TheSamba.com :: View topic - $3 VSS – speed sensor

Sat Dec 06, 2014 7:22 pm

$3 VSS – speed sensor - cruise – Subaru

bolt head passes under sensor and generates a speed signal

LJ12A3-4-Z/BX Inductive Proximity Sensor Switch NPN DC6-36V

Ebay search – http://www.ebay.com/sch/i.html?_from=R40%7CR40&...PrefLoc=98

12/6/14 $2.47 Asia, $3.25 form US

Based on the Rocky Mountain West VSS - http://www.rockymountainwesty.com/product_p/rmw-ch395ss.htm

I bought the RMW VSS but my AutoZone lifetime CV axles have a different boot flange profiles so the RMW metal ring became out-of-round when I tightened the bolts. This caused the distance between the sensor and the ring to vary in distance. Interestingly <30mph, that ovaling wasn’t an issue, however over that speed the reading became erratic and even at 70mph it showed about 47mph.

Middle of the night AHA!!! - use the bolts.

The RMW and SC have 5 sensors and there are 6 bolts so at actual 72mph I get shown on the Torque app 80mph. Not an issue since 1) Torque has a custom speed calibration 2) the cruise control cares about relative and not actual speed and 3) the Subaru ECU just needs varying speed. The Subau ECU doesn’t like speeds above 120mph but that means I would have to be doing 108 mph before it became an issue. BTW, the Torque factor for me was 0.9 = 15” rims with BFG tires.

Also the cool thing about this sensor is that it has an indicator light that illuminates when the sensor triggers so you can see if you have it set right when you hand-turn the wheel. Be aware that in my ovaling issue mentioned above it illuminated at slow speed but had issues at higher speed. Also – I read that closer is better for this sensor. I have mine about 2mm off the bolts. Don’t stress about putting it too close since the plastic end can withstand some abuse as I learned when my ovaled RMW ring hit it.

Sat Dec 06, 2014 10:04 pm

Right on, that's cool. Always feels good to figure something out 8)

Thanks for posting up the details.

-Kevin

Sun Dec 07, 2014 8:57 am

I like that!!

Sun Dec 07, 2014 9:11 am

nice find. can you describe the wiring [since hong kong parts usually come with minimal instructions]?

my guess is that one the leads is powered and the other 2 are the usual sensor pick-up.

fwiw - looking at it for a different application than what you did but helpful nonetheless.

Sun Dec 07, 2014 9:23 am

I'll have to check how mine ended up but if I recall correctly:

+ = Brown
- = Blue
sensor = black

from - http://www.cncmaker.com/filesupload/proximity_connectionLJ12A3.pdf

Connect the wires in the following order by finger twisting the bare ends together
and covering the bare connection with the small wire nut. The black common should
be connected to the power feed common of the control power system. The brown
wire will tied to the power feed voltage, 12VDC to 36 VDC, depending on the type of
switch. The blue wire will be connected to the device that is being electrically
controlled, usually a small electric relay.

Sun Dec 07, 2014 9:34 am

Good stuff!

Sun Dec 07, 2014 11:02 am

So are you running a Subaru cruise set up or a Vanagon ?

Stacy

Sun Dec 07, 2014 11:08 am

16CV's wrote: So are you running a Subaru cruise set up or a Vanagon ?

Stacy

Rostra universal http://www.rostra.com/universal-aftermarket-cruise-control-by-rostra.php

it is nice since it is electronic and not vacuum.

Control button also fits nice in the lower right blank space on the VW instrument cluster http://www.rostra.com/aftermarket-cruise-control-switches-by-rostra.php

it sits really well in the corner by the electrical junction box and the cable length is ideal to reach the throttle cam.

Sun Dec 07, 2014 11:57 am

Awesome!!! Just bought 10.

The vendors have quite the mark up on these.

I also use Rostra aftermarket cruise control. They have a stalk that looks factory also.

Sun Dec 07, 2014 12:19 pm

which signal divider are you Guys using for a Syncro?

Sun Dec 07, 2014 12:36 pm

jrobewesty wrote: Awesome!!! Just bought 10.

The vendors have quite the mark up on these.

I also use Rostra aftermarket cruise control. They have a stalk that looks factory also.

From where! how much?

Thanks!

Sun Dec 07, 2014 12:40 pm

I am thinking of mounting this on my front inner CV and using a 2WD Cruise module (ECU) and By passing my shared signal from my GW VSS which feeds my Subaru ECU.
The upside of this is I can use the now unused OXY sensor wiring to tie into the factory VSS from the cruise ECU.
I have a factory cruise installed which barely functions. this might be the answer.

Stacy

Sun Dec 07, 2014 1:54 pm

Vanis13, I need to replace the old Audiovox CC system and this looks ideal. The links you gave were for a bunch of products. Can you give me links to the retailer you bought from and the specific system (I have a Subie EJ25)? Thanks! :D

Sun Dec 07, 2014 2:08 pm

curious, what are you using for the VSS now?

Sun Dec 07, 2014 2:17 pm

An older Audiovox system that has crapped out and is mostly NLA (although there is another clone of it).

http://www.amazon.com/dp/B00029WQTW/?tag=googhydr-...5tlril8k_b

Sun Dec 07, 2014 2:44 pm

dobryan wrote: An older Audiovox system that has crapped out and is mostly NLA (although there is another clone of it).

http://www.amazon.com/dp/B00029WQTW/?tag=googhydr-...5tlril8k_b

created a topic on the Rostra CC to keep Qs specific to that unit there.

http://www.thesamba.com/vw/forum/viewtopic.php?p=7472309#7472309

the VSS stands for Vehicle Speed Sensor.

Look at that post and ask away. The Rostra is a great unit.

Sun Dec 07, 2014 3:34 pm

As for engine conversions and aftermaket cruise controls go, the ecm or cruise box needs to see some kind of speed.

I'm not worried about it being dead on. Depending on gearing and tire size no one I know makes an adjustable one to dial it in.

On OBD2 conversions, I use torquepro for gauges, they have an option for a GPS speedo instead on what the ecm is reading from the sensor.

Sun Dec 07, 2014 3:37 pm

My only question is that the vendors option uses magnets spinning on that axle.

Did you put little magnets on the CV bolts or is this senor different and have the magnet in it like can and crank sensors?

Sun Dec 07, 2014 3:40 pm

This sensor detects metal moving by (or to/from) it.

The small car speed ring one uses magnets.

The RMW uses this type of metal sensing sensor and picks up on the METAL tabs that protrude from their cool speed ring.

In this case, the bolts provide the metal moving by the sensor to trigger the sensor.

Sun Dec 07, 2014 4:09 pm

Check Andrew Flint's reversed 1.8T builds.

He drills the rim of the CV boot flange with the number of holes needed to activate the sensor for traction control.

Not exactly cruise control, but same trigger.