Upgraded to MS3X. Losing sync on cranking
 

Got everything completed. I didn't switch the spark outputs out of laziness and just went ahead and wired fuel and spark through the ms3x. My board now looks like a normal MS2 build, except for IAC1A and IGN wires. I'm still running on the CAS with the cam input going to the MS3X. Pullup jumper for the cam input is installed, and the pots are set fully counter-clockwise, with R11 2 turns clockwise from that point.

I'm losing sync when cranking. Running a map posted by Brain last year to check my settings against. Here's a composite log that doesn't look quite right. Any ideas?
https://www.miataturbo.net/attachmen...ine=1331830217

And the same log, zoomed out so you can see the sync error pattern.
http://i20.photobucket.com/albums/b2...ogunzoomed.jpg

your crank and cam are not on the same polarity.

what input method are you using for each?

It sounds like you still have crank going through the opto circuit like a typical MSII build and the Cam input into the MS3X. Is that correct?

if so, you'll need to mod it slightly.

I wired for whichever method this picture would signify.
https://www.miataturbo.net/attachmen...ine=1331832086


Alright then. To fix this, I need to remove the green wire and jumper. Then jump put jumpers in D1 and D2, between XG1 and XG2, and jump Tachselect to optoin, correct?

okay. so:

Remove the green jumper from Tachselect to XG1
Remove the two red wires (should already be gone-thats the cam input)
remove the Purple jumper

Jump D1
Jump D2.
Jump XG2 and XG1
Jump Tachselect to Optoin
Add a pull-up like the yellow line shown in the image below:
https://www.miataturbo.net/attachmen...ine=1331832768


that should fix it. make sure your set to falling edge trigger capture. This will use the same input method (opto circuit) but reverese to polarity to match that of the cam signal.

Do not wire per Scott's directions.

Wire per the directions in the manual, using VR + Pullup for the CKP signal.

From: http://www.msextra.com/doc/ms3/ignition.html#vr

V3.0 board - VR Input + pullup
a) Solder a link between VRIN and TACHSELECT
b) Solder a wire between VrOUT and TSEL
c) Install a 1k resistor (any value 470R - 2k2 is likely ok) in the proto area. Connect one end to the 5V hole and join the other end to VRIN with a jumper wire.
d) With a small screwdriver, turn the pots, R52 and R56, about 12 turns to the fully anticlockwise position (you may feel a "click" when the end position is reached, they can't be damaged by turning too far.) and then turn R56 back about 6 turns clockwise.

http://www.msextra.com/doc/ms3/pix/v30vr.png
http://www.msextra.com/doc/ms3/pix/v30vrpull.png

I do not have an R52 or R56 present on the board. I don't think it was clear in this thread, but this board was originally running MS1.

betting he doesnt have that on his board. otherwise that woul dbe the better way.

Going back to the MS1-styled input worked.

Ignore the picture, it was set to rising edge.

What's the reason for the incogruencies between the input methods y'all want me to run? The VR input circuit is the proper circuit, but the opto circuit happens to work, without the adjustment pots?

Actually, its not quite working yet. When set to falling edge, I'm still not getting complete sync.
https://www.miataturbo.net/attachmen...ine=1331839549

When set to rising edge, I get sync, and enough combustion to the point where it will idle on 2 cylinders, though I suppose timing is way off or something bad.
http://i20.photobucket.com/albums/b2...oodcomplog.png

use rising. sorry i told you the wrong one.

Cool. Now on to troubleshoot lack of combustion.