Incorrect Cam advance vs Cam cmd!!

FlashPro questions & answers specific to the 2007-2008 US TSX
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core58
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Joined: Mon Jan 09, 2012 2:35 pm

Incorrect Cam advance vs Cam cmd!!

Post by core58 » Thu Oct 18, 2012 3:06 am

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??
Attachments
datalog0000_incorrect_cam.fpdl
wrong CAM from 2:05 !!
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core58
Posts: 20
Joined: Mon Jan 09, 2012 2:35 pm

Re: Incorrect Cam advance vs Cam cmd!!

Post by core58 » Thu Oct 18, 2012 3:58 am

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.

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Hondata
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Re: Incorrect Cam advance vs Cam cmd!!

Post by Hondata » Thu Oct 18, 2012 8:26 am

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.
Hondata

core58
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Joined: Mon Jan 09, 2012 2:35 pm

Re: Incorrect Cam advance vs Cam cmd!!

Post by core58 » Fri Oct 19, 2012 10:20 am

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?

Anjuna
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Re: Incorrect Cam advance vs Cam cmd!!

Post by Anjuna » Mon Oct 22, 2012 6:20 pm

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.

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