Upside down injector pulse widths?

[DouglasVB]

Hello everyone,

I'm working on a Honda Pacific Coast fuel injection project. I have one injector per cylinder setup with throttle body injection. I'm using a MicroSquirt from circa 2011. I've got the bike up and idling without too much trouble. I am having trouble understanding how the VE table and injector pulse widths work with respect to how much fuel is delivered. When I decrease

However, the AFR reading on my wideband O2 sensor shows that I'm around 10.3-10.5. When I decrease the number in the VE table box, the pulse width on the TunerStudio dashboard goes down but the bike's engine speeds up. The AFR remains unchanged. This is at idle with the throttle closed. Is that the correct way that everything is supposed to work?

Sorry for the ignorant question. This is the first time I've done any tuning

Thanks!

Douglas

[24c]

When I decrease the number in the VE table box, the pulse width on the TunerStudio dashboard goes down but the bike's engine speeds up.

OK, Douglas, so ignoring the "not decreasing" AFR for a minute, the engine is running weaker and closer to stoich by your changes, so for your given ignition timing the combustion is better, so the engine revs higher. Can't you slow down the idle a little bit on the throttle stop, reach your desired idle rpm, and move on. Also what is happening to the MAP, whilst this is happening?

Mike

[24c]

Actually Douglas, some of this is in the "manual"

All you need to do is watch your MAP (get it as low as possible) and tweak the VE values, when you have a warm idle. The manual mentions the revs might rise, and you'll have to tweak the throttle stop.
Try and remember that as you reduce your idle VE table, the cold start, warm up routine and after start will be altered too, so you might find it harder to get the engine to fire on a cold start tomorrow
I found it easier to remember the VE numbers before and after, but you could save the old tune, and then create a new one with your tweaked idle settings...that way you can always revert back.
This is something that is easy to forget in the euphoria of your project/baby coming alive and everything's wonderful when it's going right, but a few wrong moves and folks get well confused.

Mike