Hey there, new to the forums. Basically what I have is a 97 blazer overhead console. I'm putting in a 82' camaro but I can't seem to find the VSS information anywhere! My personal car forum is no help, so I'm coming to you all asking what type of VSS was in this truck! It's a 97 4x4 4l60e automatic truck. I just need to know the PPM or type so I can buy an adapter for my th350, pcm swap is not practical since my car is all mechanically driven.

 

Is this what you were looking for.

DESCRIPTION
The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the VCM how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft.

OPERATION
As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse.

The VSS produces an AC voltage signal that increases with vehicle speed. The VCM processes this signal and sends it to the following components:

Instrument Panel.
Cruise Control Module.

Mark K

 

Almost what I was looking for! There is 4000 ppm and 8000ppm and I believe one more option that can be found on these trucks, trying to see what trucks came with what.

 

If I remember correctly, the tone ring in the back of the transmission/transfer case is a 40 tooth ring. This results in 40 pulses per revolution of the driveshaft. To get to pulses per mile, you need to do the conversion from ppr to ppm which requires the axle ratio as well as tire diameter.

To convert from the 40 ppr at the VSS to a ppm value, you take 5280 ft/mi divided by the circumference of the tire (in feet) to get rev/mile, then you have to multiply by your axle ratio to correct back to the VSS location that gets you the driveshaft revs/mile which is then multiplied by the 40 ppr.

 

Great Subject. Cars are amazing when you
look at what they are really doing in detail.

For Tire Circumference.
Tire Diameter And Circumference Calculator

Please see the Pdf attachment for an extra good explanation on the VSS.
If you like math, this one simple part is doing a lot of work.


Mark

 

Thank you both so much! I do not believe I even have to calculate it... If I'm not mistaken I believe I can get a 40 tooth adapter on the th350, if not I know for sure I can bolt a 4l60e tailshaft on the th350. But I'll do some research with the info you all gave me. Thanks again!

 

This is some good stuff !!! But I think I am going to have reread it a few times before it sinks in though. LOL

 

Compliments to Swartlkk,

He kick started the interest with his math equation.

In general terms, yes I knew what a VSS was/does.
I have had one replaced at mile 208,000.
Never really thought too much about it. I just wanted my
truck to be running again. Kind of like changing your battery.
Now I really know where/what the VSS's real function is in detail.

Thanks - Mark K