Hondata

Hi,

i've been datalogging few rides today, just to make sure that A/F is good hence no leaks in exhaust (i thought they could be due to some mechanical issues).

However, i noticed something very strange was going with Cam advance, it was completely incorrect, i can even say - chaotic.
That happened on WOT, VTEC spool on, see the datalog in attachment, starting from 2:05

p.s. i have VTC gear 50 degrees from RSX-S. never seen such a behavior, all and every datalog of my car showed that cam and cam_cmd were identical (+- 1 degree actual from commanded).
p.p.s. the car is Accord Euro CL9 (same as TSX in US), it was warmed up for 10 minutes before i started WOT. ambient temp = 9 degrees C

What is going on??

my thoughts were quite rushing so i forgot to mention some details:

oil level is at LOW mark, will add some shortly and re-run.
i waz using v.1.2.8, now upgraded to 1.3.7 beta and will try on this.
i have Toda C cams and my cal is limited to 40 deg on hi cam, the above run pushed cam to 47-48 deg hence it quickly got 29 knocks where 35-38 deg was commanded.

You cannot use the ECU to limit cam advance - it MUST have a mechanical stop. We do stress this.

VTC operation looks find apart from the one spot at 2:05

I do not believe that it is the ECU - I would look at the oil pressure, VTC, cams & VTC solenoid. I have had problems with the solenoids & VTC mechanisms in the past.

added oil (mid between low and hi marks), fired few more runs, VTC operations appear to be smooth, no chaotic advances/retards detected.

The only thing i noticed that real advance is always a bit late from commanded degree, this happens when my VTC should rapidly move from 10 to 40 degrees, in a short range of rpms.

i tend to believe this is normal behavior in the case?

You would be correct.

According to somewhere, it takes 0.1 seconds for the cam to advance 10 degrees. Keep that in mind, especially when rotating 30 degrees.