Hondata

Have you discussed this issue with your tuner? Is the tach in the vehicle jumping in the same way?

I'm tuner and I have this trouble with new version of Virtual Dyno. In Flash Pro log's no problem, rpm curve smooth.

This erratic line of RPM you can see only in big zoom in Smanager. Tacho is ok ...

I have a problem with bad RPM curve in S300 datalogs. It isn't smooth and erratic.
I have a problem when loading datalog to Virtual Dyno.

Engine work fine, good ground, good distributor, new cap, wires, plugs, plug gap. I don't think that is misfires.

https://a-a.d-cd.net/cb1ef6s-960.jpg
It's ...

I know about Ignition Compensations.

I tell about other thing.

If i put in ignition table value 40* - engine will be work at 40* ignition advance ??? (If all ignition compensations will be 0)

How Hondata calculate ignition advance ?
For example:
Base timing 16*
Value in ignition table at idle 20*
Value in ignition table at WOT at 7000rpm 28*

How much ignition advance will be in the engine ???

I retuned engine with right lag times and injector size, all Ok.
Engine had smooth idle, good cold start and good work.

But old tuner told me, that injector size, dead times and fuel pressure does not matter for engine tuning, because hondata have same calculation coefficient for all injectors ...

I built D16 Turbo, Vitara + Eagles, GT2871, Siemens Deka 830cc injectors and goes to dyno tune.
I had low power goal 275 Hp at 20 psi with 8.2 CR and misfire problem at WOT. Ignition system is OK, sparks BKR8E, new oem wires, new distributor cap.
Next day i had problem with start and idle on cold ...