2jz Vvt Ftl!!!!!!

[AE86slut]

settle down sunshine

*Blows kiss in Ed's direction*


Thanks for that Dave. Very helpful!

Cheers,

Jeremy.

[sideshow]

its variable pulse but then i think it uses the cam sensor as a reference
the variable pwm yr talkin about is onl;y good for idle motors or extra injectors

[Mos]

At the risk of being another off topic post the most likely thing that happens is a servo loop.
The ECU applies a certain pulse width to the solenoid and watches, via the cam sensor, what the resultant advance becomes. If the resultant advance does not match the desired advance the ECU would change the pulse width and continue watching, eventually finding a pulse width that will give the desired advance for that particular set of conditions.

Something like this could account for changes in oil viscosity, pressure, temperature, etc. It wouldn't be impossible if the ECU built a table and periodically checked to see if the table is still accurate.

In the absence of literature to that effect we can only speculate as to what it actually does. I don't know if Autronic and Motec specify how the cam advance is controlled, but that would give indication as to what's needed.

I guess it would be possible to use a non-VVTi aftermarket ECU, and build up a table of pulse width vs advance vs rpm (if there are no other significant factors), and maybe that could work.

As to checking the solenoid, you could try applying a varying pulse width and see the result (You obviously need the engine running). The scans posted by GT suggest the duty cycle is around 33% - you could start there and work away. (Edit - I should've read all of the replies )

If I were to scope the VVTi signal (on the 1G-FE) at various rpms, would that be useful to you? (or would I just be wasting time?)

Mos.

[Ben Wilson]

its variable pulse but then i think it uses the cam sensor as a reference
the variable pwm yr talkin about is onl;y good for idle motors or extra injectors

You can set the duty cycle anywhere from 0-100% at (I think) 32 points along the rev range, sounds to me a lot more useful than just drving injectors and idle motors.

[sideshow]

well most ecus can do pwm so its prety basic

anyway i dont really care if they fix iit or not

but from most of the info i have gathered

the vvti needs 2 things
one is the oil solenoid and the other is
the position of the vvti gear

its easy to turn the thing on and off to get certain advances
but the std toyota ecu knows exactly where the vvti gear is thru the cam sensor

there is a better explainatiuon of why some ecus can and some cant do vvti
best person to talk to is someone clued up at autronic or motec
because these 2 systems are well known to do vvti