Can anyone tell me what signal the ECU looks for from the VSS? I'm really wanting to get the speedo working in my willys. I'm using the stock 2000 Beetle cluster so I'll need to track down the ecu wires to the VSS then figure out how to send the proper signal. I'm in the very beginning stages of this little project and I'd like some pointers and ideas if anybody has one. All the info I'm finding is for just getting cruise to work, not the speedo.
VSS signal to ecu
- Thread starter rooney77
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jimbote
Certified Volkswagen Nut
it looks for a pulsed conditioned signal ...EDIT! 8000 ppm....lots of ways to get a signal to your cluster but the easiest may be simply adapting a stock mkiv vss to your transmissions speedo drive then stepping the signal down with a dakota adapter until your speedo agrees with your true road speed ... another way is to add an abs reluctor and sensor to one wheel and again using a dakota converter .... or even magnets ziptied to the driveshaft with a simple two wire pickup sending pulsed waves to a converter ... you could gut a stock sender and have it in proximity to spinning mags on a driveshaft or axle flange ... using the correct number of magnets could eliminate the need for a converter box ...
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AndyBees
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So, are you looking for the circuit(s) that send the info to the ECU?
I can look up the wiring on my alldata. I'm trying to figure out the signal sent from the vss to the ECU. Particularly how many pulses per mile. With that info I can make a hall effect sensor send a reasonably close signal. Assuming the oe vss was hall effect.
jimbote
Certified Volkswagen Nut
which is why i suggested using a stock vw vss adapted to your transmissions speedo drive.... as a matter of fact all my suggestions took that into consideration ... no dice?
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jimbote
Certified Volkswagen Nut
oem vss is NOT a hall effect it's a conditioned square wave (read my first post above) pulses per mile (ppm)= 8k to a ...white/blue wire, don't know what pin as my notes are at the shop
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kajikidu
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a hall effect sensors output is a square wave signal
http://www.wellsve.com/sft503/Counterpoint3_1.pdf
http://www.wellsve.com/sft503/Counterpoint3_1.pdf
Aaah, well that makes more sense then. The Jeep vss is a gear reduction unit that would spin a cable. I need to get a VW vss in my hands and see what I could do to adapt it then. What triggered the pulses? Just a magnet or notches in a shaft? Wish I still had the vw Trans to dig into.oem vss is NOT a hall effect it's a conditioned square wave (read my first post above) pulses per mile (ppm)= 8k to a ...white/blue wire, don't know what pin as my notes are at the shop
kajikidu
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here is what I will be using (probably need the Dakota converter also)
http://www.brantz.co.uk/PDFs/Universal Speedo Cable Sensor - BR1.pdf
or this one,not exactly sure yet
http://www.brantz.co.uk/PDFs/Japanese Gearbox Sensor High Grade - BR3HG.pdf
http://www.brantz.co.uk/PDFs/Universal Speedo Cable Sensor - BR1.pdf
or this one,not exactly sure yet
http://www.brantz.co.uk/PDFs/Japanese Gearbox Sensor High Grade - BR3HG.pdf
Very interesting. I wonder if I could use the later model mechanical/electrical Jeep vss and the Dakota digital to get a VW friendly signal. Guess I'm off to figure out what signal the Jeep used.
kajikidu
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the one I'm referring to is
http://www.dakotadigital.com/index....t_id=126/category_id=287/mode=prod/prd126.htm
http://www.dakotadigital.com/index....t_id=126/category_id=287/mode=prod/prd126.htm
Aaah. That may fit the bill. Thanks for the link.
jimbote
Certified Volkswagen Nut
OK i stand corrected on the hall sensor... I was confusing it with an inductive pickup which outputs sine wave ....rooney, if you need a vw vss I have plenty laying around from auto to manual swaps ...yours free for the asking
jimbote
Certified Volkswagen Nut
yes!...the sgi-5 is what I'm using in my truck.... instead of a true VSS I use the tach signal fed from the ecm conditioned by the dakota then fed back to the ecm on the speed input wire... works awesome ....
I'd be more than happy to take a manual vss off your hands. I'll shoot you a pm. Thanks a ton.
jimbote
Certified Volkswagen Nut
it'll be an auto vss but functionally the same as the manual
Sounds good. Thank you again.
vwjoel
New member
So how many pulses per mile are you running? I have a 5 magnet disc on my CV joint with a hall sensor for my ALH in an 86 double cab. I got a VSS code in VCDS so I went to 1 magnet and I still have the code. I'm trying to get the cruise to work but I am not running a Mk IV cluster like Rooney. Do I even need a valid VSS for cruise?
I now have a working speedometer! I used the stock YJ VSS in my dana 300 transfer case. It's not accurate but that will take some fine tuning. It's accurate in 4th gear at idle but at 2500 rpm the vehicle seems to think I'm doing 90mph. I think with the vcds adjustment and a regear at the vss I'll be much better off. Thanks for all the information and help.
8000 ppm is what the ECU wants and what the Jeep VSS sends. As for your situation, you'll need to figure out how many revolutions per mile your driveshaft makes then use that to determine how many magnets you need. Basically each magnet equals a pulse. So if your driveshaft spins 2000 times per mile you need four magnets to make the 8000 pulses per mile the ECU wants. And yes, you need a VSS for cruise, or a way to fake it.
jimbote
Certified Volkswagen Nut
you can use your tach signal like i did in my truck swap
Since you actually use one, would the SGI-5 allow me to "fine tune" my VSS signal to get the correct speed?
jimbote
Certified Volkswagen Nut
yessir.... it had a wide output adjustment range
May pick one up then. Seems it'd be a whole lot easier to mess with than changing the transfer case gear.
Bczuk
Veteran Member
I went with one too. Worth the $80 imo
So as I said I tested the vss last night. I’m using a VSS for a 99-ish Jeep wrangler (should be 8000ppm). I had the rear driveshaft off and the front output disengaged. I put the jeep in 4th gear and revved it up to 2500 rpm. According to my calculations that should put me at 63-65 mph. The speedometer read 90 mph. The odd part is that when it was in 4th gear and idling the speedometer read approximately 25mph, which is about where it should be (903 rpms). So what would cause the drastic differential when rpms increase? I’m starting to think I have a separate issue beyond a simple incorrect driven gear in the VSS.
jimbote
Certified Volkswagen Nut
8000 ppm may be incorrect for the VW mkiv... I'm going by a cruise control guide that lists the 96' vw's as 8000ppm... maybe they are lower now?
From what I've been able to find, they are 8k ppm until the mkv. The mkv used a reluctor ring on the hub. It did both abs and vss. That's assuming I understood it all correctly. Wouldn't be the first time I completely misunderstood though.