Miata Turbo Forum - Boost cars, acquire cats. - Getting unintentional rev limit?

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Getting unintentional rev limit?

Alright I watched the start up videos. They were great! WB works, and it's matching what the gauge says so that's great. Calibrated sensors, and worked on the idle. Idle is pretty solid now. Startup is still a work in progress. Warm start up seems to struggle to have that initial climb - will work through the WUE duty cycle later after I work out the idle VE cells. So the main question...

Started doing 2nd gear pulls. Basemap VE tables gets me ~11.5 at 4500rpms and down to 10.6 at 6500. The weird thing is that there's this pretty startling fuel cutoff - jolt that occurs at ~6500 rpm.

Took the WOT section and reduced the cells together a few bits. The same region went up to 12.6 - 11.8. Great! But then...the same thing happened again at ~6500 rpm. So I immediately let off the gas.

Reduced the cells some more - more in certain zones than others. And now the region is 12.8 - 12.6 AFR. Better! Same thing again happened at ~6500 rpm.

Rev limit is set to 7000 rpms (basemap), with soft limit zone 200 below (didn't touch any settings in this area). Thoughts?

I've attached datalogs.

Oh...huh, wow. So this is a cable issue? Also, would that mean if I wasn't connected to a laptop, I wouldn't experience this?

Laptop only reads the MS, it has nothing to do with running the car. Sync refers to then ecu knowing where the engine is to sync the rotation to the ignition and injection.

Oh I see. That makes more sense. So I guess the question would be...what's causing me to lose sync? Or...what should my next steps be?

I cannot give you the final answer, but the next step will be to tell us MS model and who built it. Some have opto isolators in the Cam and Crank inputs, and some have circuits with trim pots.

MSPNP2 built 2018 - newest firmware.

REQ...basemap assumes 238cc/min nb1 injectors (so presumably @ 43.5psi). When I purchased my cleaned/tested nb2 injectors - they were said to flow 282cc/min at 43.5 psi. I'm guessing this is why the basemap was running so rich. The alleged path would be...

Change from 238 REQ = 12.7
to... 282 REQ = 10.7

Multiply basemap VE table by 10.7/12.7 = 0.84?

Interesting... my "adjusted map" is closer to this map now...does anyone know the deadtime for NB2 injectors? Using the basemaps's 1.3ms.

Just wanted to leave a closing note for anyone who finds this thread... problem solved. The crack position sensor found its way loose pieeee something over the years. It was spaced ~2.5mm. Moved it back to 0.5mm, no more sync loss.