I have an 88 GTA which has the electronic VSS. It's my understanding that my 165 ECM gets a 2000ppm signal, whereas the 730 ECM im swapping to will need 4000ppm. What does the 88 electronic VSS output? I know it goes through a buffer box and was wondering if it gets buffered from 4000ppm to 2000ppm or if it just outputs 2000ppm, and in that case would need to be swapped for a 91-92 VSS.

Thanks,
Matt

 

Good question, the actual VSS in the transmission is a 4-pole unit. That is 4000 PPM.

Currently, the VSS feeds a 4-OUT Buffer box, which then distributes the signals. One to the speedometer, another to the cruise control, and another to the ECM (2000 ppm).

If converting to mask $8D (TPI code), you have two choices:

1) Keep the current VSS/buffer setup and flip a bit in the PROM/BIN (mag/optical).

2) Remove the 4-out buffer and wire the VSS signals directly into the ECM. The '7730 ECM has the same circuits as the 4-out buffer. And is the way it is run in TPI f-body's.

RBob.

 

So, if I ditch the 4-OUT buffer box and feed it directly to the 730, will I still need to flip the mag/opt switch (or is the switch essentially 2000/4000)? The 730 has the appropriate 4000ppm output to drive the speedometer then, correct? (I no longer have cruise control)