914turboford

I have tried 4 different Vehicle Speed Sensors and still cannot measure the proper signal coming from the PCM to the cruise control/speedometer. According to AllData I should see a "varying voltage around 5 volts" when the wheels are rotated by hand coming from wire 13 (dark green/white). I have tried a Volvo speedo head mounted VSS, a Dodge K car VSS, a Ford ABS sensor (made by ATE) and a GM sensor that I think goes into a 4L60E. All of these sensors are used and I can't guarantee that any of them work. What type of sensor should I use to insure that I get the right signal to the PCM so that it sends the 4000 pulse per mile signal to the cruise?

The car: 1975 Volvo 245 with 1997 Firebird 3.8 V6 (PCM has most of the same pins and works much like an LS1 PCM).

Brian

70 LS1

iTrader: (1)

Sounds like there are 2 issues. First is you need to get the proper type of signal to the PCM. That would be the VSS and any VSS from a 4l60 or T56 will work.

Next is you need to calibrate the PCM to adjust for your rear end ratio and tire size. These are both factors in your vehicles speed. Once the PCM is calibrated you will get the correct signal to your speedo.

914turboford

Do you think the VSS must be from a 4l60e or t56 to send the proper signal? What are the differences in signal types from VSS's? Are there more than two types?

G-Body

iTrader: (4)

The sensors that you are trying to use, are they sine wave AC output sensors? The LSX series motors use sine wave sensors. What year was that GM sensor from, might be a old style square wave sensor, I think GM used square wave sensors up to the point of LT1 motors. Download the Jags That Run vehicle speed sensor chapter, You can probably ID the output of you sensors from that and see if any will work. http://www.jagsthatrun.com/

914turboford

Thank you G-Body. That article was very helpful.

Brian