@james-meyers, I will ship the RPM sensor ASAP. 

As for the driver, do you mean the USB driver (if you use Windows 7)? If you are able to connect via your phone or something then software is a snap!

@admin I just ordered a speed sensor from you so will wait for that and see what happens.  Trying to update the firmware and software while I wait and struggling with getting it to find the driver file that I downloaded.  Unfortunately I don't have WiFi in the shop area to do this online.

Each time I go to look for the file it says no driver file is found.  But I can see the file in the folder.  Any suggestions?

@james-meyers, yes cable must be shielded. Also make sure the trigger wheel is very accurately made, because the time between each pulse is measured. If you do a run and send me the raw log file I can take a look at the signal. 

@admin Did a little machining last night and got my sensor and tone wheel mounted.  This is the exact setup I used on my previous homemade waterbrake.  

As of now I still have the erratic signal, it's a little better but not great.  The only thing is I didn't have any shielded cable to connect this with so I'm wondering if that is part of my issue right now???

Thanks

Yes, go for that!

@admin would 4 pulses per rev be suitable?  I think I can make that work as I had that same thing on my previous dyno and it seemed to give smooth results with the speed sensor I used.

Thanks again for the help, I really just want to start making some power, lol!!

@james-meyers for an engine dyno you don't need as many pulses as a roller based dyno. For example 6 pulses gives 200 samples per second at 2000RPM. 

@admin it is not a shielded cable.  But if this is not going to work I'm not going to keep working on this option.  

In my setup the problem with a trigger wheel is getting enough pulses.  The drive on the back of the dyno is very small and then to do 20 to 30 pulses I need a good size wheel, which the drive won't support.  I've already been down that path and it didn't work.  

Hi, you need a trigger wheel and a proper RPM sensor. See https://yourdyno.com/YourDynoHelp/brake-rpm-sensors/

Since you run an engine dyno and probably have turned off the "Compensate for inertia effects during acceleration"-option you can strictly get a way with not running a trigger wheel and only have 1 pulse per revolution. But chances are the signal from the coil is noisy either directly or through induced currents in the wires from the ignition. You probably need to take a look in with an oscilloscope to be sure what is going on there. Do you have a shielded cable?

I really recommend running an RPM sensor and a trigger wheel. 

To check the raw data you can do a run then open the raw log file in excel like this: Data->Get external data from->From Text->(open the .log file)->Delimited->":" in Other->Finish. Then plot column C (which is the inverse of RPM times some factor). It shall be smooth.