DIYAutotune featurespotlight question "Half Sync"

[arran]

Hi all,

A couple of weeks ago this was posted to the DIY Atotune facebook page:

Time for another #featurespotlight - MS2/Extra and MS3 have a half sync mode with many wheel decoders for rapid startup. The MegaSquirt can start up in batch fire and wasted spark and run this way until it syncs up with the cam sensor. This lets you start up faster because the engine does not have to make two complete crank revolutions for the ECU to sync up. This works with many common trigger wheels, including 36-1, 60-2, and LS1 - basically, any design that can be run in wasted spark off the crank trigger alone

It sounded like a cool thing but I could not remember seeing it anywhere. I'm running MS3 with 1.3.2a firmware. The old and the new documentation don't mention half sync. I asked a question on the FB page a week or so ago about how to find it without yet receiving a response. Is this something I am just not seeing or is it in 1.3.3 beta or 1.4 beta?

Thanks

[grom_e30]

what are the trigger wheels are on your crank and camshaft, that firmware version should do it on its own with the correct wheels.

[jsmcortina]

Half sync is mentioned.
See http://www.msextra.com/doc/pdf/html/Meg ... 3-288.html

James

[mr_minnis]

I was wanting to mess with this setting also. Of coarse my engine is apart, lol.

The only thing I found was under cranking/startup was "Batch fire during crank". I am using ms3x with FW 1.3.3 beta 5 and TS 2.6.04. I think that has to be it. However I am not sure.

[grom_e30]

if you have a trigger wheel arrangement that will run in wasted spark and semi sequential off just the crank signal, eg a missing tooth wheel and single on the cam. it will run in semi and wasted spark until the cam signal is detected then it will automatically switch over to full sequential. no settings needed.

[arran]

The wheel is a standard Mazda Rotary FC Nippondenso unit. I think the correct way to describe it is 24/2.
It has two wheels, a 24 tooth wheel and a separate 2 tooth wheel.

That reference to half sync could include a bit more detail James!

I don't think half sync is enabled automatically, the reason I thought this would be cool is that the engine does take a couple of revolutions to get going and it would be nicer to have it fire faster, not essential, just nicer.

I did ask on Facebook if this setting was 'batch fire during cranking", a simple yes or no from DIYAutotune would have been great but the question was just ignored, which is irritating.

I have enabled "batch fire during cranking" to see what it does. The tool tip associated with that setting reads:
Allows fuel to be fired on each tach event in a batch-fire mode on a sequential install. Can be useful in cold climates to allow large cranking fuel flow.

Seems different to the facebook description, copied again:
Time for another #featurespotlight - MS2/Extra and MS3 have a half sync mode with many wheel decoders for rapid startup. The MegaSquirt can start up in batch fire and wasted spark and run this way until it syncs up with the cam sensor. This lets you start up faster because the engine does not have to make two complete crank revolutions for the ECU to sync up. This works with many common trigger wheels, including 36-1, 60-2, and LS1 - basically, any design that can be run in wasted spark off the crank trigger alone.

[jsmcortina]

Half-sync does not apply to "Dual Wheel". The 24/2 pattern requires a cam pulse before it can do anything.

Batch fire during cranking does what the tooltip says.

James

[arran]

Thanks James, appreciate your time