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View Full Version : Please help Strange spike in cyl air



scottcmb
September 13th, 2012, 11:41 PM
Gidday guys.....please help with this problem

In the log attached there is some runs with strange sudden spikes where the cylinder air drops to zero causing the ecm to to shut fuel off and advance the timing to its commanded timing for that amount of air......looking at the time it has 0 air it lasts for 0.1 seconds then the air comes back to normal.........as you can see it does happen on all runs......and nothing has been altered on the tune for all these runs.

Could it be a problem sensor?.....if so which one?

The engine is an LS3

Tune is currently running mafless 13900

Cheers Scotty

GMPX
September 14th, 2012, 09:42 AM
Check the MAP_SQ column in B8001, if the whole thing is not zeroed that could be the issue.
If it's not, just select the entire VVE, add 1 (so everything is changed) and EFILive will recalculate the VVE with that column automatically zeroed.