MoTeC Global Forum

4 stroke 36-2 ref (crank) no sync i have 4 coils running wasted spark
And 8 injectors
Ref sync mode is 81
Injector operation is set to 0 ( should it be set to 1 )
Im bit confused about what happens to the 8 injectors running non sequential (does it run semi sequential)?
does the injector ballance table still operate ?

I no it would be best to set up a sync but for now i would like to try setting up without

Ref/sync mode should be 71-74. With no sync sensor a "cycle" will be one rev, therefore you have 2 missing teeth once/cycle. Is this a 4 or 8 cylinder? If the engine is 8 cylinder you will need to set the number of cylinders to "48", if its a 4 cylinder then set to "24". I think injector mode can be left at "0" but the injectors will be fired in pairs (some would call this semi-sequential).

What do you mean by "injector balance table" - do you mean individual cylinder trims (no wont work without sync) or do you mean secondary balance table (yes will work)...

Thanks for reply sorry i mean sec ballance table
And yes a 4 cylinder

Was worried injector 1/4 an 5/8 would trigger together

So evry 360 degree i will be seeing 2 missing teeth
By setting to 71-74

And by setting to 24 cylinders what is happening at each tooth event with the mode on 71-74

From what ive read it seems choosing cylinders 24
Mode 71-74 would make the first 360 deg a coil fire cylinder 1and4 and on the next 360 deg cylinder 2and3
So after the crip has been set the ecu is just looking for the missing teeth as refrence
Mode 71-74 on help screen saying requires sync sensor ?
Would it thorw up an error ?

imi wrote:From what ive read it seems choosing cylinders 24
Mode 71-74 would make the first 360 deg a coil fire cylinder 1and4 and on the next 360 deg cylinder 2and3

No, with no sync sensor you only have a 360deg "cycle". Ign output 1 (cyl 1&4) will fire at 0deg, ign output 2 (cyl 2&3) will fire at 180deg, in another 180deg you are back at 0 so the same cycle repeats.

So after the crip has been set the ecu is just looking for the missing teeth as refrence

Yes the first tooth after the gap is what motec calls the index tooth. Hence the term Crip = crank index position.

Mode 71-74 on help screen saying requires sync sensor ?
Would it thorw up an error ?

The help is not quite correct there - with number of cylinders set to "24", "48", "36" or "612", the sync sensor is not needed for modes 7X.
Im not sure if the ecu will still record a sync error but everything will run fine.