VSS Required?

[sexychevy10]

i have looked at a few harnesses in the after market for a 5.3 for a swap and i found a company that makes one with a ecm that does not require a VSS signal but uses engine RPM. Is this possable? i have read on here that a VSS was critical for propper tuning. any input is apprecated!

[Chris@HPTuners]

if it's an electronic auto you need VSS for the shifting. If its a manual it will work but a lot of the PCM's features use VSS as an input. Detecting when the vehicle is stopped or moving is used a lot for idle control. You can tune around this but it's not as good as having a VSS.

[sexychevy10]

yea I planned on using a non electronic trans I'm new to tuning so this swap was probably a big undertaking. lol but this forum is very helpful!

[EagleMark]

I've done a few differant PCM without VSS. The tuning end is at least ten times the work, mainly idle and blending idle and off idle tables.

Everyone I have added VSS to afterwards was an improvement.

I will never do one without VSS again! Just not as good and to much time to make run, idle and drive right.

HTH!

[Trevtec]

Someone told me you can not run HPtuners without VSS, that it would make you run in the wrong parts of the maps. Running a TH350 and dont have a Speed sensor, is this gonna be a problem for a racecar?