I've got a 92 formula, was a LB9/T5 car, dropped in a 350 and did a t56 swap. Did a little chip tuning to make the speedo read correct, but When I'm datalogging it always shows the vehicle speed as 0. Everything else looks and acts normal. Anybody ever seen this kind of stuff? I don't know why I can change the VSS pulse divisor on the chip to correct the speedo on the dash, but it won't show speed on the computer?

 

There are two spots that need to be changed in the chip to make it work. I dont remember exactly what they are, but a search of the DIY PROM board and/or the tranny forum should find it for you.

 

I believe those would be (as displayed in tunerpro rt) the Vehicle Speed Sensor (sets how many pulses per mile as calculated in the ecm) and switch 18, bit 6 (should toggle between optical and magnetic vss). I've played around with both of them a little bit, but didn't have any good results. I should have put that in my initial post (sorry 'bout that!) Since I did what I could find in the tune, I was wondering if it could be a problem in the wiring, or maybe something in the ECM itself or in the VSS buffer.