syncrelpos on M4 Pro

[lloydie]

Hello all,
Up until a few days ago i was using group fire to fire my injectors and all was well.
Managed to get sequential injection up and running yesterday (it needed a bigger adjustment of IJPU than i was expecting) using the stock cam sensor on the exahust cam of my Mazda BP engine which is a Hall effect combined ref&sync. The car runs OK, a little rough at idle, but most importantly with no diag errors and 'Sync OK' against the sync status.
The odd thing is that when i log the data to see the syncrelpos%, to see how much it changes at high rpm, the syncrelpos is at -1% for the entire duration of the log, regardless of RPM. Im using the Motec supplied ref/sync mode no. 162 - does synrelpos only display if you're using your own custom ref/sync ?
Thanks

[NathanS]

Hello Lloydie,

The -1 in your logging for the RelSyncPos channel means that it is not calculated for the Ref/Sync Mode you are using.
The RelSyncPos channel is generally only calculated for multi-tooth and missing/additional tooth modes as there is not a defined relationship between the crank and cam signals i.e. there is only one tooth on the cam which can occur almost anywhere within the engine cycle and as such its positioning can be optimised, whereas for OEM modes specific pattern relationships are expected which can not be changed.

[lloydie]

Thank Nathan, its as i expected. I was only interested because ive seen evidence that suggests the stock hall arrangement can become erratic at high rpm and i just wanted to see it for myself. It makes sense that its not supported as the relationship should always remain constant..