Long shot but here goes, I'm sure I read somewhere on here that the left hand drive models that had a fuel consumption multi display computer thing have an electronic hall sender built into the back of the speedo head which from where the vehicle speed is derived??

I've tried the search function but I can't find a reference to it now.. Anybody know?

You mean this one below. What exactly do you have in mind?

 

I need a vss signal to send into the ecu on the 1.8t car.

is that speedo different to the normal ones or does that Hall effect switch just screw on? Do you know how many pulses per revolution that hall sensor makes?

Here it is.how to build your VSS.
You have to use a TLE4905L Hall sensor (PG-SSO-3-2 package) mounted on a small PCB according to photos below.


 
The speedometer is the original one without any modification. See Hall sensor PCB mounting details below.



The output of Hall sensor is connected to ECU via a simple interface shown below. R1 pulls up the signal line, C1 acts as a low-pass filter, and C2 filters the +5V power line.

I can't offer first hand info on the following::

- if there is a slotted disk inside speedometer capable to interact with the Hall sensor (it should be, but I never opened the speedometer)

- what is the frequency of pulses according to speed (I would like to know too)

Edited 17 October, 201312 yr by adurer

I shall obtain a spare instrument cluster to take apart methinks.

Don't forget to take photos while taking it apart.

When I was looking into the trip computer Tom I found that it was a bolt-on sensor to fit the normal speedo so should be able to retro-fit something.

 

Phil

When I was looking into the trip computer Tom I found that it was a bolt-on sensor to fit the normal speedo so should be able to retro-fit something.

Phil, did you feel my reply is not trustworthy or invisible? Because the "I found that it was a bolt-on sensor to fit the normal speedo" part was covered in my first reply (not just in words, but in a photo showing the original TC-6 speed sensor), while the "should be able to retro-fit something" part was also covered in my second reply with schematic and photos. So what else is new?

Phil, did you feel my reply is not trustworthy or invisible? Because the "I found that it was a bolt-on sensor to fit the normal speedo" part was covered in my first reply (not just in words, but in a photo showing the original TC-6 speed sensor), while the "should be able to retro-fit something" part was also covered in my second reply with schematic and photos. So what else is new?

 

Alright! Chill! I was just backing up what you had said.

OK, we're cool. But it would have been much direct something like "I subscribe to everything adurer (btw it's Richard in real life) said, also I can add that..." Everybody should learn to trust my opinion, I have only a genuine desire to help other people by sharing my knowledge. I happen to know a lot about TC-6(P) onboard computer in particular and carputers in general so that I'm positive Tom will be able to match this VSS to his bomb engine.

hold on to your hats everbody..

 

i appreciate the good quality replies from all, i've never seen one of these tc6 things before, i've done a bit of digging and by all accounts it appears it was a retro-fitted kit that came from a czech manufacturer call apri and it's long since obsolete now, they no longer make them or carry spare parts for them

 

i did dig up an old thread that mentioned it here http://www.briskoda.net/forums/topic/116341-on-board-computer-felicia/ which was in 2008, like i said before, i was certain i had read it here but couldnt remember if it was a genuine skoda part or aftermarket..

 

i'll have no problem knocking up that circuit on a piece of veroboard (strip board), it doesnt have to be pretty. i've picked up a second hand instrument cluster from the breakers yard today so i can strip it and have a play with it in due course..

 

for the vss function to operate corretly on the bosch motronic ecu on the 20v engine i need 16 pulse per revolution of the speedo cable i believe (need to confirm this), if there is no trigger suitable i will glue some tiny magnets onto the outside of the wheel

for the vss function to operate corretly on the bosch motronic ecu on the 20v engine i need 16 pulse per revolution of the speedo cable i believe (need to confirm this), if there is no trigger suitable i will glue some tiny magnets onto the outside of the wheel

That 16 Hz signal... should correspond to what speed?

sorry not 16hz... 16 pulses per revolution of the speedo cable i believe, i'm sure that's what the mk4 golf gearbox speedo senders produce, so so the GM ones too, but i need to cofirm this before doing anything really

I am particularly interested in seeing the guts of Felicia speedometer. I think that people who had issues with not working speedometer or odometer would like to know how to get inside it too. 
 
If you need smart magnets, check this out. They even make magnetic tapes. Now... where could you stick 16 of those very light stripes?

I haven't looked into it yet, I've been trying to resolve a few other non related issues today.

I think I might have some tiny magnets left over fom a previous project, but I do like the idea of magnetic tape, that's given me another idea for another project.

Here it is.how to build your VSS.

You have to use a TLE4905L Hall sensor (PG-SSO-3-2 package) mounted on a small PCB according to photos below.

 

The speedometer is the original one without any modification. See Hall sensor PCB mounting details below.

The output of Hall sensor is connected to ECU via a simple interface shown below. R1 pulls up the signal line, C1 acts as a low-pass filter, and C2 filters the +5V power line.

I can't offer first hand info on the following::

- if there is a slotted disk inside speedometer capable to interact with the Hall sensor (it should be, but I never opened the speedometer)

- what is the frequency of pulses according to speed (I would like to know too)

Hi Adurer, Could you please re-share these missing images in your post again, Thanks.

Edited 9 April, 201610 yr by moatz