The Tester produces a simulated trigger signal that fires the ignition just as if the engine was running. A special, load-pro­ducing clip-on spark plug is included to connect to the coil wire. If the spark is unable to jump the gap of the tester, there is an ignition problem and you can track it down. The Tester has an LCD display that clearly shows the simulated rpm. This also allows you to test the accuracy of any rpm limits, rpm-activated switches, shift light operation and your tachometer. The Tester operates on 4, 6 or 8-cylinder engines and will simulate up to 16,000 rpm. For racers with our Digital Programmable 7 Ignition Controls that are using a non-magnetic pick-up as sync signal for Individual Cylinder Management, the Tester has a circuit to check its operation too. This Tester will check the operation of all of MSD's single-channel CD Ignition Controls. Once the ignition tests good, you can continue troubleshooting and find the culprit.