Stage 3 cams - VVT not engaging

[AJRFulton]

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The VVT has been a thorn in my side. I had my car at the tuner today and the VVT is still not engaging.

Since last year car has had

Loom salvaged from a breaker
New OEM solenoid
New ECUmaster ECU
New OEM VVT Sprocket

The only thing that stays the same are the stage 3 Piper cams.

These were cleaned, and had high pressure air blown through - appeared to have no blockages then reinstalled. The head was pretty spotless at reassembly, and reassembled as per torque/clearance values in 2zz manual.

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That was the engine prior to being bolted together.

Could the cams even prevent the VVT from working? What could be wrong with them? It is the only bit that is a constant.

[Dev]

When the VVT sprocket was installed on the cam was it in the unlocked position?
There is a TSB issued that states that the VVT needs to be unlocked otherwise the lock pin can get jammed preventing the stator from moving.

[shiny]

When the VVT sprocket was installed on the cam was it in the unlocked position?
There is a TSB issued that states that the VVT needs to be unlocked otherwise the lock pin can get jammed preventing the stator from moving.

I unlocked mine using compressed air.

[AJRFulton]

When the VVT sprocket was installed on the cam was it in the unlocked position?
There is a TSB issued that states that the VVT needs to be unlocked otherwise the lock pin can get jammed preventing the stator from moving.

It was installed unlocked as per manual.

This is the 3rd engine this issue has manifested itself on, the inlet cam is the only constant.

What may have happened is the engine had been installed, oiled and turned over, then sat for 5mths after the accident. Corrosion siezed?

[Gaz2405]

Does the tuner have any logs you could share.

Assuming tuner is used to emu black and switchable tables for VVti etc. (They look like a proper outfit)

Can you hear the solenoid firing in test mode ?

Have you tried different solenoids, assume occ is clear and clean etc.

[AJRFulton]

Does the tuner have any logs you could share.

Assuming tuner is used to emu black and switchable tables for VVti etc. (They look like a proper outfit)

Can you hear the solenoid firing in test mode ?

Have you tried different solenoids, assume occ is clear and clean etc.

Solenoid is firing and duty cycle is fine.

The VVT angle isn't moving though.

[Gaz2405]

Hmm, does sound mechanical then.

[Call the midlife!]

Probably difficult to check but is it getting enough oil pressure to cycle it? I don't know what the stage 3 cams are designed to do but the stage 2s I had in, together with the uprated valvetrain put a lot of extra strain on the chain, especially at lower revs.

[AJRFulton]

Probably difficult to check but is it getting enough oil pressure to cycle it? I don't know what the stage 3 cams are designed to do but the stage 2s I had in, together with the uprated valvetrain put a lot of extra strain on the chain, especially at lower revs.

In terms of oil pressure, parameters look fine, maybe even slightly high.

At idle and warm I'm about 30-35 psi at idle (1200rpm). Cold 60-80 psi. Capillary oil gauge (race tech)

This has been a pressure that worked fine before.

[Call the midlife!]

Aside from all previous comments and your own suggestions it only really leaves a manufacturing flaw with the cam, maybe the alignment pin is off but you'd expect them to be assembled in a jig.
Or the vvt clutch unit is faulty, assuming you've used the same one across all three installations?

[AJRFulton]

Aside from all previous comments and your own suggestions it only really leaves a manufacturing flaw with the cam, maybe the alignment pin is off but you'd expect them to be assembled in a jig.
Or the vvt clutch unit is faulty, assuming you've used the same one across all three installations?

No this is a new Toyota VVT.

The piper cams have worked previously, but this is the third engine this has raised its head

[shnazzle]

Stupid question maybe but.. Checked for blockages on the cam and the block? Blown it out with air? No rogue dot of sealant anywhere blocking the oil?
If the cam's passages are blocked then the issue would of course transfer between blocks. 

Then there's electronics; you know the ecu is sending the signal, but can you verify that it is actually triggering the valve? I.e. the wiring is correct with any necessary pull-up/down resistors. 

Can you verify that the cam angle isn't changing? Or is it changing but the ecu isn't registering the change in angle? 

And the obvious question... Has it been set up right? 

[Call the midlife!]

No this is a new Toyota VVT.

The piper cams have worked previously, but this is the third engine this has raised its head

I can't remember off hand which cam carries the position sensor vanes but are they all intact, not lost a chunk or anything so the sensor is getting duff information?
A bit out there maybe but we're in clutching at straws territory almost...

[AJRFulton]

Stupid question maybe but.. Checked for blockages on the cam and the block? Blown it out with air? No rogue dot of sealant anywhere blocking the oil?
If the cam's passages are blocked then the issue would of course transfer between blocks.

Then there's electronics; you know the ecu is sending the signal, but can you verify that it is actually triggering the valve? I.e. the wiring is correct with any necessary pull-up/down resistors.

Can you verify that the cam angle isn't changing? Or is it changing but the ecu isn't registering the change in angle?

And the obvious question... Has it been set up right?

It's all pretty plug and play. I'm using the MWR 1ZZ to 2ZZ loom harness, so even less scope for an issue.

Used a stethoscope to listen for the VVT Sprocket moving, but doesn't appear to. Cam position lobes are intact.

I just cannot see where a blockage would be. There's no sealant around these systems, and again it's the 3rd different engine to have these problems.

[Dev]

It was installed unlocked as per manual.

This is the 3rd engine this issue has manifested itself on, the inlet cam is the only constant.

What may have happened is the engine had been installed, oiled and turned over, then sat for 5mths after the accident. Corrosion siezed?

I doubt corrosion because the oil will still be on the internals even if the engine was sitting for many years . 

 The only thing I can think of to check is to see if the magnetic induction cam sensor is producing a clean oscillating 5V signal. It's a simple diagnosis by probing the wires attached to the cam sensor using a multimeter. It's better if you have an oscilloscope to check if its square.

 If the magnets on the end of the cam are not in perfect alignment due to a manufacturing defect it can alter the cam signal and depending on what ECU you have it cannot move the stator until it knowns the position of the cam. Aftermarket ECUs generally do not have any diagnostic functions or limp strategies. 
With the OEM ECU it will indicate a check engine light and stop the VVT. It will also fire the spark plugs multiple times to keep the car running in limp mode. If you can run the car using the OEM ECU might indicate a code that would tell you where to look. 

[Gaz2405]

Have these cams ever worked successfully in any of your builds, it could be a cam issue.

Like Dev says it may not be picking up the signal.

Can the cam timing be adjusted prior to "lift"?

[Gaz2405]

Do you have a standard cam you could swap in to try?

[shnazzle]

It's all pretty plug and play. I'm using the MWR 1ZZ to 2ZZ loom harness, so even less scope for an issue.

Used a stethoscope to listen for the VVT Sprocket moving, but doesn't appear to. Cam position lobes are intact.

I just cannot see where a blockage would be. There's no sealant around these systems, and again it's the 3rd different engine to have these problems.

Just had visions of a piece of sealant or some kind of other FM maybe finding its way into the holes in the cam.
It's my understanding that the oil flows from the block, into vvti chamber/cover, into solenoid, into cam, into sprocket.
So if there's a blockage in the cam, the oil won't make it into the sprocket to change the angle.
If there's a blockage in the ocv, then it won't make it into the cam.
If there's a blockage into the vvti cover, then it won't make it into the ocv.

[AJRFulton]

Have these cams ever worked successfully in any of your builds, it could be a cam issue.

Like Dev says it may not be picking up the signal.

Can the cam timing be adjusted prior to "lift"?

They have worked, yes.

[AJRFulton]

Just had visions of a piece of sealant or some kind of other FM maybe finding its way into the holes in the cam.
It's my understanding that the oil flows from the block, into vvti chamber/cover, into solenoid, into cam, into sprocket.
So if there's a blockage in the cam, the oil won't make it into the sprocket to change the angle.
If there's a blockage in the ocv, then it won't make it into the cam.
If there's a blockage into the vvti cover, then it won't make it into the ocv.

It's possible, but I can't see it always happening.

Because I'm using run in oil it has UV dye 8n it. It looks like it's everywhere. Will need to properly look.

[Carolyn]

Just because the oil gets into the hub, that doesn't mean it gets there with sufficient volume and pressure, so a partial blockage could cause the problem.  Having read the thread, it would seem either the cam sensor is faulty or the oil way in the cam is restricted.

[mr2garageswindon]

3 Engines same problem.. I'd be looking at ecu not operating it correctly if was same ecu for all 3 engines.
Can you reconnect a 2zz ecu easily just to test the theory?

[Gaz2405]

3 Engines same problem.. I'd be looking at ecu not operating it correctly if was same ecu for all 3 engines.
Can you reconnect a 2zz ecu easily just to test the theory?

Pretty sure the EMU black is new for this season.

I was thinking about this last night, possible wiring gremlin, but then the solenoid wouldn't fire?

The VVt actuator is new and unlocked.

I'm thinking it's got to be a tolerance issue with the cam position sensor or the cam reluctor (not sure if that's the right term)

[AJRFulton]

3 Engines same problem.. I'd be looking at ecu not operating it correctly if was same ecu for all 3 engines.
Can you reconnect a 2zz ecu easily just to test the theory?

I don't own one.

Popped into JSpec and borrowed a ECU and a VVT Sprocket.

3 engines, the only constant is the camshaft.

[Carolyn]

That makes sense.  So the oilways in the camshaft are restricted and not delivering the required pressure/flow rate.