Setting VSS

Turbo3 · Posted: Fri Sep 14, 2007 9:23 am Post subject: Setting VSS

Just wondering what other people are typically getting for pulses per revolution setting for the VSS. Going to be setting mine shortly and curious what others had so I had a relative baseline to shoot for.

Also - when it refers to the 1:1 gear ratio this is referring to the gear box (typically 4th gear), correct? 4th gear (in my case) is where I should be setting the VSS then?

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

The pulses per rev varies widely from vehicle to vehicle. Some ford transmissions use as little as 6 where some GM transmissions have as many as 40. The 1:1 ratio is used when the speed sensor turns at the same speed as the wheel. Like an ABS sensor.

Russ

Turbo3 · Posted: Fri Sep 14, 2007 9:47 pm Post subject:

Hopefully I'm just missing something simple but... I tried to set the VSS tonight and it did not work. Input the tire/wheel parameters, uploaded it to the unit and took off. Followed another car with walkie talkie for speed updates, pulse input field value from 1 to 20 just to see, hit the update button, and nothing changed/happened. Tried it a few times and cannot get the VSS field to change.

What am I missing?

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

There are few things that must be known to correctly setup a speed input. First, what type of sensor are you dealing with? Hall Effect or Magnetic? If you don't know usually you can tell by how many wires it has. 2 wires is usually magnetic and 3 is usually hall effect. If the sensor is a hall effect is might need the pullup resistor enabled.

The trigger levels and filter values must also be adjusted for your vehicle. For hall effect sensor usually you can just set the trigger level to 2.5volts and it'll work just fine. The magnetic ones can vary. Start with 1.25 and see if that works. Set the filter value to 2 also. You can turn this up later if you have problems with the speed sensor picking up noise at higher vehicle speeds.

Are you using a factory sensor or aftermarket one? If its a factory one I can probably tell you exactly what the settings need to be. Let me know if any of this helps.

Russ

Turbo3 · Posted: Sat Sep 15, 2007 1:52 pm Post subject:

Russ - I've got the Huttner Enterprises built RX-7. Tim has went through the VSS once and have the pull-up circuit. I've got the car home now so Tim's not able to directly help except via phone. Tim said the sensor is a PM style as well not sure if it's factory or if he purchased it through you?

The voltage is currently set at 1.25.

Resister is set to "none".

Filter is 2, Glitch is 3.

Turbo3 · Posted: Thu Sep 20, 2007 8:17 pm Post subject:

Any updates on my VSS situation?

Russ · PCS Employee Joined: May 12, 2004 Posts: 286

I've been out of town this week. I will be in the office tomorrow. I'll give Huttner a call and figure out how its hooked up so we can setup the input correctly.

Russ