Application: All engines with P-7100 and P-8000 Series R Bosch pumps. It's simple to set up and easy to use. Install the fixed timing probe into the opening on the injection pump and connect the ground clamp. Turn the Position Sensor on and you are ready to bar the engine to check timing. For any pump to engine timing procedure the "A" lamp will light first, when both "A" and "B" lamps are lit you are at the desired timing. Next rotate the flywheel or pump hub counter clockwise at least 45-degrees and repeat procedure to verify timing. When "A" and "B" lamps are lit you should be at desired engine to pump timing.