Stutter at 100% TPS and ~5000RPM

[MWPau]

Hi all,

I've got an odd miss issue that happens on full throttle at around 5000RPM. It only lasts a fraction of a second.
If i continue accelerating, the problem doesn't happen again.

Its quick enough that it doesn't appear as a dip in RPM in the logs. Everything in the logs look perfect when it happens too.
I do log Lost Sync Count, and its always 0.

Any ideas as to what i should be looking for here?

Thanks

[Matt Cramer]

[MWPau]

Okie dokie.
Its not a simple tune...

[Matt Cramer]

The RPM does look a bit wavy to me, but I'm not seeing any clear cut causes in the ECU. I'd first try a bit more dwell or a tighter spark plug gap, then look into whether this is a mechanical issue with the engine.

[MWPau]

Plug gaps are about 1.1mm from memory. I'll tighten those up a bit.
Maybe these COPs aren't quite as strong as i thought.

Engine appears to run sweet everywhere else, so i can't think what else would cause the problem.

Thanks.

[WillExoIX]

I had a similar issue and I think it boiled down to one of two causes; the MS1 cpu, or the crystal body being soldered directly to the pad on the main board which is a nono.

[MWPau]

Fixed.
I increased dwell from 2.1ms to 2.9ms, and increased the spark time from 0.7ms to 1.0ms.