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Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Mar 24, 2014 9:37 am

AvivB wrote:TVSV open when throttle is open wide enough...
I don't think it related to air volume as it can open on low rpm without boost (low air volume) and it can be closed in high rpm (high air volume).


You sure about that?
It shouldnt do.
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Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Mar 24, 2014 9:43 am

I saw it open in less that 2000 rpm and closed when you release the throttle at 6000 rpm...

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Mar 24, 2014 2:51 pm

So the light will come on even when the car is still in vacuum? If you can confirm this you can save me a lot of work.

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Mar 24, 2014 6:17 pm

If the throttle is open so there is no more vacuum... :)
It turns on when the pressure is around 0 (zero) and turns off when it drops bellow around -5inHg (low vacuum).

What are you trying to do that you want to use this signal?

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Apr 07, 2014 10:12 am

AvivB wrote:If the throttle is open so there is no more vacuum... :)


... thats why there is a TVIS vac reservoir.
It can be activated without there being vac in the inlet manifold.

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Mon Apr 07, 2014 7:31 pm

In that context (and most others) the ECU cares about engine load and little else.

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Tue Apr 08, 2014 5:35 am

MWP wrote:
AvivB wrote:If the throttle is open so there is no more vacuum... :)


... thats why there is a TVIS vac reservoir.
It can be activated without there being vac in the inlet manifold.


Yep, I'm well aware about the TVIS vacuum reservoir...
It activated at low rpm and released at 3k rpm so it need something to keep it open at the beginning of the acceleration when throttle is wide open (in some cases).

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Tue Apr 08, 2014 5:38 am

Simba wrote:In that context (and most others) the ECU cares about engine load and little else.

Not sure I understand what you mean...

Re: How the ECU knows the gearbox is in 1st/2nd gear or 3rd

Tue Nov 25, 2014 2:18 am

the engine load: He meant it depends on the AFM readings and engine rev at that time.
and yeah the ECU senses car speed. the highest sustained engine loads are recorded when the car moves faster, it could be only engine load related. we could prove that with readings :twisted:
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