3 hours ago, mikey362 said:

edit - @Tech1e if you were thinking about the immobiliser was contemplating having it deleted from the ecu.

 

Nope, merely wondered how you were thinking of getting rev counter, speedo etc. to work

Another question guys.

 

how does the speedo and tachometer operate in the MK1 cluster? I’ve been searching and I can’t seem to find out. Not in my Haynes manuals or online. I’ve not had chance to download the manuals wino has suggested yet either.

 

I know the ECU will take the voltage from the sensors and do what it needs to do but what is the output from the ECU signal for the MK1 dials? Is it a Hz frequency for the speedo and tacho? Or do they operate off a variable voltage idea? 

 

Thanks again 

 

Mike

For the speed the Speedo takes the signal direct from the sensor on the gearbox so that's a pulsed signal, the RPM is via the engine ECU on the CANbus link

 

32-pin plug connection, green 1 - Transponder coil 2 - Main beam 3 - Low beam 4 - Sender for the oil level/temperature (vehicles with WIV) 5 - Speedometer, output 6 - Speedometer, input 7 - Drive CAN databus (low) 8 - Drive CAN databus (high) 9 - Convenience system CAN databus (high) 10 - Convenience system CAN databus (low) 11 - MFD - top function selection 12 - MFD - bottom function selection 13 - Brake light bulb failure 14 - not assigned 15 - Fuel gauge 16 - Low coolant level 17 - Transponder coil 18 - Rear fog light 19 - Fog lights 20 - Belt buckle 21 - Handbrake 22 - Brake fluid level 23 - Oil pressure switch 24 - Wake-up CAN databus (electrical system control unit) 25 - Drive CAN databus (screening) 26 - Convenience CAN databus (screening) 27 - MFD Reset/level 1/2 28 - not assigned 29 - Driving lights bulb failure 30 - Washwater deficit (only for the Elegance vehicles) 31 - Outside temperature 32 - Terminal 31 (sensor)

8-pin plug connection, black 1 - Brake wear 2 - not assigned 3 - not assigned 4 - Parking light on the right 5 - Terminal 15 6 - Parking light on the left 7 - Terminal 30 8 - Terminal 31

 

On early cars, or maybe just non-ABS cars there was a speedometer sensor G22 on the gearbox. That fed straight into the cluster electronics.

You'll not have that sensor on your car though.

 

Now though, I think everything vehicle speed-related is picked up from the ABS wheel speed sensors and the results of the computation sent from the ABS module to the cluster via CAN messaging, as would the engine speed from G28 (crank sensor) via decoding/processing from the engine ECU.

So if you use the existing ABS module, vehicle speed might still be OK, but if the cluster and new engine ECU don't play nicely together you're going to get nowhere, I think, with rpm. 

 

If you want to see if the engine can start/run without the cluster, remove fuses 1 and 16 (IIRC) from the cabin fusebox, and give it a go.

 

 

 

8 minutes ago, Wino said:

On early cars, or maybe just non-ABS cars there was a speedometer sensor G22 on the gearbox. That fed straight into the cluster electronics.

 

 

 

 

 

Mine has ABS but the speedo sensor is on the gearbox.

Are you sure it's not a dummy sensor Lee?

Just now, Wino said:

Are you sure it's not a dummy sensor Lee?

 

No, got wires going to it.

So do the dummies, bizarrely.

Just now, Wino said:

So do the dummies, bizarrely.

 

Oh really? Wow, it might be a dummy then.

Cheers for the quick reply’s guys.

 

@Wino when you say “now though” do you mean 2010 onwards? Or earlier? 

 

I thought mine did have a speed sensor on the gearbox but if dummies also have wires which is probably dumbest thing I’ve herd VW do then maybe not haha 

Nov 2002 on according to a related thread I just found, pics are all dead though, sadly.

https://www.briskoda.net/forums/topic/362340-speed-sensor-location/

 

 

This is exactly the same as mine...

 

Here's a pic of the dummy, with loom connected:

 

2 minutes ago, TMB said:

This is exactly the same as mine...

 

 

That looks like a real one.  Mystery thickens...

 

Your car is post-Nov 2002, right? Comfortably so IIRC.

Edited 21 August, 20196 yr by Wino

Oooh, you learn something every day

 

EDIT: Oh

Edited 21 August, 20196 yr by TMB

3 minutes ago, Wino said:

That looks like a real one.  Mystery thickens...

 

Your car is post-Nov 2002, right? Comfortably so IIRC.

 

Yes, 2003.

I can't see just now where I got that date from. 

Maybe ETKA, I'll have a browse.

Yeah they changed in 2002/3. My Fabia has a manual drive for the speedo that I wired back in after the engine conversion. 

Still can't find that, but on the wiring diagram for a BMD for 2005 this note is double starred off the G22 bit of the cluster circuit

** not valid for vehicles with ABS/ ABS with TCS/ ABS with EDL and TCS/ESP

 

I'll have a look for your 2003 AQW in a sec Lee.

 

 

There it is; for the November 2002 onwards AQW diagram, it has a note for G22: "* not valid for vehicles with ABS/ ABS with EDL and TCS/ ESP"

Maybe your car was manufactured before Nov 2002? but registered on an 03-plate?

Just now, Wino said:

There it is; for the November 2002 onwards AQW diagram, it has a note for G22: "* not valid for vehicles with ABS/ ABS with EDL and TCS/ ESP"

Maybe your car was manufactured before Nov 2002? but registered on an 03-plate?

 

Yeah, possible, Pete. Thanks for looking

This really is the randomest thing I’ve seen from factory. If they couldn’t be bothered to redesign the gearbox when not just put a plug in haha.

 

so my understanding now is that as my MK1 has abs then the signal goes from there to the ECU then back out to the cluster is that via CANBus or not because on the diagrams I’ve got it’s not down as a CANBus wire?

 

@Tech1e how did you go about wiring a manual one back in? Was it particularly difficult? 

Yours will be, as I said, ABS wheel speed sensors telling the ABS module what's occurring. That module will tell the cluster via CAN messaging on the drive CAN bus; I don't see any other way.

I guess the point of the dummy sensor is that the loom needn't change, and it does plug the hole in the box.

Thanks, dunno why I had it in my head the ECU was involved for the speedo lol.

 

Once I’ve got all diagrams I’ll be able to get a better idea but if the cluster won’t play nice with the ECU I can think of a couple of solutions 

- try the cluster and ECU together see what happens 

- figure out what it takes to move the needle for the tacho decoded signal wise and retro fit a decoder that will read the CAN messages and produce the correct signal and wire that into the cluster... much much harder lol 

 

I think that should be everything working on the cluster then.

Edited 21 August, 20196 yr by mikey362
Wrong components

57 minutes ago, mikey362 said:

 

@Tech1e how did you go about wiring a manual one back in? Was it particularly difficult? 

 

No, very simple. I stripped down the wiring from the original loom and transplanted it into the Ibiza loom. Took the blanking cap out of the Ibiza gearbox, dropped the drive in, fitted the transducer and it worked.

Sounds pretty straight forwards certainly something to fall back on 👍

 

I just need to figure out how to over come the tacho. Or rather the best way rather lol