The problem is the speedo on my HPT software (or any other scanning software it seems) runs about 13x slower than my actual speed / car speedo on dash. My car speedo works perfectly.
If I'm doing 70, VCM Suite will be saying 5.
If I'm doing 7, VCM Suite will be saying 0.
So if I log a 0-100 run, my speedo will just go from 2 to 3 to 4 to 5 to 6 to 7 to 8. That's it.
I changed the speedos Math formula.. x'ed it by 13. So now it goes 26, 39, 52, 65... but that still sucks.
My car is a 30yo GM with digital instruments (dash) from factory. No ABS. Factory hydraulic auto trans.
Here's some wiring info:
LS1 PCM
RED pin 20 -- VSS Low signal -- Tan wire
RED pin 21 -- VSS High signal -- Blue/White wire
RED pin 50 -- VSS (digital) signal -- Violet/White wire
Cluster plug
C15 -- Speed sensor Low Input -- Purple (purple to VSS)
D11 -- Speed sensor High Input -- Yellow (to tan/white to VSS)
D12 -- Vehicle speed Output -- Brown/White from the dash to Brown to the ECM
D3 -- Speedo ground -- black/white
I've tried every wiring combination from what I remember. It will either read 13x slower on the scanner, or no reading at all.
The only thing I can think of is one of the cables might need a resistor.
Anyone know?