Oscilloscope Patterns and Waveforms

INJECTOR




Measurement method
1. Disconnect the injector connector and connect the special tool (test harness: MB991348) in between. (Both the terminal on the engine control module side and the terminal on the power supply side should be connected.)
2. Connect the analyzer special patterns pickup to the test harness clip on the engine control module side.

Alternate method (Test harness not available)
1. Connect the analyzer special patterns pickup to ECM terminal 1 to analyze the No.1 cylinder, connection terminal 2 to analyze the No.3 cylinder connection terminal 14 to analyze the No.2 cylinder and connection terminal 15 to analyze the No.4 respectively.


Standard Wave Pattern




Observation conditions




Standard wave pattern

Wave pattern observation points




Point A: Height of injector coil induced voltage.




Point B: Injector drive time.
- The injector drive time will be synchronized with the scan tool tester display.
- When the engine is suddenly raced, the drive time will be greatly extended at first, but the drive time will soon match the engine speed.