Wiring up a 1UZ VVTi Motor - The Triggers and VVTi portion

[Marc D]

Hi guys, I've been contemplating using the megasquirt to wire up Toyota/Lexus' 1UZ VVTI motor.

After gathering and reading much information on how the 1UZ VVTI motor works, is it, to my understanding, that the 1UZ VVTI motor 36-2 crank trigger wheel and oddly spaced 5-2 cam trigger is identical to the 2JZ VVTi motors and that the 2JZ VVTi trigger setting should run the car with just hooking up the crank and cam sensors with the correct VR circuits? I've built plenty of Megasquirts and tuned them in the past, but I have mainly used Hall triggers and sensors for the miatas. Not to mention, this whole MSIII deal is much more complex.

After reading the documentation three times over, am I understanding that the VVTi "input sensing" is through the actual main cam angle sensor?

The VVTi solenoids on the 1UZ VVTi do have their OWN VVTi sensors each (which is separate from the main cam sensor), so will the first on on the engine be ignored since it's run off the main cam sensor? Examining the wiring diagram of the 1UZ VVTi, the sensors appear to be 2-wire VR sensors. Also, The documentation states that a second sensor for the second VVTi, DIY customization needs to be implemented. Does that mean that I still have to build another circuit (i.e. VR sensor circuit) for the megasquirt to read the sensors?

Thanks for the help in advance!
-Marc

[Marc D]

Anyone?

[Matt Cramer]

Hi guys, I've been contemplating using the megasquirt to wire up Toyota/Lexus' 1UZ VVTI motor.

After gathering and reading much information on how the 1UZ VVTI motor works, is it, to my understanding, that the 1UZ VVTI motor 36-2 crank trigger wheel and oddly spaced 5-2 cam trigger is identical to the 2JZ VVTi motors and that the 2JZ VVTi trigger setting should run the car with just hooking up the crank and cam sensors with the correct VR circuits? I've built plenty of Megasquirts and tuned them in the past, but I have mainly used Hall triggers and sensors for the miatas. Not to mention, this whole MSIII deal is much more complex.

You called the cam trigger a 5-2. Do you have any more details on it?

After reading the documentation three times over, am I understanding that the VVTi "input sensing" is through the actual main cam angle sensor?

VVT #1 uses the main cam angle sensor; the other channels use their own sensors.

The VVTi solenoids on the 1UZ VVTi do have their OWN VVTi sensors each (which is separate from the main cam sensor), so will the first on on the engine be ignored since it's run off the main cam sensor? Examining the wiring diagram of the 1UZ VVTi, the sensors appear to be 2-wire VR sensors. Also, The documentation states that a second sensor for the second VVTi, DIY customization needs to be implemented. Does that mean that I still have to build another circuit (i.e. VR sensor circuit) for the megasquirt to read the sensors?

Thanks for the help in advance!
-Marc

Yes, you're going to need more VR conditioners for this one - one if the VVTi is only on the intake, three if you're using intake and exhaust.

[Marc D]

You called the cam trigger a 5-2. Do you have any more details on it?

I read this topic about the 1UZ VVTi Motors:
http://www.msextra.com/forums/viewtopic ... 94&t=46251

Then I read this:
http://www.v-eight.com/tech_forum/viewtopic.php?t=1588

Then I found this about the 2JZ VVTi motors and the wheel decoder:
http://www.msextra.com/forums/viewtopic ... =2jz+wheel

Per James, It's an irregular trigger on the cam lobes. On other forums, some people are calling it a 5-2 wheel since the third tooth is offset when the other two teeth are spaced "It's hard to understand it for me, since triggering and cam logging is still a grey area for me. But maybe someone could shed a little more light since information is far and sparse.

VVT #1 uses the main cam angle sensor; the other channels use their own sensors.

So will we ignore the first VVTi sensor? Or should I use both VVTi's sensors independently from the actual cam sensor?

Yes, you're going to need more VR conditioners for this one - one if the VVTi is only on the intake, three if you're using intake and exhaust.

Gotcha. Already contacted JBperf about his new VR Conditioner 2.1V.

[Marc D]

any more help?

[Matt Cramer]

I'm not sure you would use the camshaft position sensor if the VVTi sensors all have that 3 tooth pattern.

[Marc D]

I'm not sure you would use the camshaft position sensor if the VVTi sensors all have that 3 tooth pattern.

yea, thats exactly what im questioning. since the camshaft has its own wheel pattern, how is the vvti sensors being read? if its that much more different, would it be necessary that a code would have to be written for megasquirt to control the dual vvti?

[Marc D]

more info on Lexus's V8 motor. im sure a lot of this also pertains to 3uz since it is exactly the same with the difference of the higher displacement and thinner wll inbetween the cylinder.

http://www.msextra.com/forums/viewtopic ... ti#p361197

This is a very interesting read....so does this mean the 1uz motors use a single tooth for the actual cam sensor and the vvti sensors use the irregular spaced three tooth wheel pattern? or maybe we can ignore the single tooth wheel, run the cam sensors off the vvti, then it should be ale to sense the other vvti cam sensor no problem i hope.

but that does bother me about the 2JZ vvti trigger settings. will a code have to be written for megasquirt control the 1uz vvti motor since the 2jz trigger setting only supports 6 cylinders?

[Marc D]

anyone else?

[jsmcortina]

but that does bother me about the 2JZ vvti trigger settings. will a code have to be written for megasquirt control the 1uz vvti motor since the 2jz trigger setting only supports 6 cylinders?

Supporting 8 cyl is not too difficult IF the phasing information is known. It will take a few minutes only to add a first draft with a guessed phasing. You would then need to test on an actual engine (strobing at cranking with the plugs out) and confirm the timing and phasing.

This is just the basic engine operation without the VVT stuff.
I skimmed through the links you posted, but didn't spot any information on the VVT cam signals.

James

[Marc D]

Thanks for the reply James.

I think that previous post with the word docs had the information on the vvti cam sensor signals as well as a little information about the phasing which doesnt tell much in regards to the crank.

I'll update this thread as the project advances along. when that time comes, I'll definite be posting some msqs and logs regarding the crank and vvti sensors.

[smohekey]

Hi guys. I'm in the process of wiring up an MS3x for use on a 3UZ-FE with VVTi. The VVTi set up on this engine is identical to the 1UZ-FE. I've been doing a lot of reading and investigation, and if my understanding is correct, we can't use the main cam as the input for vvt cam 1, as the phase of the main cam sensor is not linked to the phase of the vvt cam sensor (they're a different tooth count, and the phase changes as the vvt angle changes). It is my belief that the crank and main cam sensor must be used exclusively for engine position decoding, while the two vvt cam sensors must be used for vvt position decoding. Is this possible with the current code? It appears that TunerStudio would not allow it.

I'm dedicated to getting this working, so can supply any debugging/testing/etc help that is needed.

[smohekey]

Actually, I think I've just had an epiphany and understand this now. The Toyota VVTi system uses a 36-2 wheel on the crank, and does NOT need a cam signal to decode crank position. So instead of connecting the outer cam signal, we only connect the vvti cam signals and the crank signal. Is this correct?

[Marc D]

Thats what I was curious about with my questions, but you would still need a cam signal to run sequential injection. I was thinking that we would ignore the cam sensor itself and base the cam timing off the unusual spaced VVTi trigger.

I'm interested on what your setup is looking like right now, as I will be attempting this later. It would be helpful if we can at least get a trigger pattern logged for the VVTi triggers, but I dont have the engine sitting to test. Maybe you can hook up your MS3 to log the trigger pattern?

[smohekey]

Yeah, after thinking about it more, I can't see how it would work without using crank, cam, and two vvti sensors.

I'm not yet ready to turn anything over as I have a backlog of work to do on another car first, however I do have everything I need for the 3uz-fe install once I get to it. I will update this thread when I know more.

[smohekey]

In order to get full sequential, we would need to use crank and cam sensor, correct? My understanding of the vvti system is that the two cam sensors are situated on the cam wheels themselves, while the vvti sensors are situated on the CAMS themselves. The phase of the two (cam wheel vs cam) is going to change depending on the position of the vvti advance/retard. From http://en.wikipedia.org/wiki/VVT-i: "VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position."

All this tells me that we need to use crank, cam, and the two vvti sensors.

OR, do we use one of the vvti sensors as the cam sensor, and ignore both cam sensors? Is the 4-1 pattern of the vvti sensor enough to identify TDC right though its sweep of adjustment?

[jsmcortina]

I'm not seeing the need for the cam sprocket pickup. The crank and cam alone _ought_ to be enough. However I can't say for sure without seeing composite logs.

James

[smohekey]

Yeah, I think you're right. I've been over thinking it and the fact there are so many sensors has been confusing me. The cam can only ever sweep 45 degrees, so would be a maximum of half of that out of phase. The 4-1 signal would therefore be enough to identify TDC with the crank signal. Once I have all the loom rewired and everything, I'll get some logs to confirm.

[Marc D]

That would be awesome if is true. please keep us informed. Thanks!

[Mario]

Bump