that the two wires that come from the Pickup Coil (#13 in the picture) are the VR outputs, one for Cylinder #1 and the other for Cylinder #2? It's a "wasted spark" type of engine so I've assumed these two wires each transmit one pulse every 360 degrees of crankshaft rotation, with the black wire and the yellow wire pulses being 180 degrees out from each other.

That's the assumption I've worked under so far and I've wired the yellow one to the MicroSquirt VRIN1+ (Ampseal Pin #32) and I've wired the VRIN- (Ampseal pin #33, Coax shield) to the Black with yellow (BK/Y) ground wire that comes out of the Ignition Control Box (#14 in the picture).

If this wiring is all correct then I guess I can move forward with trying to fix my problem by re-configuring the Ignition parameters in MegaTune. But if this wiring is wrong I'm back to square one.

[24c]

Rotor2_annotate.jpg (27.77 KiB) Viewed 2086 times

Hi again, this is why you cannot use your VR sensor...you have a non conforming trigger wheel. The long slot is not catered for.
AFAIK, you have to use the coil side to drive the "tach" for the MicroSquirt in your application now. If you look at the previous post with the reference to the coil wiring options using OPTOIN etc, and then read the manual you should be wiser. The only issue AFAIK is you can get flyback "hurting" the inputs, which is why some folks fit resistor here, although the OPTOIN is optically isolated. I wish I could help more, but I have no experience of driving the MicroSquirt via a coil feed.

[EWflyer]

Hi again, this is why you cannot use your VR sensor...you have a non conforming trigger wheel. The long slot is not catered for.

Yes, I now see it that you are exactly right!

I had time on my hands today (about 4 hours) and I've been sitting here in front of the computer puzzling over my Ingition Input situation for that entire time. Just a few moments ago I finally realized how my Kawasaki EX-250's VR sensor actually works.

I had gone online to eBay (in the motorcycle parts section) and collected several more pictures of the EX-250 rotor. With 7 or 8 different pictures to look at I was able to realize that it has two short "lugs" and one long "lug." I realized that the Ignition Control Box uses the long "lug" as a discriminator signal. If it sees the long "lug's" signal go by between short "lug" signals it triggers Cylinder #1 ignition and if it doesn't see the long "lug" between short "lug" signals it triggers Cylinder #2 ignition.

When I made this discovery I knew my prior post in this thread was complete crap so I logged on to delete it but the system informed me that I couldn't delete it now because someone (you) had replied to it. Thanks for the feedback/analysis of my problem.

Now I know the direction I have to take to get this thing running.

I've got to figure out how to configure for OPTOIN+ and OPTOIN- but the forum threads you directed me to the other day are a little confusing with Bruce Bowling giving a solution involving the coil ground wired to OPTOIN+ and 12 volt with a 4.7K resistor wired to OPTOIN- to produce an ignition input signal based on the flyback pulse. But "A2TURBO" replied that it didn't work for him. However, I'm willing to give the 4.7K resistor thing a try as long as there's no chance of damaging the MicroSquirt.

[24c]

When I made this discovery I knew my prior post in this thread was complete crap so I logged on to delete it but the system informed me that I couldn't delete it now because someone (you) had replied to it. Thanks for the feedback/analysis of my problem.

It's good to leave mistakes in, others can learn as much from this, then getting it right all the time

So in the microsquirt.info it explains in the wiring section how to use OPTOIN+ and OPTOIN- and it looks like Bruces recommended method. You can try it and see if it works, and if it doesn't try the other way. It has to be less problematic, than what you have been doing so far.

Another option is get another flywheel and machine the long slot off it, reconfigure the MicroSquirt and go ignition and fuel.

[EWflyer]

Now that I'm settled on the idea of using the OPTOIN+ and OPTOIN- solution to the Ignition Input problem, I've got a question that will show you how little I know about electronics.

I really don't know anything about resistors. The extent of my expertise is going on an internet website for a resistor calculator program that takes the basic parameters of what you're trying to put together (volts, amps, etc.) and gives the correct resistor to use.

I don't know if resistors get hot when used in an application like my OPTOIN circuit. So when I solder this 4.7K resistor to the 12 volt OPTOIN- can I use heat shrink wrap over it or wrap it up in electrical tape? Or would that cause it to overheat?

[24c]

You're only trying to get it too run and to be honest, a few jumpers and a bit of wire twisted round a resistor will do. AFAIK, there isn't much current flowing through the resistor, it'll be mA not A with my equally limited knowledge, so I think the chance of your level of heat build up is zilch.

Just do it...it could have been running by now!

[EWflyer]

Just do it...it could have been running by now!

That's true, but the bike is in my garage in Spokane Washington, and right now I'm sitting in a hotel room in Southern California. I'm a captain at Southwest Airlines, and unfortnately I'm a low-seniority captain which means I end up flying on all the holidays (today is our Thanksgiving). Later today I'll be flying from Southern Cal to Las Vegas, then on to Pittsburgh. I've been on this trip since Tuesday morning and it finishes up back in Oakland California on Friday night after flying Pittsburgh to Chicago to San Diego to Oakland.

My next chance to work on the bike will be Saturday afternoon.

[24c]

Well Happy Thanksgiving to you, and all you other Stateside dudes. Look forward to hearing that bike is running...enjoy your hotel room.