AVCS VVT angle out of sync diagnosis MY07 GT B

by **cynner** » Tue Aug 27, 2013 9:50 pm

The ECUdataScan stuffed up when I tried to log the recalibration (couldn't write to the SD card)

So only logged later on after removing the SD card

by **cynner** » Thu Aug 29, 2013 10:18 pm

Got a log from a good car (Paggaz) and it looks fairly similar to mine. One of the OCV's is sometimes slightly behind the other, and it also has that "saw tooth" look in certain spots.

I'm wondering if maybe it's normal for there to be the occasional slight variation between the left and right hand sides...

: paggaz.png (53.29 KiB) Viewed 3874 times

by **paggaz** » Thu Aug 29, 2013 10:23 pm

Looks much better in graph form than that raw data!
Interested to see what others think about it.

by **KiDo_Tuning** » Thu Aug 29, 2013 10:30 pm

Looking good. The one to look out for is the OCV oscillating trying to constantly correct

by **cynner** » Thu Aug 29, 2013 10:45 pm

Pulling my OCV out, giving it a good dose of carby cleaner and wd40, and running some Magnetic diesel engine oil seems to have stopped mine oscillating. Probably wont bother getting new OCV's any more?

EDIT: Dammit, this morning more oscillating. Cleaning helped only for a few days. Have ordered new OCVs.

by **bigBADbenny** » Thu Aug 29, 2013 10:59 pm

Diagnosing the issue can be done with a variation of the factory diagnostic procedures:

With the car parked, in any gear, clutch in, logging 30 sec or a minute holding 1500, 2000, 3000 rpm.

Secondly to log whilst cruising at 100 kph on the freeway in 4th, 5th and 6th.

The primary symptom is an obvious oscillation of one of the VVT angles at 1500 rpm static test or lower rpms/higher gears in cruise.
The secondary symptom is lag between VVT angles.
And lastly a difference between maximum VVT angles achieved.
If one VVT angle is locked or sticks open or closed, the avcs intake cam gear itself may be damaged or blocked with foreign matter requiring replacement.

The primary cause is a weakening of the OCV's ability to operate fully, either due to low oil levels, oil clogging, jamming with foreign matter or possibly even from lack of proper shielding of the wiring and of the OCV itself.

As such, solutions range from topping up oil, oil flushing, removal and cleaning (including activating with a 9v battery) and ultimately replacement of the stock item.

by **cynner** » Sun Sep 01, 2013 2:56 pm

This mornings project was removing both OCV's, cleaning both (including actuating with 9v battery), swapping left and right side OCV's, and resetting ECU. Got a 9v battery plug and alligator clips from Jaycar for about $3, made it easy.

It's helped a little - both OCV's are a little better matched in the logs, and I've confirmed the RH one was a bit dodgy as now the left-hand-side (former right OCV) has the slight lag the that right side did. New OCV's are currently in transit anyway...

I found the left (passenger) side much harder to remove... had to remove the air pump thing, oil filler spout, etc. Lots of bolts that were fiddly to get to. Not looking forward to having to do it all over again in a couple of weeks

Kim

by **bigBADbenny** » Sun Sep 01, 2013 5:46 pm

Just the removing the battery, oil filler and unplugging the loom that crosses that area was enough for me

Any foreign matter or sludge evident in the OCV's ?

by **cynner** » Sun Sep 01, 2013 5:59 pm

Nah OCV's looked quite clean... no sludge or anything in there.

by **KiDo_Tuning** » Sun Sep 01, 2013 7:47 pm

cynner wrote:Nah OCV's looked quite clean... no sludge or anything in there.

Just like a wastegate solenoid, the OCV have a resonant electrical frequency. Being on the drivers side of the car, the OCV is exposed to a sine wave that gradually alters the magnetic field inside the OCV

I have theory to simplify diagnostics... the wiring looms have a part number tag usually on the plug that connects to the firewall on passenger side of engine bay. I think the people with the issue are going to have the same part numbers

by **cynner** » Sun Sep 01, 2013 9:03 pm

Has anyone here replaced their OCVs only to find the drivers side one starts to fail again after a while? (is it worth replacing the wiring loom too?)

by **bigBADbenny** » Mon Sep 02, 2013 12:27 am

I've seen recurrence reported on the USA forums. A possible solution is swapping sides annually if Matts theory is correct.
Ill be sure to note that plug tag

by **cynner** » Mon Sep 02, 2013 9:59 am

Wonder if there is a way to eliminate or reduce the resonant frequency on the earth current?

by **bigBADbenny** » Mon Sep 02, 2013 11:56 am

Its just a theory at the moment.

Oil:
IIRC the (RHD) drivers side OCV gets the oil after its been through the passenger side OCV.
It could very well be oil cleanliness or oil pressure related.

Interference, gaussing, electrical:
Extra shielding or grounding could be added to the area of the OCV, its wiring or between it and e.g. and the adjacent injector.

by **cynner** » Mon Sep 02, 2013 12:06 pm

Wrap OCV in foil. Solved :wink:

AVCS VVT angle out of sync diagnosis MY07 GT B

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Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

Re: AVCS VVT angle out of sync diagnosis MY07 GT B

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Re: AVCS VVT angle out of sync diagnosis MY07 GT B

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