In the interest of a broader understanding, the following post by
BOX probably has at least some bearing on the perceived improvement:

https://www.jaguarforums.com/forum/x...e-body-145320/

So, the sequence is:

a) install new valve body around June 27
b) install fresh ATF, likely around June 27
c) clear TCM adaptations, likely around June 27
d) fiddle with TPS, around July 9

Between June 27 and July 9, the vehicle has likely been
driven a few miles circulating the fresh ATF and
adapting the TCM during those miles.

Adapting the TCM is of course intended and documented
by the manufacturer as leading to shift improvements.


It has also been observed many times on JF that a ZF 6HP26
that is shifting poorly can improve immensely by changing
the ATF one or more times. But, the vehicle has to accumulate
some miles for the improvement to kick-in. None of the reports
mention fiddling with the TPS. (count Grant Francis amongst
the proponents of this type of result).

Considering the TPS without also considering the new valve
body and fresh ATF is just bad science.

Case closed.

++

 

Don't need to.

See post just above this one.

BTW, it is a logical fallacy to declare known facts
as theory.

 

It's also a logical fallacy to claim authoritative knowledge by your own reasoning, without empirical data. The vehicle responds the way it responds, regardless of your assertions it does not. You don't own one, so your assertions about how it responds is purely speculation. You have no idea what you are asserting. While I appreciate you wanting to contribute, what you are and have asserted doesn't show itself as valid data, or the way the vehicle actually responds, in light of your assertions. Same invite is presented to you, go get one and try it and then come talk. Have a great day.

 

You mean: YOUR car has done what you say (well, you claim that to be so). Given the sequence of changes and events you've apparently done then effectively your claims about TPS are at best suspect and, bearing in mind people who know how these work in conjunction with the PCM, your claim's more likely wrong.

If you're happy, fine. I recommend others do NOT take your claim(s) as truth.

You won't go far wrong thinking of the throttle as a closed loop control system with redundancy, just as the engine mostly operates as a closed loop system (though with hardly any redundancy). The TCM & PCM mainly cooperate via CAN. So if the TCM needs to now about throttle it gets the data via CAN from the PCM.

If you tweak the throttle body in any way that the PCM doesn't know about, the PCM will use its old learned values, get the fuelling marginally wrong, see it's wrong from the feedback of the O2 sensors, adjust its values, and go forwards in time using values that have compensated for your tweak. This is the same process it uses all the time for every engine characteristic that it has to learn and relearn with age and wear. (This is "modern" (*) engine 101.)

(*) started from about 1985, so not really modern

 

JagV8, you're right. I have a one-off vehicle, that no one else on the planet has. It defies all logic, and the placebo has taken over. I now know why Jaguar used security screws.

Truth is JagV8, it is what it is friend. Either have the common courtesy to have either confirmed this, (as it is very predictable and repeatable) or simply say you don't know. That's a better position to take.

 

Box, We have no doubt you believe what you are saying but it is counter to how the ECU operates.

Going back you said the TCM adaptions were not reset but the ECU was.
However as plums noted you posted earlier that the fluid and valve body was changed and the adaptions reset approx 9 days earlier.

This is the most likely reason for your result given the info you have posted and is a result of the TCM learning. The initial learning stage takes 100+ miles to complete.

I concur with JagV8 on this

So in your own words
If you would like to discuss and work out the reason for your improvement then we are all happy to do so but you will need to offer up more information

Otherwise
Cheers
34by151

 

I have pointed out:

a) common knowledge on these boards as to the effect of the prior
actions which explain the improvement in shift quality

b) the method and physical characteristics which a Denso TPS is known
to operate under and possess as used by Jaguar, derived from both
prior knowledge and a huge thread a few years ago when multiple
TPS were dissected and measured

Apparently while this is not enough, the OP is not bringing up
anything to explain his magical TPS fiddling other than to say
because he says so.

This in total denial of what other experienced and knowledgeable
members have to say.

Apparently, the takeaway is that anyone disagreeing that such a
magical TPS exists is an idiot to be summarily dismissed.

Hopefully, future readers will have the wherewithal to look around
before leaping.

++

 

Topic closed and pm's set