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I am new to modern ecu and tuning practices. I am using tuner studio to try and tune a yoshifab dsm cas 24t wheel. I have confirmed spark and am timed at 10degrees btdc with tooth #1angle set at 20deg. Car will not run, it coughs and sputters and feels like it wants to start. In all my readings I am under the impression I am off by 360deg, and should be able to add 360deg to my #1 tooth angle to get my timing corrected. However when I add 360 I lose all spark signal. I can’t figure out what I’m missing.

You might be firing correct only on cylinder #1. Confirm the wiring is connected in the firing order, InjA - Cyl1, InjB - Next cylinder to fire.

Same with the Ignition coils, and the Ignition Options/Wheel Decoder -> Number of coils is set correctly.

If it's on full sequential and 360 out, it won't start but merely backfire out the exhaust.

You did confirm the ECU TDC is actually aligned with the engine's physical TDC? This is a common error. There should be a proceedure in the ECU directions for setting this, usually locking the advance at 0 degrees, then cranking over (good idea to fully charge the battery to get the most speed out of it) with the plugs out and a timing light connected to align the flash to the TDC at the front pulley, if it's not aligned, change the offset to suit.

As David said, it may be an issue with in-correctly matching the ignition and/or injection to the relevant cylinders, again an easy mistake to make.

Spark plugs can give useful information, do they all look the same or are they different with, say, one having a dry lightly sooty insulator, or a white shiny appearance from un-burned fuel, maybe a wet and black appearance?

If they're all wet and black it suggests a very rich mixture.

Oh, on that, a rich mixture will tend to give a more muffled misfire, and a lean one a much sharper 'crack' sound.

Since you mentioned it's a DSM, is it operating wasted spark still?

I ask because if so, the 360 out possibility goes away.

Have you confirmed engine speed is stable and reasonable during cranking?

Have you confirmed there are no timing errors?

That reminds me, Mike, I forgot to ask if it was a running engine that's been converted, or a rebuilt engine that the OP has fitted the ECU to and is trying to get started.

If the latter, it could also be a mechanical issue with camshaft(s) timing, or other issues.

Thanks everyone for getting back to me. I’m going to start with confirming again that I have the engine base timing good and cams aligned properly. This will be the second time but in frustration and anger could have easily over thought or under thought. Probably the latter. Thanks again.

Make sure that you are actually on the compression stroke at TDC of cyl #1 when matching the timing. It's very easy to get this 180* out, because the piston is at TDC twice in the cycle. This is the most common issue I see.

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