Mustang TPS Adjustment - 0.999999v not necessary

[Noobz347]

The [only] difference is that you'll have the most TPS resolution the closer you are to the top without going over. Going over = dead space and a flat spot at the top of the TPS range. .99 or lower will get chopped up into reference intervals by the EEC at startup. The closer you are to the top the fewer intervals will exist. The difference between intervals at .99V and say, .80 volts is [not] 10%. It's considerably less.

If I remember correctly, you might squeak out one additional interval toward the top of the scale. The scale itself is curved. There are fewer reference points at the top than there are at the bottom (for mechanical reasons, however, who needs max resolution at WOT? The EEC has reverted to that table way before you got the throttle fully opened).

 

[Mustang5L5]

Here's some snips of the GUFB logic. This pertains to the A9L specifically but others should be similar. This is a 600-page document, so i can't post ever snip of the logic. Just going to post some highlights. Some of these might be blurry and requiring clicking on the photo to bring up a clear view

Definitions

Logic. This can get pretty messy as variable upon variable begins to stack on top of the RATCH value as different offsets are added.

 

[Mustang5L5]

Here's a breakdown of the ECU code dump logic.

And here's more logic that shows that the ECU does not need an absolute TPS value to proceed. A range is expected and accounted for in the programming.

 

[AeroCoupe]

Very informative and thank you. I will say my brain does not process code unless its in ladder logic but the above once again disproves the setting the closed throttle TPS voltage as close to 0.99V as you can.

So if you were to set the closed throttle TPS voltage I would think that 0.85V would be a good number to shoot for. I only say that is its kinda in the middle of the acceptable range so it would account for any degradation in wiring or sensor accuracy. I haven't looked at mine in years but I think the last time I set it I did 0.95V or so per the tuner's request. Have not replaced or moved it since and have zero issues so I doubt I will bother getting the DVM out.

Again, good info man!

 

[Mustang5L5]

Yup. There's absolutely nothing wrong with setting your TPS voltage to some value in the middle of this range. But what we want to move away from is the thought that: "My car is running funny and my TPS voltage is 0.91 volts. Maybe i should bump it to 0.99?" That's really what we need to get away from.


There was some additional logic in there that DOES state how if the MAF is defective, the ECU will switch to a TP logic, but really in that sort of scenario you should be fixing the vehicle issues and not trying to tune for throttle position logic.