Ref Sync Capture Analysis

[stevesingo]

I am in the process of fitting M800 to a BMW S14 engine. The Sync (mag) hardware is off a S38 (M5) so is pretty much fixed. The Ref is also from a S38 but I have to make a custom bracket for the sensor. The ref wheel is 8 tooth.

I made a temporary mount to gauge the correct position for the Ref sensor. This is what I got...





The Diagnostics tell me the Sync is OK, but is there any tweaking in advancing or retarding the ref sensor to improve the result?

Any comments...

Steve (A hobbyist, not a pro)

[stevesingo]

Does no one have any comment on this. If not I will assume that all is correct.

Further to this, what is the maximum voltage the M800 can tolerate from a mag sensor? If I am getting 2v at cranking, I am expecting significantly more at 8000rpm!

What can I do to limit the voltage? Resister?

Steve

[MarkMc]

Hi Steve,
You should be using the rising edge of the ref sensor and falling edge of the sync to be correct. The alignment between the ref and sync looks fine as long as they do not change at higher RPM. You can keep an eye on the Sync Relative Position channel, as long as it stays between 20 and 80 it should be fine, 30 to 70 would be better and a constant 50% would be perfect but not realistically achievable.

The ECU will clip the input voltages at 9.8v half wave. There should be no problems with this setup but at higher RPM if you have problems you can increase the air gap to the ref or sync sensors. Roughly double the air gap is half the signal...roughtly, it's not a linear thing.

[stevesingo]

Mark,

Thanks for the input.

Steve

[stevesingo]

Now I have had the time to finish this off I now have the engine running, but getting some sync and ref errors.

Could someone please explain the following

Error Ref/Sync Runt

Error Ref/Sync Noise Ar

Error Ref/Sync Noise Tr

Also where will I find the Sync Relative Position Channel as refereed to by MarkMc? Is the the SyncPos% on the thirrd line of the trigger panel in the show sensor screen.

I will post up a running sync capture tomorrow if required

Thanks

Steve

[stevesingo]

I have just watched the relevant Webinar and I have my answers.

Any comment still welcomed.

Steve

[MarkMc]

Always check to see if the errors are just as the crank starts to turn, you often get some errors in the first half a turn or so....these tend to stress people unnecessarily. Hit enter as the errors come up and see which ones come back. Those are just warnings anyway so will not stop the car running. Hopefully my webinar gave you plenty of info to go on.

[stevesingo]

Engine runs fine now. I changed the position of the sync sensor tooth to get better separation of the trigger edges.

I still have a sync runt warning, so I will look in to that.

Mark, the Webinars were most helpful, but where will I find the Sync Relative Position Channel as refereed to in a previous post. Is the the SyncPos% on the thirrd line of the trigger panel in the show sensor screen.

Thanks

Steve