I did a TPI conversion on my truck, and it runs fine. I bought a VSS from JTR, and it will not read the vehicle speed in Tunerpro. I tested the VSS on a freq counter, and it shows varying AC voltages and frequencies when spun by a drill. I checked continuity from the VSS connector to C2 and C8 on the ECM plug, and it was good. I am using SAUJP 305 bin I downloaded from the Moates files. Is it possible speed sensor bits are set wrong? I do not know which ones should be set for normal operation. Current configuration:
Bit 0: not set
Bit 1: not set
Bit 2: not set
Bit 3: set
Bit 4: set
Bit 5: not set
Bit 6: not set
Bit 7: set
Thanks for any advice!
Gary

 

A '7727? If you are referring to option word 3, bit 6 needs to be set for a mag VSS.

RBob.

 

Oh yes, 1227727 ecm. I tried to include all the pertinent info and forgot that! I see bit 6 in the flag/switch area, but not option word 3. What is that?

 

This one:

Switch 18 (L8018) - Bit 6 - Type of VSS Installed

RBob.

 

I set bit 6 and tried it again. Got immediate MPH reading on the laptop. I wonder what the other VSS bits do?
Thanks!

 

Ip Divisor !

B7 b6 b5 b4 b3 b2 b1 b0 (b4-b0 are not used in the correction)

B7 set = (10000000) value of 128... speedo reads 96 mph
B6 set = (01000000) value of 64... speedo reads 83 mph
B7,B6 set = (11000000) value of 192... speedo reads 73 mph
B5 set = (00100000) value of 32... speedo reads 65 mph
B7 , B5 set = (10100000) value of 160... speedo reads 58 mph
B6 , B5 set = (01100000) value of 96... speedo reads 53 mph

 

Hi, Brian

So the other bits are just for speedo correction? I am using a mechanical cable drive speedo, so these would not matter how they were set for me? But, bit 6 must be set to use magnetic vss.
Thanks!

 

Your right just leave 0x18 (switch 18) bit 6 alone and it will be set to magnetic. In hex D for magnetic or 9 for optical.