VVT Not Enabled

[DarkPira7e]

Chasing an issue with VVT staying at 0 in my car. Here's what I've done so far-

Checked my clamped vacuum lines on the solenoid under the intake plenum
Checked for vacuum leaks overall
Re-flashed my tune and reset the ECU by removing battery power with all accessories on for 30 minutes
Started car and did not touch gas pedal for 15 minutes
Reverted to first tune revision for car when turbo was installed
Reset ECU the same way I did before
Started car with the car already hot, no gas pedal for 15 min

VVT still will not enable.
One cam in ECUTEK is not cycling until I start driving the car, it is exhaust bank 2.
I replaced the OCV solenoid with a known good one and reset ECU again.

My question also is this: does exhaust bank 2 normally not oscillate with the other 3 cams, or is the actual OCV probably filled with gunk?

This started with sudden loss of power in most of the load map one morning. Idatalogged and found that VVT isn't turning on, which is why the car isn't building boost quick and has 1/4 of it's power in positive boost pressure load areas because there's no timing from VVT.

The picture below shows 3 of the 4 cams oscillating during a cold start cycle, and exhaust bank 2 sitting calmly at 0.



Thank you for any insight. The car has no other trouble other than it runs like shit in most of the load map.

Car is a 2013 FRS running at custom turbo setup. Stock engine, ECUTEK is my tuning platform and I'm using A01C revision since B01C bugs out with Racerom. Car has been turbo and had 63 tune flashes with no issue and 9,000 miles.

[Tonrogs]

I had the same issue and it was a bad cam angle sensor. Not the solenoid, but the actual sensor.

[DarkPira7e]

Originally Posted by Tonrogs

I had the same issue and it was a bad cam angle sensor. Not the solenoid, but the actual sensor.

Thank you! I have a spare, I'll swap it. I've nothing to lose, so why not!

[Ultramaroon]

Until Tonrogs' reply, without codes, I would've never guessed. Awesome insight.

[tomm.brz]

a hint is that vvt exhaust reached negative values
Exhaust cams aren't allowed to go advanced past 0 so that is a false logging, so I also think is the cam angle sensor
Also cheap to buy, but be aware it needs a really careness to install because the distance must be corrected with special gaskets if needed, to have around 1.3mm of distance between the sensor and the cam plate

Otherwise you can induce misfires, there is a TSB explaining very well this

I mean, just install it, but if you get cel and misfire at least you know why

[DarkPira7e]

Originally Posted by tomm.brz

a hint is that vvt exhaust reached negative values
Exhaust cams aren't allowed to go advanced past 0 so that is a false logging, so I also think is the cam angle sensor
Also cheap to buy, but be aware it needs a really careness to install because the distance must be corrected with special gaskets if needed, to have around 1.3mm of distance between the sensor and the cam plate

Otherwise you can induce misfires, there is a TSB explaining very well this

I mean, just install it, but if you get cel and misfire at least you know why

I replaced it. VVT hasn't come on but exhaust bank 2 is reading now! It won't 0 out though, it's hovering around +3 degrees. I'll reset the ECU again and see what happens. No CEL or misfire

[tomm.brz]

Hope it fixes, could also be the cam actuator that went bad, if it struggles to go to 0

Does it follow the other exh cam?
Does it swing or steady at a value while idling?

[DarkPira7e]

Originally Posted by tomm.brz

Hope it fixes, could also be the cam actuator that went bad, if it struggles to go to 0

Does it follow the other exh cam?
Does it swing or steady at a value while idling?

Steady value. Other cam hovers around 0 so no, it's not following the same value but it does follow the up/down trend while driving.

EDIT: After letting it idle for 10 minutes, it is following the other cam and zeroing out. I went for a 5 minute drive, still not activating

Here's a datalog - https://datazap.me/u/darkpira7e/no-v...?log=0&data=24

[tomm.brz]

tricky
post a log of prolonged idling with warm oil and idle under 950 rpm, with all VVT loggable values activated maybe...

[Ultramaroon]

I think bank 2 exhaust is still mostly dead. I bet that long stretch and chunks of perfectly zero indicate lack of signal.

[tomm.brz]

i don't know, i also get sometime an evenly 0 in my exhaust side, a looot more smoother than intake
and don t have problems
Also i think a lack of signal could have thrown a CEL
and misfires, since cam angle sensors are used to dictate the firing order

[Ultramaroon]

Originally Posted by tomm.brz

i don't know, i also get sometime an evenly 0 in my exhaust side, a looot more smoother than intake
and don t have problems
Also i think a lack of signal could have thrown a CEL
and misfires, since cam angle sensors are used to dictate the firing order

but only one bank? o.0


I'm also surprised no CEL.

[tomm.brz]

this engine is weird, and his oil channels too,

i too have super steady exhaust cams, and stupid retarded-responding intake cams, but no problem at all
I think there is something else in his car stopping the vvt to enable

[JIM THEO]

Did you have the famous valve recall that affects someway the cam oil channels?