Shift strategy idea

[907DAVE]

Shifting is determined by comparing speed and throttle position. Throttle position is measured using a/d counts. Cody had a nice little layout on a/d counts vs volts, I will have to see if I can find it.

[907DAVE]

Here it is......

Just for your information:

A/D counts are a more precise way of measuring the 0-5 volt input to the PCM from the Accelerator Pedal Position (APP) sensor. There are 204 A/D counts per volt of input.

Keep in mind that the APP sensor DOES NOT put out 0 volts, nor does it go all the way to 5 volts. This means that you will never get 0 A/D counts or a full 1023 A/D counts. More like 100 to 918 A/D counts.

For those of you who have this "updated" MFD scale, you might want to take this into account on your MFD map.

[GTS]

Thanks for the info! So what are A/D counts? What does A/D stand for?

Maybe this is a question for a different thread being it's a little off topic but at what point of APP does 100% mass fuel desired come in at? And is there a reason other than the throttle pedal won't push the sensor far enough that it won't hit a full 5v?

The reason I ask is because I trimmed the stop down a bit awhile back to get the voltage close to 5V. The problem that I ran into was that if I pushed real hard it would shut the engine down so I assume once it hit that full 5V it was to much and the PCM cut fuel. I thought about just putting a 5V regulator on it so that it would come up to 5V and not go over. This way I could get full load fuel and not have to worry about it shutting down. Is my thought process on this off?

[907DAVE]

Originally Posted by GTS

Thanks for the info! So what are A/D counts? What does A/D stand for?

Maybe this is a question for a different thread being it's a little off topic but at what point of APP does 100% mass fuel desired come in at? And is there a reason other than the throttle pedal won't push the sensor far enough that it won't hit a full 5v?

The reason I ask is because I trimmed the stop down a bit awhile back to get the voltage close to 5V. The problem that I ran into was that if I pushed real hard it would shut the engine down so I assume once it hit that full 5V it was to much and the PCM cut fuel. I thought about just putting a 5V regulator on it so that it would come up to 5V and not go over. This way I could get full load fuel and not have to worry about it shutting down. Is my thought process on this off?

A/D counts is basically a signal that has been converted from 0-5 volts to a digital signal 0-1024 A/D.

Here is some good reading on the subject.....

http://forum.gopowerhungry.com/minot...0-scaling.html

http://forum.gopowerhungry.com/minot...-question.html

[Power Hungry]

A/D stands for Analog to Digital. The means that the 0 to 5 volt "analog" value is converted to a "digital" number that the PCM can use for processing. The A/D Converter in the PCM is a 10 bit converter which means that it has 1024 (2 to the 10th power) steps on the scale. Since the analog voltage scale is 0 to 5 volts, 0 volts = 0 A/D Counts (or "ticks" as Ford refers to them) and 5 volts = 1023 A/D Counts.

As to the "shutoff" error with excessive APP, this is because the maximum allowable APP is 922 A/D Counts, or roughly 4.5 volts. Anything about that is considered a pedal fault and the ECM instantly drops the engine to idle to prevent an accident or a runaway engine. At that point, you MUST drop the APP voltage back to an idle value and reset the IVS before the throttle will function again. This value can be raised in the parameters, but I've never found any reason to unless the throttle pedal has been modified.

Hope this helps.

[GTS]

Thanks for the info Bill. So if I'm not getting full MFD and only hitting 3.8V of throttle pedal input would it be better to modify the Inferred Throttle Position table to deliver full MFD or to mofify the throttle position sensor so that it will read a full 4.5v?

[Power Hungry]

Whatever you do, you'll have to match your inferred table to the output voltage of your sensor. If the sensor only reads 3.8v at WOT, then the table should reflect that. If it's reading 4.4v at WOT, it should again reflect that. This way you can make the most use out of your pedal travel.

[GTS]

Thanks Bill. That's kind of what I was thinking.