Sync Long Tooth Gap, appeared and disappeared?

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rac
Posts: 13
Joined: Tue Aug 14, 2018 5:06 am

Sync Long Tooth Gap, appeared and disappeared?

Post by rac » Thu Aug 30, 2018 3:31 am

New Syvecs user here with a N54 PNP kit. Had a Sync issue this morning which left me stranded for a while and wondering what I should be looking at to determine the source of error.

Car has been running for 5 days or so, initially on a base file sent from Syvecs and I’ve been in the process of making fuelling revisions to subsequent programs without any significant issues I couldn’t easily correct. However this morning after making some additional injection time changes I ended up with a SYNC issue. I went ultra-lean shortly after driving off from a reprogram (however I had been idling with these changes made for maybe 10mins ok) and then the car shut down. I could not restart the car with any previous Cal file I had, even with the original base file all of which had been running fine.

The previous start which was ok showed:

SYNC: 0->TURN
SYNC: TURN->360
MODE: STOP->CRANK
SYNC: 360->720
MODE: CRANK->RUN

The failed start after my issue was:

SYNC: 0->TURN
SYNC: TURN->360
MODE: STOP->CRANK
SYNC: 360->720
MODE: CRANK->RUN
MODE: RUN-> CRANK
SYNC: 720->0 (LONG TOOTH GAP)
SYNC: 0->TURN
MODE: CRANK->STOP
SYNC: TURN->360
MODE: STOP->CRANK
SYNC: 360->0 (LONG TOOTH GAP)
MODE: CRANK->STOP
SYNC: 0->TURN
SYNC: TURN->0

So I was thinking a wire has come loose but then about 10mins later I tried to start the car as a last attempt and it did all OK again – I hadn’t made any changes at all.
Where is the best place to start diagnosing what might have happened here?

Thanks.

rac
Posts: 13
Joined: Tue Aug 14, 2018 5:06 am

Re: Sync Long Tooth Gap, appeared and disappeared?

Post by rac » Thu Aug 30, 2018 8:59 am

Additionally looking at lambda just prior to the event, appears it went lean abnormally while fuel was still being delivered and then increased while in closed loop. So the sync issue might have come about from that as it was thrown as the engine died?

stevieturbo
Posts: 835
Joined: Sun Dec 07, 2008 2:04 pm

Re: Sync Long Tooth Gap, appeared and disappeared?

Post by stevieturbo » Thu Aug 30, 2018 7:32 pm

Check the syncscope to see what the triggers are like and then check any voltage and trigger thresholds for crank/cam sensors

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