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post #1 of 33 (permalink) Old 04-07-2007, 02:08 AM Thread Starter
 
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Megasquirt and VVT?

Hi,

I have a 164 TS with VVT. If I had to use Megasquirt, will the VVT still work?

Thanks

Ryan
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post #2 of 33 (permalink) Old 04-07-2007, 02:32 AM
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G'Day Ryan,

I know little about MS but I'm sure there is a spare output that could be used to control the VVT.

However MS is very much a DIY project, you would have to determine under what conditions you would want the valve timing to change.

This is really the sort of thing that should be discussed on the MS forum.

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post #3 of 33 (permalink) Old 04-07-2007, 02:40 AM Thread Starter
 
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Hi Craig,

I do not even know when the VVT comes in when operated by stock ECU??!!!

Will check and try to make my mind if it is worth it or not to go MS.

Thanks
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post #4 of 33 (permalink) Old 04-07-2007, 03:30 AM
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It's not that easy, it happens at about 1300 rpm but is also dependent upon load.

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post #5 of 33 (permalink) Old 04-07-2007, 09:23 AM
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Actually anything post '84 should be electronically controlled by the tps and has nothing to do with RPM. Pre-'85 is inertia operated mechanical and definitely relative to engine rpm. (84-85 being somewhat relative as those were transition years)

The tps will activate the solinoid from about 56-58 degrees deflection up to full throttle/90 degrees regardless of load, then deactivate again when tps drops below that 56-58 degrees.

If you have 4 wires on the tps (2 wires off one terminal then 1 wire per remaining terminal) and a solinoid on the VVT, the above applies.

TPS is is mearly a trigger/signal wire for the VVT and there is no ECU interaction in regard to the VVT proper, but it will go into open loop when tps detects that range of motion. (ECU is where the 2nd wire on that common terminal goes)




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Last edited by Tifosi; 04-07-2007 at 09:31 AM.
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post #6 of 33 (permalink) Old 04-07-2007, 12:18 PM
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Sorry Tifosi,

Thats on the Spiders (not sure about the S4's). On the T.S. it's controlled by the ECU. However as you suggest, it could be controlled by a throttle position or a specific no. of revs by MS.

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post #7 of 33 (permalink) Old 04-07-2007, 03:15 PM
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<-- can't grasp why it would be any different between models, particularly when commonality of parts and wiring is so widespread, but won't argue the point as I've not got one here to even try (still, I'll give the parting shot that if it is L-jet or Motronic, it is controlled by the tps, not the ECU. But only because I'm rude like that )




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post #8 of 33 (permalink) Old 04-07-2007, 04:01 PM
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And I can produce wiring diagrams if needed.


Ah, what the heck, see the attached pdf (check the lower right corner).
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File Type: pdf motronic_ML41_schematic 75TS.pdf (150.2 KB, 365 views)

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Last edited by Craig; 04-07-2007 at 04:05 PM.
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post #9 of 33 (permalink) Old 04-07-2007, 04:40 PM
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I see VVT ACT down there, but don't see where it connects to the ECU, tps or anything but a what appears to be a junction for that matter. (thanks for trying as I do want to understand, but it's a crap diagram AFA being able to trace anything)

As to the pretty words up above 'blah, blah, function map blah, blah, timing variator', oddly enough, a few spider books say the same thing depending on what one you look at. That doesn't make it right though, just a laymans description.

Is there another diagram available somewhere? I'm actually pretty curious as to how things are routed.

Of course the other way around it would be to disconnect the ECU from the rest of the system right at the multipin harness plug then turn the key on and roll the throttle full on.

If the VVT kicks, then it's tps for sure and nothing to do with the ECU, function map or otherwise. (I'm guessing no-one will be willing to unhook an ECU for such a test though, and I honestly wouldn't blame them)




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post #10 of 33 (permalink) Old 04-07-2007, 05:05 PM
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Quote:
Originally Posted by Tifosi View Post
I see VVT ACT down there, but don't see where it connects to the ECU, tps or anything but a what appears to be a junction for that matter.
Basically it says pin 31 of the ECU goes to a relay which has something to do with the VVT.

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(thanks for trying as I do want to understand, but it's a crap diagram AFA being able to trace anything)
As it's the only diagram in the public domain, it's fantastic!

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Originally Posted by Tifosi View Post
As to the pretty words up above 'blah, blah, function map blah, blah, timing variator', oddly enough, a few spider books say the same thing depending on what one you look at. That doesn't make it right though, just a laymans description.
Well it comes from the section of a manual devoted to the testing of the ECU and it's ancillaries so why mention it if it operates on it's own?

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Is there another diagram available somewhere? I'm actually pretty curious as to how things are routed.
Yes, many but they're too big for here, download the Twin Spark 'S' manual from my site and look at image 75TS_S-00-71.gif and see if you can follow it.

Follow pin 31 of the ECU to S12c (VVT relay) then the output of S12c (pin 87) to S15 (VVT solenoid, but it's not listed as such).

Also follow the wiring from S6 (TPS) and see where it goes.

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Of course the other way around it would be to disconnect the ECU from the rest of the system right at the multipin harness plug then turn the key on and roll the throttle full on.

If the VVT kicks, then it's tps for sure and nothing to do with the ECU, function map or otherwise. (I'm guessing no-one will be willing to unhook an ECU for such a test though, and I honestly wouldn't blame them)
I don't have to, I know how it's connected. You could just believe me , I do know how my car is wired.

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post #11 of 33 (permalink) Old 04-07-2007, 06:09 PM
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Ahh, that's so much better, thanks.

That's some serious daisy chaining of the relays you got going on there. Looks like if any one fails, none will work.

3 of the three tps wires you've got match what L-jet would have, including ECU pin # (2&3) but you lack the 4th wire.

However you do have more pin connectors in use on your ECU. This would explain why the 'function map' description above includes VVT as it's entirely possible that the tps signal has a roundabout contact inside the ECU, but that may or may not mean the actual map controls it, just that VVT gets triggered from within the ECU body. (for all we know, the tps and VVT trigger could connect directly to each other in there. As the tps shows to be a switch type rather than potentiometer, I would presume it's just a trigger device like L-jet at least)

At no point in time did I express or imply that you didn't know how your car was wired. I'm sure you do. I was leaning more towards that the 'how it actually works' portion might be debatable. (that wasn't meant to be rude or smartassy btw)

Now if I'm looking at it right and chasing through the relays properly, it's ECU pin #31 that actually triggers the VVT after some roundabout dancing through the relays and such, correct?

Or more explicitly, the VVT relay is triggered via ECU pin #31 on terminal 85, gets its voltage on connection #30 directly from the #87 on S12d (which is fed by the battery off it's own #30 on terminal), dances through S12a on its #86 terminal which also ties into the Fuel Vapor Control Solinoid (which does what BTW?)

This leads me to belive the VVT could be kicked on by a 12v signal from a megasquirt if all the stock relays were present and it were fed through the wire that came off the #31 ECU multipin with whatever programmable parameters a mega might have in regard to that part of its construction/programming. (ideally there would be a means of tying it into tps position and/or rpm but I've no idea what that particular systme is capable of)




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Last edited by Tifosi; 04-07-2007 at 06:12 PM.
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post #12 of 33 (permalink) Old 04-07-2007, 06:49 PM
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Quote:
Originally Posted by Tifosi View Post
However you do have more pin connectors in use on your ECU. This would explain why the 'function map' description above includes VVT as it's entirely possible that the tps signal has a roundabout contact inside the ECU, but that may or may not mean the actual map controls it, just that VVT gets triggered from within the ECU body. (for all we know, the tps and VVT trigger could connect directly to each other in there.
Trust me, it's revs/load. This info has come from others I trust.

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As the tps shows to be a switch type rather than potentiometer, I would presume it's just a trigger device like L-jet at least)
Yes, Idle position and WOT.

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At no point in time did I express or imply that you didn't know how your car was wired. I'm sure you do. I was leaning more towards that the 'how it actually works' portion might be debatable. (that wasn't meant to be rude or smartassy btw)
I understood that.

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Now if I'm looking at it right and chasing through the relays properly, it's ECU pin #31 that actually triggers the VVT after some roundabout dancing through the relays and such, correct?
Yes.

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Originally Posted by Tifosi View Post
Or more explicitly, the VVT relay is triggered via ECU pin #31 on terminal 85, gets its voltage on connection #30 directly from the #87 on S12d (which is fed by the battery off it's own #30 on terminal), dances through S12a on its #86 terminal which also ties into the Fuel Vapor Control Solinoid (which does what BTW?)
See my site re the TS start sequence.

Fuel vapor recovery is part of the closed fuel system, vapor is collected in a container above the fuel tank ( and in a cannister filled with charcoal). The valve opens every now and then to let the vapors be sucked into the inlet manifold.

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This leads me to belive the VVT could be kicked on by a 12v signal from a megasquirt if all the stock relays were present and it were fed through the wire that came off the #31 ECU multipin with whatever programmable parameters a mega might have in regard to that part of its construction/programming. (ideally there would be a means of tying it into tps position and/or rpm but I've no idea what that particular systme is capable of)
Throttle position is a less than ideal way of determining when to change the valve timing. This is why the Motronic which is later than and has more smarts than L-Jet doesn't use it. But it could be done.

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post #13 of 33 (permalink) Old 04-07-2007, 06:59 PM
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Quote:
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I understood that.
Cool :thumbsup: (I hate it when people misinterpret me. I promise everyone definitely knows when I'm being a snot )

Quote:
Fuel vapor recovery is part of the closed fuel system, vapor is collected in a container above the fuel tank ( and in a cannister filled with charcoal). The valve opens every now and then to let the vapors be sucked into the inlet manifold.
So there no canister elsewhere that feeds the inlet pre-throttle body without intervention by that device then.

Presumably your setup is a bit 'cleaner' then as the conventional canister does have the potential to leak a bit of vapor.

Quote:
Throttle position is a less than ideal way of determining when to change the valve timing. This is why the Motronic which is later than and has more smarts than L-Jet doesn't use it. But it could be done.
Not knowing the megasquirt systems, is there any reason to believe it couldn't be a combination of tps (potentiometer type) and a MAP sensor?

I ask as I'm currently putting together an SDS setup which works along the lines where it compares one to the other and if the parameters are X on each, it'll trigger a signal wire to a relay or what have you. ('accelerator pump' function however is a tps thing)

*not trying to hijack the thread btw, just getting some ideas out there that the original thread author might be able to use. (it's just that I have a roundabout non-linear way of thinking )




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Last edited by Tifosi; 04-07-2007 at 07:02 PM.
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post #14 of 33 (permalink) Old 04-07-2007, 08:06 PM
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Quote:
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So there no canister elsewhere that feeds the inlet pre-throttle body without intervention by that device then.

Presumably your setup is a bit 'cleaner' then as the conventional canister does have the potential to leak a bit of vapor.
See Group 40 in the 'S' manual you downloaded.

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Not knowing the megasquirt systems, is there any reason to believe it couldn't be a combination of tps (potentiometer type) and a MAP sensor?
Nope, but somebody has to write the code which was the point of my original reply.

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post #15 of 33 (permalink) Old 04-07-2007, 11:09 PM
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Im not sure if this has been said or asked.. but if you stuck constant 12v on the vivt whilst the engine is running, would it not be fully advanced constantly?

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