[Glavey]

Hi all!

I'm having an issue getting an RPM signal with a single-cylinder, basic distributor setup using an NO2C. With just the arduino board connected via USB to my computer, a second UNO with ardustim outputting a 1000 RPM dizzy signal to the primary engine speed input on the MEGA with speeduino.

I only had the sync light turn green in tuner studio when the rpm signal was connected, no rpm reading. I switched to a 36-1 missing tooth wheel on the speeduino board and input a simulated 36-1 signal from the UNO and I had a steady rpm reading.

I attached the tune I used when the no-rpm signal was occurring. The tune is still very preliminary; the tables are still from the speeduino template tune.

[LPG2CV]

Hi, and welcome

Only thinking out loud here

Try changing the spark output mode to sequential.

[Glavey]

Thanks for reply and the suggestion, but still no RPM.

[Glavey]

After a bit of tinkering with changing one thing at a time in tuner studio, I discovered if I change the number of cylinders to 2, the RPM gauge and everything else springs into simulated life. I'll just let the speeduino think it is controlling a 2 cyl with a shared single injector.

[LPG2CV]

What does the engine have in terms of sensor and trigger wheel, as its not going to have a distributor!

[Glavey]

Single tooth trigger wheel on the flywheel with a VR sensor shared with a CDI; the kind of setup found on carburated pit bikes, scooters, and the like.

I probably should have mentioned that this will be a fuel only install until I figure out a way to add a missing tooth trigger wheel to the flywheel.

[LPG2CV]

I dont think you could try it with arduttim, but perhaps 2-1 wheel!

[Glavey]

A 2-1 wheel produced the same sync-but-no-RPM symptoms that the 1 cyl. dizzy setting displayed. Having the speeduino think I have 2 cylinders is advantageous to this particular setup - I'm going to be inputting a crank-speed signal from the engine as a dizzy-speed signal into the speeduino. If I had 1 cylinder selected, the speeduino would read 1/2 engine speed, and I would have to do some trickery in the code to make it read the correct RPM, and it is doubtful I would do anything but break the code.

[klempnertommy]

I had the same problem on a 250cc dirtbike engine
I changed the code "basic distributor" in decoders.ino.
the only thing you have to consider is to halve the injection time because with this change it injekt each round, same like wasted spark.
you can give it a try
https://gist.github.com/Klempnertommy/4 ... 8953bb0237

[Rydec]

I think 2 cylinder should give correct rpm for single cyclinder 4 stroke CDI system. I have the same problem, used to work on firmware prior to MAY but will give wrong RPM reading. Dizzy only give 1 pulse per 2 rev while CDI have 1 pulse per rev.
http://speeduino.com/forum/viewtopic.ph ... be9c4486fb