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Re: Tuning in Open Loop for Newby



> After reviewing a bunch of EPROM bins, I have a question about tuning. My
> understanding is that the tuning is for closed loop operation. But to
tune,
> you set the closed loop enable temp way high to keep the ECM from entering
> closed loop.

**Only** if there are major problems, or a totally new calibration.
If you've just changed cams heads, shouldn't need to.
If your running anything other then at the limits of the calibration, then
closed loop will be fine.

> So now, are you tuning in open loop or closed loop?

Again depends on what your doing.  If you have an open loop problem like
during warm up then you have to cure that.

 If open loop
> is nothing more than the closed loop tables without O2 feedback, what are
all
> the open loop AFR correction vs. MAP and AFR correction vs. coolant temp
> tables for?

There are different modes at different times, and they all must balance out
for drivibility.
The O2 sensor is the final trim on the calibration, and helps with
emissions.  Too rich usually feels *better* but does nothing but waste gas.

 Seems to me that these tables would interfere with proper tuning
> for closed loop operation. If you tune with those corrections applied, and
> then you drive in closed loop, seems that your tuning would be inaccurate?

Again, on 90% of the tuning needed it's just a final *tuning* that is
needed, and not a total calibration.
Your one or the other open  loop or closed loop, I don't quite understand
what you mean by doing one and goofing up the other.  If ya try it, and
experiment a little it will be a whole lot clearer, trying to imagine stuff
can often be more confusing, then just doing it
Kinda a Zen thing.  Just be one with the ecm / engine and let them tell you
what they want.

> Also, it was mentioned a while back that setting ignition timing advance
to
> just before knock occurs at all RPMs is not always the best setting.

True.

 If
> that's the case, what criteria is used as your tuning goal? Best
acceleration
> under WOT? Best mileage? Etc.

Depends on where your tuning.
WOT is usually measered in Distance vs time
Cruise very well would be MPG
Bruce
>
> Thanks
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