How Retarded can a NB intake cam be for decoding to work?
 

I have a tendency to complicate my problems a bit...
My startup problems can be mechanical (cam timing etc) or sensor/sync/Decoding. Lets focus on the decoding here.

As I see it from the Composit Log the Cam signals fall within the window of the crank signal so it "should" be ok, but can there be a problem if it's too close (3ms in some cases) ?
https://www.miataturbo.net/attachmen...ing-issues-png

Advancing the cam one tooth as a test will be tomorrows exercise (if I can find some energy).

I have never heard of there being a problem so long as both of the cam pulses on the double-side fall with the gap between the nearest two crank pulses.

I have never proven this empirically, so this is just speculation and the result of having not heard anyone complaining.

I assume that everything runs fine after the engine is started? No sync errors, misfires, etc?

No start at all, only spitting misfires and during cranking at WOT real backfires (drops revs to zero if the battery isn't fully charged).
TS reports mostly sync, but also no-sync sometimes during the same cranking.

Ok, I don't know the history here.

From your description of the behavior while trying to start, it almost sounds like the 1/4 and 2/3 ignition channels are swapped. I've done this myself a number of times. (eg: comparable to having the plug wires on the wrong cylinders.)

If you haven't already, use a timing light to look at the spark advance while cranking. It helps if you paint a big white splotch on the pulley with white paint around the area of the notch, so you can find it if it's not where it's supposed to be.

I wonder if, having done this test, you'll find it to be 180 degrees opposite what it should be.

It's hard to do while on your own (cranking and operating a timing light) and all the wiring is exactly the same as when the engine ran last time (different length harnesses to the coils just to prevent these mistakes).
Is there any way the 1/4 and 2/3 can be swapped in software (I would not be surprised if the settings changed while the MS have been on the shelf)?

I'll see if I can find some friend to help me with a timing light tomorrow.

Hmm, can the coil channel swapping be tested by a radical fixed advance (190 instead of 10)?

I'm not sure if this was covered in one of your other threads, but on this new engine, did you mess with the crank pulley?

The stock four-tooth crank wheel must go on facing the proper direction. On the stock ECU, improper installation results in a no-start (I believe). Maybe that's causing issues for the MS as well.

Not really, you just need a remote starter switch, cheaply sold at all auto parts stores. It is connected between the two terminals of the starter, and is also handy for compression testing. This is the specific one I use: 12 Volt Remote Starter Switch

Hmmm...

On the MS1, quite easily. In fact, DIY's default MSQ for the MS1 has the outputs reversed, and they correct this by flipping the wiring to match. (On a DIY-style MS1 configured for a Miata, IG-B goes to 1/4, and IG-A goes to 2/3.)

On the MS2 & 3, I don't think you could, particularly when configured for an NB.

This is highly improbable. Configurations stored in EEPROM are as close to non-volatile as you can get.


It's possible I may be leading you down the wrong path here. I would still advise doing the test with the timing light and the white paint, but I'm less certain of it now than before.

To be able to test with a timing light, it's easier if there is spark on no1...
Changed the 1-4 coil (I had one new) and there was spark, exactly where it should be (between 0-10 degrees advanced). The 4 tooth of the indicator wheel is also in the correct place, compared to numerous pictures and two working NB engines.

Now my hope is that the fouled plugs just needs changing and a newly charged battery.
I can't think of anything else now (except advancing the cam one tooth as a last resort).

Oh well, it can be held running, on three cylinders...
It took some serious cranking at WOT to get it sputtering well enough to start firing.

Not only was one coil bad/poor the lead to no3 seems to be non functioning (placed the new coil on 2/3 and I assume that the outputs are straight connections in the coil). The three other plugs get sooted while the 3 is clean and wet.

I have an old lead that will be tried tomorrow.

With this setup, I might need to learn something else than Speeddensity/MAP. keeping it running at 2000rpm showed about 70kPa. How that wil change when I get it running on all four I don't know.
Time to read up on Alpha-N tuning (unless it's just changing and autoTuning with the same AFR table).

So everything is OK, just the basic stuff of getting spark at all was missing.
Did I mention that I overcomplicate things...:facepalm:

I forgot to add the solution here as well (a build thread is long overdue).
One lash cap had decided to place itself of the side, meaning no compression on no3...

So now I know how to analyze that and fix it in field like conditions, learning from your own mistakes beats reading about it.

Engine is now broken in using alpha-N, oil cooler added and the second oil change is made (first was full of gas, and second was greyish from break in, so all is according to plan).
Next on the agenda is to connect the OCV to test if the VVTuner can hold the cam advance at set level with stronger springs (beyond 37 degrees I have contact).
The cams start to pull around 5000rpm now (buttometer and ear) , some advance might move that 1000rpm earlier (that's the dream).