Vehicle Speed Sensor (VSS)

Hi all, those of you with Subaru EFI, how are you all deriving the VSS signal required by the Subaru ECU/ECM?
I've read a few posts elsewhere saying that the Subaru vehicle speed sensor can be replaced by a hall sensor circuit and some magnets mounted to the drive shaft or other part that rotates when the vehicle is moving. Has anyone got a circuit diagram for this hall sensor circuit?
Any info, pictures or advise would be greatly appreciated!

Yoyu can machine up aring that bolts onto your CV Flange, mount magnets on it and it will act like the VSS. Geoff at K3 Auto Electrics in teh Valley told me all about it. Talk to him, he is a very very handy guy to know when it comes to wiring weird and wacky engines.

I don't have experience with the subaru VSS, but I do with my Mazda one.

The front cut I bought had two speed sensor, piggy-backed on top of each other. One was for the ECU, and the other one was for the 4 wheel steering.

I have only used the ECU one. I got both sensors with my front cut, so I just connected the VSS to my VW speedo cable, and kept the 4WS one as a spare.

This had the added advantage of letting me run the Mazda instrument cluster. The only prob was the speedo needed recalibrating, as the factory VSS run through internal gearing in the gearbox (21:25) and the mazda had different tyre sizes. For now I have recalibrated it by making and applying a new speedo number face (made from a CD label sticker). It looks a little dodgy at the moment as I only made it to stick over the original face, and not to replace it. It looks better without the camera flash reflecting off it.


The factory speedo only goes to 180kph, so you get an idea of how far it would've been out.

To do it properly I would need to buy an electronic device which recalibrates the speedo, but they are expensive. The advantage would be my odometer would also be correct.

I'll probably take the lazy option and make a new speedo face up to 260kph like I have now, just neater. The odometer will be out, but the factory 180kph speed limiter will effectively be 260kph. Not that I am going to go over 180kph anyway...

Another solution here
http://www.smallcar.com/speeds.htm

seen that one a while ago, for caravelle/vanagon only

You can purchase a unit which will just plug into the standard T3 speedo, it works for both 2WD and Syncro, having two outputs. It on the expensive side and only available from overseas. But if you are not handy or just want one which works, check here
http://www.syncro-bernd-jaeger.de/TDI-Umbau/tdi-umbau.html
It's near the bottom of the page.
It's in German though.

Hi

Im not sue if this will help, I have a Stewart Warner spedo in my car, I had a ratio box made for it to correct speedo error by a company in Sydney called Speedscreen. Im thinking that you use one of these to turn the stock VSS at the correct ratio.

1302Steve

Jenny, see your email.

I have a circuit for a 1 component, 3 wire VSS that is free as long as you have 4 magnets and the wire! It is not my design. It uses an Allegro UGN3060KA IC which may be obtained as a sample (up to 2 of them) from Allegro in the US. . V E R Y simple, but it has been working in my '82 Transporter with '93 EJ22 for nearly a year.
A file is attached.
Dave
🙂

1302Steve wrote:Hi

Im not sue if this will help, I have a Stewart Warner spedo in my car, I had a ratio box made for it to correct speedo error by a company in Sydney called Speedscreen. Im thinking that you use one of these to turn the stock VSS at the correct ratio.

1302Steve

Yep. For electronic speedos, ChipTorque have an electronic calibrator that alters the PPK (pulse per kilometre) of a VSS to correct speedo readout. Proivided you already have a VSS, of course... Castlemaine Rod Shop and Pat Gardner V6 Conversions also have similar products, I think. CRS also make a co-axial cable drive adapter that you may be able to mount a VSS from a Commodore or something to a cable speedo, provided the PPK output is similar. What is teh speedo driver of your conversion - cable or electronic?

The Aussie mob YellR also make speedo recalibrators that alter the vss signal.
http://www.blackrobotics.com/index.htm

At the moment my kit car does not have a speedo cable. I plan on installing a Mazda RX-7 series 6 instrument cluster, so the circuit and installation set-up that Transparu sent me ( Thanks Dave!)sounds like the way to go at the present.

If I had the speedo cable then I might try the Commodore vss like Kombicol's new setup.

Thanks for your help.