Composite Log - Deciphering data-Crank/Cam signals

[1uzfevolvo]

For a while now I've experienced a loss of sync at around 1700rpm, in any gear, mainly during warm up, but it can appear out of the blue at other times, and it can be whilst accelerating or decelerating. Catching this elusive act on a data log has been difficult but today I was successful. Twice.

Trouble is, now I have the data, I'm not sure what it is telling me.

In the composite log attached, on page 31 of 36, there are two episodes where the cam signals are close together then there are the loss of syncs episodes shown in red. What does this suggest? I have also attached a data log of a separate event later on in the drive. Motor and tune behave pretty well in every other regards and the motor happily idles and revs cleanly and quickly.

Motor is 1UZFE, CoP, crank and cam VR sensors. What do I need to do to get rid of the problem.

[Matt Cramer]

The composite log shows an extra tooth on the crank signal. See the arrow in this picture. If you are using a V3.0 or V3.57 main board, try adjusting the pots for less sensitivity.

[1uzfevolvo]

Thanks. I could see the extra tooth but wasn't sure how to get rid of it. I'd thought if the sensitivity was the issue the the problem would be there all the time.

Will get the tools out.

[1uzfevolvo]

Taken me a while to look at this issue but I went back to the start and zero'd the R52 and R56 pots. From there, I adjusted until I had the motor running and revving. One last miss at 1700rpm and a further adjustment to R52, I've enjoyed driving with no loss of sync for a couple of days now.

Interestingly, the pots are adjusted to exactly R52 4.5 turns clockwise, R56 2 turns clockwise, pretty close to where it was originally.

What has me intrigued is that with VR sensors, all the manuals say having the pots full anti-clockwise but at this I cannot get the car started.

Would Rising Edge Vs Falling Edge effect this. I'm guessing also there's always some uniqueness to each cars settings.