TDI annoying pause when pulling away

[hotpod]

1997 AHU ETDI
The question is: When I first pull away in the van, it starts moving then has an annoying momentary drop in revs after which it is fine.
Pulling away from my driveway, on a bend, if I have forgotten to rev it thoroughly before I try to pull away, I make a very ungainly and sometimes dangerous lurch then pause.
I am pretty sure this has something to do with the 6 or so wires, still in my engine bay which are for the 2x brake and 1 clutch switch from the golf. The original plan was to put another multi core cable to the front and try to nicely mount the switches at the pedals, then I started reading about putting a switch on the clutch slave cylinder banjo and using the brake light wiring in the engine bay.
That is fairly high on my list of priorities but there are so many other jobs in the queue ahead like finally sorting out a chargecooler. Plus its not currently a big deal, just annoying a couple of times a day.

The three switches are also in the engine bay tucked out of the way and connected to their respective wires. My thinking was that I could maybe tape them up in their pressed state and that might do the trick but it hasn't and I cant work out if the ecu is expecting them to be pressed or depressed to pull away nicely. It has been like that since 2014 I think 
Is there a way to join or not join the three pairs temporarily to stop the ecu from pausing on takeoff?
Or am I barking up the wrong tree entirely?
I have the golf wiring diagrams, and the testing data for the switches but am struggling to guess what combo the ECU is looking for.

 

[syncroandy]

No.
Yes.

[hotpod]

There's no way to join them and I am barking up the wrong tree?

[hotpod]

On Sunday, I fitted the Brickwerks resistor and deleted the remainder of the EGR vacuum stuff, fitted the original red blue and black 3.5mm pipes to the shiny new n75 valve for the wastegate control (now have boost everywhere I go unless I go over 15psi ish which then trips limp mode so presume it is either a wastegate problem or because I dont yet have a Charge cooler, the hotter temps are somehow pushing the expected intake pressure outside the range that the ECU is expecting?) and finally worked out how to wire the alternator W terminal to my rev counter which finally works which is awesome.
I also decided to remove the 3 switches from their cable tied to the loom position in the engine bay and connected each pair together with small connectors and tucked them away inside the black junction box.
I started the truck, pulled away with out revving and shot off the driveway with no hesitation. Awesome.
Awesome for about 1 mile at which point I had, and this is the first time I have noticed it, a flashing glow plug light.
I was fairly sure this was related to the brake switch wiring so carried on to where I was headed and hooked up vcds once I arrived.
I had the usual manifold pressure related fault and the vehicle speed not making sense faults and one about the immobiliser ( trying to start without the secret key in place) but those dont usually give me the warning light flashing. I now had a new one about the signal from the brakes being implausible. I presume that the the ECU doesn't think you can do 60 with the brakes on?
I have two wires for the clutch switch, two wires for one of the brake switches and only one wire for the other so I unjoined the brake pair and cleared the fault codes and it is no longer an issue but...it now hesitates on first pull away again.
I'm reading a lot about this so I am beginning to understand a bit more. I think the brake switch that I just have one wire for is just for the brake light and the other one is for the cruise control? as I presume the clutch one is also?

Having just written all of that, it has just occurred to me that the cruise control might be active in the ECU.
I shall go try to turn it off ( until I need it, but that a long way down the priority list)
 

[hotpod]

Nope, it was not active anyway.
I activated it and still have the annoying pause.
From the fact that it was the S13-2 cruise control switch that I had to separate, and that I had no engine hesitation when they were connected suggests that the ECU needs to see them connected initially and then disconnected. as the switch is naturally closed connection that means that the ECU is expecting the brake pedal to be pressed initially (contacts closed) and then released (contacts open) .
It looks like that switch is connecting and disconnecting an earth signal so I somehow need to get the brake light at the rear to trigger a relay to break an earth connection to pin 20 on the ECU.
I have a lot of relays.


 

[hotpod]

Sorted I think.
I had a very complex test setup with a separate relay for brake 2 and clutch and was initially ignoring brake 1.
I took a feed from the rear brake light at the rear lamp connector temporarily and an earth from the side of the engine bay and got the relays working but still had the pause. A bit more thinking suggested that the brake 1 wire ( there was only one) was expecting 12v when the the pedal was pressed so connected it to the brake light signal which energised the relay and no rev hesitation and no fault codes.
I then realised that the ECU had been originally ignoring the signal from the clutch pedal so guess that is only for the cruise control so just joined them back together and continued with jut the one relay for brake two and took the brake light feed and earth from the cylindrical front to rear light loom connecter in the black junction box and the relay fits nicely in there too so its all dry and out of the way.
Turned cruise control off again and checked that VCDS was seeing brake operation, and now it's all tidy and works finally.
I am waiting for an M10x1.0 tap to arrive and will fit a brake light switch to the head of the clutch slave banjo bolt as soon as it does and then wire the clutch wires to that and then start thinking about sorting out cruise control.
 

[hotpod]

Scratch that!
I misunderstood the open/closed relay meanings on the wiring diagrams and I need a changeover relay to break the circuit on the for F47 and F36. Which means that I will need a separate relay for the clutch if I go with my brake light switch on the banjo bolt. That will have to signal another relay. I found two micro relays on ebay with harness' which I will fit when they arrive but in the meantime found a slightly odd but functional changeover relay from either a kombi or a golf but it is doing the job with feed from the brake light and a separate earth and I realised that the second wire on both the F47 and F36 is just an earth so I have ignored that wire because whatever relay I found connects to the earth used to trigger the relay when it switches.
I have not test driven it yet but I have no rev hesitation.

I realised that the measuring block for cruise control shows whether or not there is a signal for all 3 switches in one box which shows 3 zeros or 1's which change it the signal switches. it shows them as F/F47/F36
in my photo I am not pressing the pedal and it reads 000. When I press the pedal it reads 011
So the two which are changing according to that are the cruise control brake and the clutch but I'm fairly certain that the clutch is doing nothing which suggests that either I've got it wrong again or they are mislabelled 




 

[hotpod]

Well the changeover relay did the trick it seems. No hesitation and no fault codes so the ECU is seeing feasible signals from the brake switches and happy to ignore the fact that I'm apparently not using the clutch.
When the new relays and the m10x 1.0 taps have arrived and I get a dry afternoon spare I will try to wire all three switches properly enough to start to think about my cruise control and then I will do a write up I think because I have yet to find all the info on this in one place and certainly not a decent how-to.
Unless someone knows where such a write up is, in which case, please can you link it here 

The bonus of all this ( and the limp mode boost issue I've had for years ) is that the van is running better and better and the engine bay and loom are getting tidier and more sorted by the day. Plus my understanding of all these things is improving. Hoorah.
And I have BOOST!

[hotpod]

OOP.
I just found an old post of yours Syncroandy.

It shows how to wire the relay properly and I noticed this...
'Sender earth' -> ECU Sender earth input (not chassis earth) - commonly Brown/Blue
It was a post about LED bulbs and the F47 signal

I shall remedy that as soon as the proper relays arrive.
Thank you

[syncroandy]