Speedo Cog Drive for VSS Sensor

[SweetBadger 94]

Hi, I’m planning a digi-dash for the new car build (real dash on an android linked to a dta ECU). Going to feed the signal from the gearbox VSS to the ECU and ditch the standard speedo and speedo cable.

 

Just bough a new VSS to replace the standard speedo drive, but the diameter of the shaft on the 1.6 Gti speedo cog is too narrow for the new VSS.

 

Is there a specific type of speedo drive cog for a VSS, or have I been sold a dodgy VSS?

 

Edit: I’d be surprised but are they designed to run with the speedo cog shaft loose? 

Edited April 19, 2020 by SweetBadger

[petert 588]

I’m doing the same and mine takes earlier gears.

[SweetBadger 94]

Balls ok, just to double check is the fit exactly the same as the original speedo drive holder?

 

Do you have a part number? 

 

Also you might be able to save me a bit of time regarding the VSS setup with the ECU. Not much info on them, but I've found a page online that lists them as having 8 pulses per rev, can you confirm? (if this is the case then with a 1.6 red speedo cog the ECU will see just over 9 pulses per axle revolution due to speedo drive gearing).

 

The DTA ecu uses 5v for sensor supply and 5v max input for analogue inputs. The VSS takes a 12v supply (and I assume switches 12v for the pulse). Do you know if you can supply it with 5v, with the signal reducing to 5v instead of 12? If not I'll probably just supply it with 12v and try a simple potential divider to drop the output to a max of 5v but would be good if I could just supply it with 5.

 

Can't believe I threw out a VSS and matching cog not so long ago when clearing out my garage!

 

Thanks.

 

 

[welshpug 1,661]

all the cogs are the same fit, just different tooth count and corresponding colours, even for the ma box,  the drive gear is the difference.

 

maybe yours is spectacularly worn?

[SweetBadger 94]

Ok that's odd, so to be clear the diameter of the metal spindle off the speedo cog has never varied - they are all the same size?

 

It's not worn - it's a good fit in the original speedo drive plastic casing.

 

It's a sloppy fit in the brand new VSS.

[SweetBadger 94]

Original vs new vss below - shows the issue:

 

 

[petert 588]

I'll look at mechanicals later. In the meantime, here's an example (B33) from a 405. I'm not 100% sure it does get 12V on pin 1. Have you measured it? I can't see why 5V would matter in any case. I also read on AussieFrogs that it's 8 pulses per rev. I'll be able to verify that tomorrow hopefully.

Edited April 20, 2020 by petert

[SweetBadger 94]

Thanks that'll be useful info.

 

No haven't measured it, just some googling brought up the following in reference to a Gti6 VSS

 

12v pin 1 (from double relay), 2 = gnd, 3 = signal.

 

 

[petert 588]

My VSS is identical to the standard BE1/BE3 speedo drive in terms of dimensions. Identification, as per pics:

 

EATON

PA66-GF30

21D7

 

Googling, I found this in Argentina. Are you guys talking with them yet?
https://articulo.mercadolibre.com.ar/MLA-615406626-sensor-captor-velocimetro-eaton-original-peugeot-106-15-d-_JM?quantity=1

 

Edited April 20, 2020 by petert

[petert 588]

It seems the PSA part number is 6160.24 or 6160.70

[SweetBadger 94]

Hi thanks for confirming,must mean that the diameter of the spindle has changed at some point. Will return the VSS I bought.

 

Interesting that the diagram with the PSA part shows the VSS with the combined speedo cable drive too.

 

6160.24 brings up lots of options with the combined speedo cable drive.

6160.70 seems to the electrical output only version

 

edit: this Valeo part (255304) matches 6160.70, and looks like the same design as the one you have.

 

https://www.ebay.co.uk/itm/VALEO-255304-SENSOR-SPEED/222747846350?epid=24012958582&hash=item33dcce66ce:g:qlAAAOSwN~debj50

Edited April 20, 2020 by SweetBadger

[SRDT 182]

8 pulses per rev, 5 pulses per meter with the Hall sensor.

There is also a 2 way connector sensor but you need the infamous speed interface module to convert the signal to a proper square wave;

 

[SweetBadger 94]

Hi that's great thanks for the info, and for the highly educational Peugeot video! 

 

There are a hell of a lot of electrical components to go wrong with that 406!

[SweetBadger 94]

Ok, Valeo part arrived today, it fits! So can confirm that Valeo 255304 is the right part for a 205.

 

I tried measuring the VSS output powered by both 12v and 5v. Was quite surprised with the signal levels my volt meter saw.

 

Supplied with 12v, the signal pulse went from 0 to 2mV 

 

 

Supplied from 5v, the signal went from 0 - 1.9mV

 

 

So it would appear that supplying the sensor with 5v instead of 12v has very little effect on the signal output.

 

The low signal level measured concerns me though. It may be that my crappy old meter has a high enough input impedance to affect the signal voltage but I doubt it. @petert would be good to see what you measure from your sensor to compare. Hope the sensor I have isn’t faulty!

 

If that’s the signal level the ECU sees, then I might have to stick an op-amp circuit in there to amplify the signal voltage for the DTA.

 

I can also confirm that there are 8 pulses per revolution.

 

 

[SweetBadger 94]

Actually if the VSS is switching to ground, then I might need to add an appropriate pull-up resistor - will try adding 5k pull-up resistor tomorrow.

[petert 588]

Nice effort. I'll rig up something similar today.

[SweetBadger 94]

Confirmed - a 4.7k pull up resistor worked with a 5v supply.

 

connect it between the supply and the signal pin, and the VSS signal switches between 5v and gnd.

 

[SweetBadger 94]

Got the additional wiring added into the engine loom last night.

 

One issue with the VSS sensor is it has a non-standard JPT connector. There's an extra slot, presumably to stop the wrong plug being connected.

 

 

Worst case I'll just remove the extra key on the VSS, but before I do that anyone know if these plugs are available?

 

Thanks.

 

[Silvermetis 6]

I am building an electric power steering column for a 1.6 205 Gti and was planning to use a 3 way connector 616024 to provide the speed sensing pulse. 

 

I need 15 pulses per metre (24/rev) for correcting mapping has anyone taken one of the connectors apart to see if it is possible to modify them.

 

I presume the units use a hall effect sensor and was thinking of fitting 2 additional sensors positioned at multiples of 15 degrees around the rotor. 

 

I would be grateful for any advice.

[Daniel306 12 1 Cars]

How accurate are these sensors? Iv got a Sagem sensor connected to the emerald ecu for gear adjust boost, at low speeds it appears to work fine but at higher the raw speed displayed by the ecu jumps between 15mph and 70mph,

[SRDT 182]

If the sensor isn't faulty then it must be something like the ECU that is filtering too much or can't see pulses that are too close.

The sensor must be accurate, you don't have this problem on a stock car, but the signal is probably hard to read for the ECU.

Ask emerad about it, you're probably not the first one to have this problem and if you are start by trying another sensor.

[jackherer 543]

I had a similar problem using a Sagem sensor connected to a Stack dash. I had to use a Stack ST492 pulse amplifier.

 

Your best bet is to ask Emerald because they know what their ECU needs to see from a sensor.

[welshpug 1,661]

12 hours ago, Daniel306 said:

How accurate are these sensors?

its an oem sensor fitted to millions of vehicles, I would imagine they are pretty decent, unless you have a cheap chinese knockoff, or voltage supply issues