Closed loop/open loop @ WOT

[Bruce Plecan]

> But I guess I would ask........
> Whether the ECU uses the O2 lambda signal or not in open loop WOT it
doesn't
> stop a monitoring device displaying it's output, does it?

How clever,
At this stage read the archives.

> Does it still make sense open loop to read the sensor so a human can
> determine if something has gone horribly wrong?

OK, wire up a LED, for on, under .44v.

> The ECU just uses a fixed (learnt or default) fuel setting (injector duty
> cycle, probably near max) for WOT but won't the O2 sensor still indicate,
if
> in a modified car, the setting the ECU is using is running the car lean
and
> hence one needs to modify something else like injector size to compensate.

Again read the archives
Again read the plugs.

> (Oh.. does the ECU learn a setting or do they normally just use a fixed
> setting in open loop for injector duty cycle)

Depends on ecu, strategy.

> Of course in a ECU which is programmable one could change this setting but
> some Toyota ECUs (Supra) don't allow reprogramming.

Welp, if they can't be, then a different one is needed if you want to do any
tuning
Grumpy
>
> Pete
>
>
>
> > Master of Disaster wrote:
> > >
> > > I think you should sell your Supra and buy something American, with
> > > an LT1 or LS1 engine. :^)
> > > They stay closed loop at WOT, or thus I have been led to understand.
> > > I am not bad-mouthing the Supra-- it's a beast, but if it goes open
> > > loop at WOT, I don't want one.
> >
> > Actually all LT1s and LS1s go into open loop at WOT.  Why
> > would you not
> > want the PCM to go into open loop at WOT?  I guess it would
> > make tuning
> > up there a little easier...
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