This Suzuki 4cyl 1.6L (high-compression, NA firing order: 1342) engine had factory trigger originally


TDC marked on the 36-2-2-2 MM13M16 wheel:



I was called to review an engine that has "factory suzuki trigger", and is almost impossible to start.

I thought some configuration tweak would be needed. It turned out the installer instructed the mechanical crew to GRIND OFF teeth from the factory wheel and convert it to 12-2 (see above pic, "crippled wheel").

I started by capturing triggerlog. It became obvious from triggerlog that

When cranking with fuel and spark, the missing tooth disappeared completely. Something like 110..120 % but clearly not 150..200% or more (remember the N-2 missing tooth is theoretically 300% of prev tooth).

What could be done with such a crippled primtrig wheel ?

When no missing tooth is detected at the proper position (because of significant angular acceleration after TDC and combustion, during cranking) The firmware shuts down the inj/ign train (as it should). Perhaps not impossible to have some "10 tooth" special case to ignore such problem from crippled pattern at startup, but we don't like special cases too much (just for one broken install: but most likely there are half dozen from same installer, I suspect).

Griding further (after planning!) could be a solution also:

4-1 Path


6-2 Path


Factory 36-2-2-2 was put back in

Captured without sparkplugs, and trigger_tooth=0 and TDCdelay=70 :


Since we cannot advance 65 deg, we delayed 115 degrees and got the good results (see above).

From Bench, the MM13M16 pattern:


This triggerlog was captured earlier during a benchtest of Suzuki_36_2_2_2_No_Camsync configlet (configlet has been updated with correct settings for 1.2.27 and up during testing), and recently the triggertooth=4 applied also...

Although this engine has camshaft sensor removed as said above, ...

For the curious, Suzuki 36_2_2_2 with stock camsync also tested an verified good (also from bench: