Nistune Forums

Good Morning/Evening

I'm working through a transplant project and having a bit of a struggle with VSS inputs to the S14A Kouki ECU and a Classic Instruments speedo simultaneously. Currently I'm running my VSS wires to a Classic Instrument (Dakota Digital) box to convert the pulses to a square wave. Then the output of the box is routed to both the speedo and the ECU pin 2. When I calibrate the box to increase the PPM (pulses per mile), I can get the speedo right but the ECU maxes out on MPH and hits fuel cut logic. So, any body know the functional logic of Speed Limit 1, Speed Limit 2, and Speed Limit 3 in the S14A ECU? Does changing the tire size in Nistune recaibrate the pulses or simply a Nistune display calibrate?

Regards,
Steve

The display changes in Nistune for tyre size are only display and do not affect ECU operation

In fact that part cannot be changed. The signal gets converted by auxillary chips from pulsewidth into a number 0-255 which then x2 to get actual speed. It is compared against various parameters in the ECU including the soft and hard speed limiter checks. You can increase these perhaps or find a way to fix up the signal going in