Daugaard

Hi again.
Calibrating the pdk gearbox is still giving me problems after more than 20 attempts. the process stops at 96% every time and the same error comes up P1870 and 65008. I can now see that the values from all four shift rods are ok in neutral, close to zero. But I have no way to see what happens to the values while it performs the calibration.
I have repaired this PDK for the authorized porsche dealer and it is pdk no six that I have repaired for them and the first time it has completely stuck. Tomorrow I'll give it one more try before a brand new gearbox is ordered.
My plan is to remove the back of the gearbox again (boxter luckily) and check my repair that all the wires are positioned correctly. After that, I will hook up PIWIS and see live data while moving the shift rods.
Are there other smart things I should measure while I'm in there? input very welcome.
Thanks
Daugaard

jjrichar

It does seem to indicate from my knowledge there is a consistent error in the distance sensor output. This being the case I'd be surprised if there was a wiring error, but it can't hurt to look. Me personally, I'd be attempting another sensor install prior to a new transmission, as my guess is there is a sensor issue. I'm not making the decision considering all the time that has been spent on the car so take my thoughts with a grain of salt.

Regarding moving the shift rods manually, I've done this extensively in our testing. Some considerations here:

- Ensure you have a hose clamp at the end of each shaft so that parts can't move rearward when you move the shift rods. The upper shaft is not so important, but the lower is essential. If not it's easy to disengage the triple synchromesh on some gears (most likely 1st or 3rd), and getting this back correctly engaged is difficult.

- When you remove the rear casing you will notice you can move each shaft back and forth easily. There seems to be about 2.5mm of movement available. When the rear casing is installed, this movement is eliminated as the shafts are locked into the rear bearings. The problem is that the shafts are sitting in a mid-point position when the rear casing installed, and you need to simulate this mid-point when testing the sensor outputs when you move manually. From my measurements, both shafts will sit 0.8mm back from the full forward position (1.7mm forward of the fully rearward position). So when you move the shift rod, you need to then move each shaft to this correct position prior to getting an accurate indication on PIWIS. The shift rod needs to be fully pushed as far as possible hard against the engaged gear. Sometimes this will in turn move the shaft, so a little playing around might be needed to ensure both the shift rod and shaft are in the correct position prior to taking the measurement.

- You also need to check each indication with the possible pre-selections. eg, checking 2nd indication with 1st or 3rd selected. Ferrous interference at the sensor will have the outputs for 2nd in this case be different depending on the other pre-selection made. I've put a snip of the excel spreadsheet I use for testing below. You can see that 2nd is SR4 retracting, and the possible pre-selections are either none, or 1st (SR 3 retract) or 3rd (SR extend).

Note extension is towards the rear of the transmission, and retraction is towards the bell housing. Disregard all the entries of 13.33mm in the 5th column, as this is just a calculation made by excel based on entries that are currently empty.

- Moving the shift rods manually is easy for the rear two (SR 2 and 3), not so easy for SR 4, and quite difficult for SR1. You can move SR 2 and 3 by hand. SR 4 can be retracted by hand, but SR 4 extension or SR 1 in either direction will require a tool due to it being up the front of the transmission. I used a piece of steel 15mm wide and about 50 cm long with a notch about 0.5mm deep and long right at the end so I could hook it around the shift fork and pull it. To retract SR 1 I just put the end of the tool against the shift fork and gently tapped with a rubber mallet. You need to be very careful where you put the tool on the shift fork so you don't damage the plastic pieces that sit on the ends of the fork and engage with with shift slider. With everything well oiled, the gears move surprisingly easily. Some images below that might help.






Image showing tool I made and where you would place on equivalent position on SR 1 to move it.




Where you put the tool to move SR1





Where you get easiest access to move SR4 on the underside of gearset

Daugaard

Thanks for the input jjrichar.
I finally had time to measure on the boxter again.
No wiring was wrong. and for some reason I forgot to measure the calculated value with preselection.
I had the physical distance and the electronic calculated distance measured via piwis. It seems that the physical travel is 0.2-0.4 mm more than the calculated one and it looks fine. but shift rod 1 sticks out a bit. the physical travel is +8.65 - -8.85 and the calculated one is +7.75 - -8.88.
I then tried to loosen the distance sensor and move it closer to the magnet and the values increased. I took a dremmel and sanded the small guide pin and the bolt hole at the top bolt so that now the sensor sits about 1 mm from the magnet. the forward value of 7.75 increased to 8.43 but the backward value remained -8.88.
I will now try to install the most necessary things on the car and try to carry out the basic setting. later this week and I will let you know.
Daugaard

Wayne Smith

I love the persistence!!! Good luck. Looking forward to a retort of a positive outcome.

jjrichar

Those measurements seem to be very good. The results from our testing show that the movement of a shift rod to engage is 8.6mm, but PIWIS through it's interpretation of the data gives a distance slightly shorter. The 8.88 mm PIWIS distance is simply the PIWIS distance given based on the sensor programming and what to give based on the sensor DF return. So don't read too much into it. As long as it remains below 11.0mm always it should be considered valid by the TCU. This actually corresponds to the duty factor response of more than 10% or less than 90%.

Did you do the testing with the preselections? Your comment seems to indicate you didn't. This from me perspective is a critical part of this testing. You will get significant ferrous interference of the magnetic flux in some channels with the preselections. The OEM sensor isn't susceptible to this, but hall effect sensors are. When doing the cal the TCM seems to measure all of the possible combinations and store these individually. So the response on DS3 with 3rd selected for example by itself might be very different with either 2nd or 4th preselected. Some channels aren't affected much, other much more so.

Unlike the OEM sensor, hall effect sensors are very sensitive to the height of the magnet above the sensor. About 1mm from the sensor face is where the magnet should be, and if not this might affect the outputs significantly, especially with the ferrous interference of preselections. I've never tested a T design sensor, so I don't know how susceptible it is to this interference, but this is what I would be looking closely at prior to closing the transmission and attempting another cal.

BTW, that's a very nice and clean looking workshop.

Prairiedawg

Any updates on this?

Daugaard

Hello. Yes, there is a small update. I have measured all sensor outputs again and this time also with preselection. all values are very fine and they are only minimal influence with preselection. T-design has offered me another sensor, but when the measured values are so good, I think the problem lies elsewhere. I have reassembled the gearbox and it is ready for basic adjustment.
The car is at an authorized Porsche service workshop and the mechanic has all the previous times done the basic setting with piwis and he has not completely followed the recommended instructions as he has not disconnected the battery at any time and he does not think that it can have an influence on the calibration.
I have now disconnected the battery and will not be back at the workshop until week 1 of the new year.
Hope of course it will have an effect with the disconnected battery. It sounds like others have had success with it.
Thank you all for your help and happy new year.
Daugaard

jjrichar

I just knocked out a video on how to replace the distance sensor or speed sensor on the 911 (991 or 987) without removal of the transmission. It's not a video as such, but a collection of images with voice over and instructions etc.

Big thanks to @stjoh for the images and guidance on the procedure. He's of the opinion that it's every bit as easy as the 981/987. No more than a days work. Removal of the transmission is simply not required.

LynxStarAuto

Absolutely! The clone VCI are pure junk, and not worth the headache. I can’t tell you how many bricked ABS modules I’ve had come in from other repair centers, or DIY folks because they are using a clone tool. That’s why I cringe a bit whenever someone calls for assistance, and they tell me they are using a clone tool. I have VW ODIS, and the OEM VCI. I can tell you when programming an ABS module on a VW, the OEM head will step up the voltage to near 30v. The Chiner clones don’t do that. That results in a bricked module. Although I can bring those back on the bench. But it’s more work, and more time needlessly.

As a service professional, I strive to have the OEM tools. The issue with PIWIS is that Porsche doesn’t sell it to you. You have to sign up as a PPN (Porsche Partner Network), and they lease you the tool. You can’t even buy it. The cost of admission is not worth the reward. These cars are fairly reliable, and simple machines. I’ve encountered more complex problems on VW/Audis than on Porsches. Many procedures can be resolved with a licensed tool like Autologic or Iscan, and if there is an issue, those companies have a full suit of employees ready to assist you. Where the clone tool you’re on your own.

Daugaard

Thank you very much for all your help it is much appreciated.
And a final update on the boxter pdk calibration.
After the Christmas holidays I returned to the workshop and reassembled the gearbox and carried out the basic setting, everything went well and the car runs perfectly.
I had changed the distance between the magnets and the sensor a bit. But the workshop had not disconnected the battery between the many unsuccessful attempts to reset. But I had it disconnected over Christmas.
So which of the two things worked I don't know.
But the instruction must be followed strictly.

Prairiedawg

Any updates on the distance sensor development? Still hopefully watching from the cheap seats.

cvalue13

First, I’m new to this forum and Porsche, my first, a 997, only just this morning being delivered to my storage facility (3hrs away) - it hath risen!

This thread is really impressive, both the OP effort and the community.



Second, I happen to be friends with the owner of probably the most advanced aluminum CNC (etc) outfit in the Americas, who with the right files and at least on an Cap/Op-ex basis, could blast out these housings extremely fast and cheap.

He also just happens to be a (modern) Porsche enthusiast - so it’s all the more likely I could approach him in a way to appeal to his crowd-sourcing / community inclinations (rather than him seeing it as a material margin opportunity).


I’d anticipate he might if anything only have a few hesitations about - basically - taking on liability absent offsetting margin rationale.

Just so happens, however, the only thing I’m good for here - as a reformed deal lawyer - is drafting simple agreements that make people feel comfy.





Which is all to say: if this whole concept still has legs, and if pivoting to aluminum housings is an ongoing concern/consideration, there’s at least the possibility of a parts connection I could make here.

Lostpilot28

I sure would be interested in this development, as well.

jjrichar

The project is still going, but delayed a bit due to outside influences. In particular, PV has been under the pump with work commitments (promotion, massive workload, etc) so hasn't had any time to devote to the project lately. Plan to get things going again once the time allows.

cbracerx

Subscribed and sending good vibes to those working to make this happen.