MS3 Basic VSS input trouble
 

Hello to all. After losing the function of my speedometer due to a bmw trans swap I am trying to get a speed reading through my ms3 basic. I am trying to connect an abs sensor to the VSS input with a VR conditioner. So far I have connected the front left abs sensor to the VR conditioner, gave it 5v from the db37 connector and grounded it to the chassis and connected the output to VSS1 (PE0). I've jacked up the car to rotate the wheel but so far I'm not getting a reading. I tried to switch the 2 abs wires but that didn't do anything. Should I use a different ground for the VR conditioner? I have uploaded a pic of the way I have connected everything just without the 2nd abs sensor and the setting in tuner studio. My ecu knowledge is not that good so any help would be much appreciated.

https://cimg4.ibsrv.net/gimg/www.mia...08aaecf735.jpg
https://cimg5.ibsrv.net/gimg/www.mia...836eaa7576.jpg

That's 5V input, not 5v out, right? Needs to be hooked up to vref or powered another way.

I got it connected to 5v supply for sensors 22 on the list. I'm dumb. I don't have a vref on the options loom. Would anything else here do?
https://cimg0.ibsrv.net/gimg/www.mia...0892702212.png

Yep, voltage reference supply. Different names for the same thing, usually 5V on late model stuff.

I'm not sure why it's not working. Either leg of the ABS sensor to either input of the board should work, it doesn't have the parallel resistor installed across the input legs which is never good for miata WSS on that MAX chip. The board has built in pullups, so you don't need them inside the megasquirt.

Do you have a series 1K/10K resistor installed on the output line, like most of the megasquirt manual shows? ~300 ohms was too much in my experience for reliable input into a timer of a separate non-megasquirt microcontroller, max9926 and miata WSS with a 10k pullup, but at 3.3V not 5V...

Add a 1k or 10k resistor like this?
https://cimg7.ibsrv.net/gimg/www.mia...8deedc7778.jpg

Good news! I hooked up the output from the vr board to a digital input which in my case is Tableswitch and now i got a speed reading in tunerstudio! Now I’m thinking to try and make the speedo on the dash working but I’m still goind my research on that.

Watch out - some of the digital inputs on the MS3 have lower sample rates than others.

I did similar with a VR board and the ABS sensor (connected to datalog in) and when you got to about 80mph it would drop out. From memory the Flex Fuel input is high frequency, as is VSS1.

Maybe VSS1 needs higher frequency and wheel speed and thats why i dont see the gauge moving when i spin the tire by hand? I'll take her for a spin and see.

From your settings, your wheel diameter looks to be way off unless you are running 1.9 m tall monster truck tyres.. ;)

With 205 50 15s mine's set at 0.584 and is only a few percent out..

I changed it to .585 when output was going to vss1 and the needle still didn't move. But i'll still try vss again on the road.

I can confirm that there is no speed reading on vss1. There is on Tableswitch. I did some research on how to send a signal to the speed cluster and found that aidandj used a 5v pullup to vss out and connected that to one of the 2 wires for the original speed sensor. Now he used an injector out for that so can i use another output or does it have to be specifically an injector output?

Speedo works! Got the orange speedo wire connected to a programmable output using 5v pull up and a 1k resistor following this thread: https://www.miataturbo.net/ecus-tuni...-sensor-85749/ . Just have to tidy up the wiring and test it out on the road.
https://cimg2.ibsrv.net/gimg/www.mia...c654a78b25.jpg

Yup, drops out at 80km/h here :D . Gonna try the flex fuel input .

Verify that you get a speed reading if you quickly tap the grey/blue wire to a ground (that's PE0). If you do get a reading, you know that the input is working correctly. Note, this input already has a 5V pullup, so remove it from your external circuit if it has one as well.

Will do! Thank you for the quick reply. The 5v pullup is on the output side that goes to the speed cluster. Do i still remove it?

No, leave that one as is.