VSS signal incorrect

[Ep Woody]

I've took a Arduino Nano v3 and added the signals from my ECU (fuel usage) and conditioned VSS signal. Everything seems to work, when I drive a bit it gives me a speed, and a fuelconsumption. The last part seems accurate, but the speed isn't.

While cruising at a constant speed the speed the speed jumps up and down. But what's even more strange, is the first 2-3 stops the speed drops to zero, but after a couple of miles driving the next stop the MPGuino still thinks I'm driving.

Does anyone have a clue what might be wrong?

[AndrzejM]

You may try shielded wire for VSS signal. It seems that your wire is catching some external noise.

[type-S EF awd]

I have a 94 civic DX coupe, should be the same as the 95 4dr in the MPGuino wiki which says 8214. I had to set it to 10400 to get close, and another thing is regardless of what I put in the "timeout" it won't seem to turn off itself. 7 minuites? I've waited HOURS

My suspect, is the 1.0.3 arduino software to load the uno.

In the sketch it says /* YOU NEED TO USE ARDUINO VERSION 0011 !!!!!! */
//it won't fit with the new math libraries that come with 0012, sorry.

version 0011 will not run on my machine, can anyone address both our problems?

[Ep Woody]

I've found out what the problem was. I used my laptop to power the Arduino (through USB) and I didn't have an extra groundwire from the arduino to the car. That caused false positive pulses. Once I'd changed to power from the car the problem disappeared.

[stargazerf3a]

I had the same problem with vss signal and all i did to solve this was to connect the negative pole of the mpguino to the chassis and not to the battery pole...