First off-
1227747, $42 Mask, TBI, TunerproRT

I know that within Tunerpro, I can play with the TPS ALDL data to get a % TPS value.
For example, Something along the lines of N=0-255 (A/D) output equates to 0-5vdc
V=N*.0196 (From $42 hack)
%= N/255 * 100.
This gets the % TPS close, but doesn't seem right.

When the Throttle is shut, the TPS actually gives a voltage around .54vdc.
This equals 11% TPS according to the equations above.
This can't be right since the % TPS for Idle threshhold here won't let the ECM control Idle until the TPS is at 1%. (N=3) -
--------------------------------------------
LD5C6: FCB 3 ; 1% TPS FOR CLOSED THROTLE
--------------------------------------------
I can add an offset to my .ads equation, and WinALDL has one too, but what does the ECM do?

Does the ECM use an offset for the TPS to make .54volts = 0%?
If so, where can I find it? I've been searching the hack.

Thanks,
Mike

 

The '7747 auto-zeros the TPS. Each time the TPS value is read from the ADC it is checked against the lowest saved value. If the current read is lower, it then becomes the lowest saved value. This is why the TPS is non-adjustable and the actual voltage at idle is not critical.

So, to get the TPS %, this lowest saved value is subtracted from the current TPS value. The result is then multiplied by a scalar parameter. The result is TPS in %. The scalar parameter (multiplier) is a calibration entry.

So it may be changed/tweaked to get just at 100% TPS when at WOT.

RBob.

 

Excellent. Everything makes so much more sense now. Especially, the last post of the IAC logic Tuning Guidebook article up in the stickies.