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QUOTE (njccmd2002 @ Nov 29, 2011 - 6:43 AM)

>^^^ instructional video
No video available, but here's a quick diagram and the nitty gritty dirty but (hopefully) easy to understand explanation of VVT-i.

Basically, VVT-i uses a few main sensors to determine RPM, load, etc. Mainly, it uses the crank and cam position sensors, as well as the TPS. The ECU interprets the signal of these and sends a signal to the oil control valve (OCV), commonly called the VVT solenoid or sensor though it's actually neither. This valve controls oil flow to the VVT-i controller on the cam shaft. If the OCV sends the oil one direction, timing is advanced. If it sends it the other direction, timing is retarded. Or it can maintain a certain position, maintaining timing and behaving as any other engine would.
One commonly made mistake about the BEAMS is that the VVT is on/off, and it's definitely on after 4,500 RPM. To be exact, this is VVT-
i. The i is for intelligent, meaning the VVT is working 100% of the time, from startup to redline. When you start the engine, the timing is retarded. This produces an easier startup. When you go WOT, timing is advanced. The only reason for the 'kick' that the BEAMS produces at 4,500 RPM is because the motor has come into its power band. The VVT is already fully advanced before the revs get to 4,500.
The VVT-i controller on the cam shaft is the most expensive part of the system to replace. It cannot be taken apart and serviced or cleaned. Of course, a few brave people will still try, but I am not one of them. The issue with my BEAMS is that my VVT-i controller is seized in what I assume is advanced timing, since I have limited low end power and plenty of top end power. Also, the issue seems to be getting worse, as fuel mileage is going down. Our driving certainly hasn't changed, so the motor is drinking more fuel. 21 mpg from a lightly driven 2 liter BEAMS is pathetic, since my 3 liter 2JZ is pulling 23 mpg easily. I used to get over 30 mpg with the BEAMS, and now it's definitely down in the low 20's.
I do have a spare VVT-i controller from my Greytop that I could put on my Redtop, but if I do, I will change the timing belt, oil pump, and water pump. Doing some quick shopping tells me that I will be into that project $440 plus my time and hassle to pull the motor out. And the rather large gamble of if the VVT controller from the Greytop is any good. When it isn't on the motor, I can put 20 psi of air to it and take a pair of needle nose pliers and theoretically, I should be able to turn it. However, that doesn't actually tell me if it's functional or not. Why potentially waste nearly $500 plus my time when I'm looking into some other engine sets that have enough extras to make them worth my while? LSD transmission, OEM intake as a spare to the one I already have on the way here, SS-III two pot brakes, some even with the BEAMS gauge cluster. And I can part out my current engine or sell the swap as a whole with my spare VVT controller and recoup some cash. Yes, I would still spend more money for a new BEAMS than I would if the spare VVT controller works, but there's no way I could get all of the extras for the money over what I would spend for a new motor set after selling a few things. Plus if I can be bothered to pull this motor out, I can't be bothered to put it back in. I've had enough frustration with it, it's time to move on to different parts of the car. The motor work will be finished very soon and we will be moving on to body work.