Last year when Randy and I did a run-up test on the engine the RPM gauge was not working. So I took the computer and sensor down to Arizona to improve the design. I changed the sensor from a Hall effect sensor to a magnetic sensor. The Hall effect sensor did not sense the changes quick enough for it to work as a RPM gauge.
I used JB-weld to glue the magnets on to the arm which is mounted on the front pulley of the engine. The magnet arm is steel and the other bracket is aluminum.	I mounted the new sensor where the old one was located and ran a test by quickly passing a magnet in front of it. The RPM gauge reacted to it so all the wiring is OK. Ran engine and RPM worked perfect! 857 on start up and 882 after warmup.
Computer Calibration
When doing the run up the oil pressure read 37 while the actual gauge read 20 PSI. Also the Engine temp gauge was reading over 200 and producing a warning. I had calibrated these to 12 volts when it was on the bench but in the real world here we'll be dealing with 13.5 to 14.5 volts. So I ordered a buck converter which will hold the voltage at 12vdc no matter what the system voltage.