Points Ignition Wiring with Microsquirt

[1979-mini]

I cannot find any information on how to wire up a point system with microsquirt. The only thing I found was with the mS-II. It refers to DB37 Pin #24. Is there a wiring diagram specific to microsquirt anywhere?

http://www.megamanual.com/ms2/pickups.htm

Thanks.

[1979-mini]

I guess, it is unclear to me in the wiring diagram for microsquirt whether I will need to use the OPTOIN+/- wires at pins 30 and 31 or the Ignition Outputs at pins 11 and 12.

Thanks.

[newtyres1]

Are you running fuel only, or do you want to control the coil with uS?

Ian.

[1979-mini]

I will be starting with running only the coil with microsquirt. And when that is working well, I will then get my fuel running.

[Matt Cramer]

Ok. In that case, probably the slickest way to handle this is to wire the Optoin+ to a 12 volt source with a small resistor (1K or less) and Optoin- to the points. Then set it to trigger off the rising edge.

The ignition output wires are for firing coils.

[1979-mini]

Ok Matt, thanks for the help.

I was just building part of my wiring harness, and now I know which leads I will need to wire and which ones I don't.

Brian

[1979-mini]

Matt, i've wired up everything including the Pertronix ignition as instructed in your previous responses.

Here's my problem. I crank the motor, and it wants to start but seems to be getting no spark. I know the timing isn't spot on, but I tried so many settings and offsets, I should have hit something at some point.

I got one setting when the motor ran (poorly) for about 10 seconds. But never again.

I think I have one or two problems (1. Spark strength, 2. Initial Timing)
I checked the spark, and I do get spark, but it seems kind of weak in my opinion. What could cause a weak spark?

I am going to try a few things...
1) rewire my coil the conventional way to compare the strength of the sparks with and without MS triggering to see if there is a difference in spark strength
2) If there is a difference, should I change the resistor (I am using 1k right now), to a lower value? Will that increase the spark strength?
3) My Optoin - is grounded (to the body, not the engine....does it matter?) I will wire it directly to engine as a trial too.

All that said, maybe its just not firing at the right time. Since I pulled the dizzy out to disable the advance mechanism, I am not sure where the initial timing is set at now. If I set the engine to TDC, how can I know for sure what the trigger offset needs to be? If I can manually cause the MS to send a spark by rotating the dizzy in the block, I can figure out the offset. But I noticed that the coil doesn't heat up when I turn the key on. Does the coil primary only come alive when MS sends voltage to it?

Sorry about the long post.

[Matt Cramer]

The resistor is for the RPM signal into the Microsquirt and does not affect the strength of the spark output. The dwell settings, however, do change the strength of the spark. However, too much dwell can damage the VB921s; you may want to take it out of the case and make sure the VB921s aren't getting hot when you set the dwell.