In recent tuning efforts for overall drivability, investigations concerning ZF shift patterns and the overall ECM performance, some very predictable and desired results came about while working with TPS settings. Many are unaware of the relationship of some engine components and it's overall impact on other systems. TPS is one of these items.

By rotating TPS 1~2 degrees counterclockwise (that's about 1/3 to 1/2 the screw width) eliminated the harsh shift patterns, early downshift on decel, lowered elevated throttle line pressure. It makes a great difference. After each change, you will need to disconnect the battery and use relearn procedures, but you do not need to reset ZF adaptions.

 

Drive-by-wire throttle body or the older cable type?

 

It's a X350/AJ33 N/A. No cables.

 

How many dive cycles or Miles have you done on that change?
I would expect the ECU to learn the new TPS position and negate any change

After resetting the ecu you will be using the stored values will it get to the P1001 (drive cycles completed).
My guess is you new position is closer to the stored value so its better on you car after a reset.

Cheers
34by151

 

The answer to your first question, is that after you disconnect the battery, you have to go through a set of things. One of those is you depress slowly the accel pedal to full throttle, hold 5 seconds, rinse and repeat 2 more times with ignition is run position. Start the engine. Let idle for 10 minutes. Place in drive and hold still for 2 minutes. Drive it at least 5 minutes...

Every auto using modern automatic transmissions has to perform some very specific functions. Throttle pressure is one of those. Either you do it with a cable, or a solenoid. The latter comes with it's own trappings. In the X350, Bosch's Mechatronic uses TPS for it's calculations. Moving the TPS is almost analogous to adjusting the throttle pressure cable. Effect is the same. Pre-warning... a little doesn't make a lot better when it comes to moving TPS too far. But the feeling of silk-soft shifting can be had. You can tell you are at the respective "sweet spot" when it starts driving like an electric motor. When you hit that, stop adjusting.

 

So you have not completed the drive cycles yet just confirmed its in rang for calibration

Granted the TPS needs to be within a range when you setup
If it is not it would generate a fault

As long as you are within the limits you can start and calibrate/learn the actual position

What I cant see is making a slight change would have any effect on the ECU or TCU after the calibration

If you did not reset the ECU, yes but the change would have to be very small and I would expect the ECU to learn the change and cancel it out over time anyway

I can see you would have an effect if the system was mechanical and not drive by wire. In this case using a change to fool the ECU but with our DBW system I cant see it.

The ECU will see the same throttle position regardless, that's way the calibration is for

Cheers
34by151

 

The proof is in the driving. Nuff said. Well over 1,000 miles since the change.

 

Placebo effect

Most would say a bigger exhaust is better performing too but a dyno and track times say at best no change

Cheers
34by151

 

Now that is amazing. Placebo affect? If you want to be rude, go try it with someone else. Go prove me wrong. Go get yourself some 5 sided Torx bits and try it for yourself, and then come spout about your placebo. See, the obvious difference here is that you prove you haven't even tried it, you're speaking out of ignorance, with someone who has actually taken a bit of time to work with this issue. Have a great day.

 

Sorry you took offence it was not my intention

What you are saying is not consistent Jag Training re with to how the ECU operates in terms of learning and calibration.
I can't see how this can be explained and you don't seem to offer any reason.

As I have stated, I can accept your results if your system was out of or close to out of calibration in the first place.

There are 2 components that have an input in this the TPS and the APP and to quote the "Jag Engine Management and Diagnostics training" manual

"The APP Sensor signals are checked for range and plausibility. Should one sensor fail, the other is used as a ‘limp-home’ input. In limp-home mode due to an APP signal failure, the ECM will limit maximum engine speed to 2000 rpm. If both signals have a fault, the ECM adopts a fixed high
idle speed of approximately 1200 rpm."

"Throttle position is regulated via an electronic throttle body (‘drive-by-wire’ system) in response to driver demand as sensed by the APP Sensor. A Throttle Position (TP) Sensor is mounted in the integrated cover plate on
the throttle body assembly"

"A software strategy within the ECM enables the throttle position to be calibrated at each ignition cycle. When the ignition is turned ON, the ECM commands the throttle to open and close fully, thus performing a self-test and calibration, learning the position of the full closed hard
stop position."

Cheers
34by151

 

On the very similar drive-by-wire S-Type throttle there are 2 TPS sensors (just as there are 2 APP sensors), used for safety. I would strongly recommend NOT messing with the high-precision throttle body. The PCM will learn what the sensors are & do (APP and TPS sensors, all 4 of them). (BTW, they're all shown in the circuit diagrams.)

At best I think you'd get some short term "fix", at worst you'll ruin a good throttle body.

 

Well, you would first have to explain to me how you can "ruin" a good throttle body. And I find you too, not speaking from actual experience but your "best guess." The Denso system used is not new to the industry. Obviously your assessment isn't based on fact, but by simply your speculation. I hope you have a great day though..

Mechatronic - For shift point management alone the TCM requires an OSS sensor, throttle pedal position, brake pedal status and gear selector position.

The base voltage reading, taken from the TPS by the TCM sets the base curve for throttle pressure. And a voltage decrease from nearly 0.8v to closer to 0.55v on pin 2 makes a difference. The ECM will take care of itself when you do a span slowly with the pedal inside the car.

 

Mmhh, am not so sure about it all.

1st of all the ECU learns what the closing point is (so actual voltage from the TPS) when you turn the ignition on by closing the butterfly. That gives then the starting point to know where 100% opening would be (as it knows how much voltage steps are needed to go to a 90 degree butterfly opening). The starting point should also be within a certain range, but I don't have those details.

The TCM would probably get the throttle opening % from the ECU which it calculates, which it uses for its strategy. If the TCM would go by TPS signals, it would not know the actual throttle % opening obviously, as that can vary pending on where it is calibrated to (by closing the butterfly procedure as mentioned), so imo it would be a flaw if this is the case (maybe even an accepted one, who knows).

I trust you have noted a difference, but as these transmissions are adaptive based on so many parameters, the change you notice now maybe just because of the steps you took, and the way of driving afterwards.

 

+1 for Avo's and JagV8's comments

Box, you seen to be upset by any comment that questions you. Nobody is trying to do that to you. Rather we are asking for more detail

Please confirm if you adjusted the TPS (on the throttle body) or the APP (on the pedal) Your posts indicate you adjusted the TPS

Assuming it was the TPS the ECU does a self-test and calibration, learning the position of the full closed hard stop position every time the ignition is activated.

So moving the position can NOT alter the signal

You could alter the APP signal but this again is learned and will be canceled out

The TCM is adaptive and will learn any new settings change
From what you posted it is clear you did not reset the TCM adaptations

So unless you corrected a problem and did not realise it the TCM still has the adaptations prior to any changes and will learn its way back

I wish you lots of luck with your changes

Cheers
34by151

 

DVOM argues that with you 34by151. Still yet to even try it yourself I see... Keep telling whatever you wish, my vehicle works just fine, and I love the way it shifts now... Have a great day...

 

Box, please dont get aggressive and if you can it would be good to answer the questions put to you.

You don't seem to understand how the ECU operates in relation to the TPS.
The DVOM reading at the sensor is NOT the throttle position it is merely the sensor position

When the ign is enabled the ECU commands the TB motor to cycle the TB fully open and fully closed. This happens every time you turn on the Ign.
The ECU stores these values and then calculates the throttle position in relation to these positions. This is the data the is fed to other modules
(like the TCM) as the Throttle Position

So if you alter the sensor position, yes the signal will change and no the throttle position will not. It is this calculated position that the ECU feeds to other modules not the voltage at the pin

I have no doubt you believe it is shifting better but that is probably a result of either resetting adaptions or something else you did along the way and did not notice.

Cheers
34by151

 

You just can't ask some people let alone tell them, especially when they assume that they know what they're talking about and allege that others - no matter their experience and knowledge - do not.

 

We have:

The actual carbon tracks within the TPS cover about 300 degrees.

The whole purpose of the calibration is to account for setting error,
wear, and factory tolerances.

And ...

The TPS is a feedback device meant to inform the ECU that the blade has in
fact been positioned to the commanded angle.

Other than the ECU needing confirmation that the throttle blade is operating
properly, the TPS serves no purpose.

++

 

I'm curious, which X350 and 6HP26 did you test this theory on? Don't you own a X308?

 

Come along children-play nice~ This can be easily settled- the inputs and outputs from the Jaguar transmission are shown in fig.04.1 Jaguar XJ Electrical Guide. I have had a quick look and cannot see any direct input to the transmission control unit from the TPS.


However I should point out that I am very old and may not be able to see it. Also I am laying a hard wood floor and can't spend anymore time looking!