[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[tuner23] Re: Air Temp Sensor?

Jeff,

In the PE strategy spark timing is retarded as a function of VAT.

PT WOT
The VAT functions at 2C56 and 2C72 in the LA3 would retard spark at high VAT, except the output of those functions are basically multiplied by 0.

Those VAT tables are ignored by the LA3 based on the gain at location 2C00 hex = 80 hex.

Location 2C00 hex= 80 hex means....

Air temperature based spark adder (Part throttle) =
(80-80)/80 * VAT function value from 2C56 + 80/80 * ACT table value from 3518.

Air temperature based spark adder (Wide open throttle) = (80-80)/80 * VAT function value from 2C72
+ 80/80 * ACT table value from 35A0.

Therefore in the LA3 spark timing is no longer explicitly a function of VAT.

--- In tuner23@y..., Jeffrey Engel <jengeltx@y...> wrote: 

I've been unable to find the code that lead me to
believe high ACT temps pulled ignition timing.  At
this point, I have to conclude that my thinking was
most likely wrong.

>--- dcolvin_xr4@y... wrote:
> Looking at Jeff Engel's LA3 disassembly my best
> guess to date is that:
> > ACT effects boost control and spark timing but not
> fuel control.
> PT WOT
> The spark advance adder functions at 2C56 and 2C72
> use VAT and not ACT.
> PT WOT
> The spark advance adder tables at 3518 and 35A0 use
> ACT for the > x-axis.
> > Based on the data in the tables at 3518 and 35A0 a
> maximum of 2 degrees spark advance is added below 60 degrees F.
> > Also based on the calibration data at 3518 and 35A0
> spark timing is never retarded based on ACT.



to post: tuner23@yahoogroups.com
to unsubscribe: tuner23-unsubscribe@yahoogroups.com
to change email delivery settings: http://groups.yahoo.com/group/tuner23
to share a file: http://groups.yahoo.com/files/tuner23/

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/