2JZ VVTi

[jsmcortina]

So, it is not that you're controlling oil pressure directly, and working against a spring so a certain oil pressure amounts to a certain advance angle. Instead, you're operating a valve that can actively steer the timing piston in either direction, and optionally also hold it at whatever the current position is.

Sounds like most of the other VVT implementations then.

James

[porelmundo]

some diagrams.

[porelmundo]

Any progress with the code?

[porelmundo]

Some scopes, crank, cam. only positive side, not from my engine but identical than my.

[gross polluter]

Thanks for posting this info, porelmundo. Just obtained a VVTi 2JZGTE today for a project and came here to see if there was anyone that had this running yet.

[porelmundo]

Thanks for posting this info, porelmundo. Just obtained a VVTi 2JZGTE today for a project and came here to see if there was anyone that had this running yet.

My engine is running since Megasquirt 3 first 100 and is running perfect, without the msx board, by that time was not available so I fabricate a custom board for the extra stuff connected to processor header, running the stock turbos in sequence as the stock setup, working better than factory, boost control and a lot of other mods.

[jsmcortina]

I tested the code today and it needs some more work.

James

[porelmundo]

Ok James thank you

[gross polluter]

An observation I made with my engine is the ignition system is wasted spark, opposed to the COP used on non VVTi 2JZGTE engines. Thinking more about the cam and crank trigger arrangement, it seems that it would a bit difficult to interpret sequential fueling and ignition from this arrangement due to the evenly spaced cam trigger.

Looking at the trigger logs above, one engine cycle has two cam pulses and another cycle has a single cam signal. Being that these signals are so close to the missing teeth on the crank signal I could see how the camshaft changing timing would cause this pattern to invert, in the sense that one of the pulses crosses the missing teeth causing the cycle that had only a single pulse to now have two pulses and vice-versa.

Seems that even for Toyota, this was a potential issue. I don't have wiring diagrams available at the moment for the 2JZGTE VVTi, but I'd imagine the fueling was batch fire as well if the ignition was wasted spark, with this particular arrangement.

[porelmundo]

but I'd imagine the fueling was batch fire as well if the ignition was wasted spark, with this particular arrangement.

It is semi sequential, Toyota after a few years drawback to waste spark because there is no much fuel econy on sequential, and make less complex vvti functionality. 2jz are little expensive to run and many people change they're engines to wasted spark, coils are stronger and better reaults.

[jsmcortina]

I worked around that by only looking for the cam pulse between certain crank teeth. My code seems to work ok.

James

[gross polluter]

Reading the manual on the current VVT code, if I read it correctly, the current vvt code should work provided the engine is running semi sequential and wasted spark. I'd imagine you'd set it up accordingly:

No VVT's: 1
Cam decoder: Standard
on/off or PID: PID

Control interval: Synced to cam
Range check measured angles: Yes

More duty means: Advance
Use hold duty: ON
Hold duty: 50%

Input: Main cam
No teeth: 3
Output: VVT
Intake/exhaust: Intake

It seems that setting it up this way should work for semi sequential and wasted spark configuratons?

[porelmundo]

As I understand all that is correct, exept for the tooth count because of two different patterns one is a Y pattern and the other that I know is what we have 3 evenly spaced. So of you select 3 you need to difference from this two.

[porelmundo]

James, can I test the code? What can I do to help.
Thank you for your support.

[gross polluter]

I'll be up in running in two weeks, and will be more than happy to provide whatever info is needed to help make this work too.

[jsmcortina]

Check out alpha 14.

James

[porelmundo]

Yujuuuuu I will Test it rightnow I report in a few hours
Thank you

[porelmundo]

I been testing alpha 14, when you select 2jzvvt wheel mode all my crank wheel settings get hidden, so I suppose that all setings are included in the code, but I try to start the engine with no luck, and also I have no spark, rpm drop every other second, is this mode only for log? Explain me more. Crank angle is 155.
Thank you James

[jsmcortina]

As with all custom wheels yes the settings are built in.

Is you cam sensor hooked up and configured correctly?

Please post a fresh composite log.

James

[gross polluter]

I do not yet have a running engine, however, I have an engine on the stand that I can spin up to about 300 rpm with the starter for testing. I made the same observation as porelmundo in that the trigger angle is way off. I did not observe any sync losses until I began to advance the cam, beyond a certain angle sync is lost and will not recover until I retard the cam timing. Below the point of the cam angle that causes lost sync, I did not observe any other sync issues. Spark output I can say for sure works fine.

In wheel mode set as a single 36-2 crank wheel, I observed a tooth #1 angle of 160 degrees.

I will post all of the info I gathered for this experiment in a little while.