Fuel Injector: Testing and Inspection
INJECTORRequired Special Tools:
- MB991348: Test Harness
- MD998464: Test Harness .
Measurement Method
1. Disconnect the injector intermediate connector, and connect the test harness special tool (MD998464) in between.
2. Connect the oscilloscope probe to each injector intermediate connector terminal to analyze each cylinder:
- Terminal 2 (black clip of special tool) for the number 1 cylinder
- Terminal 3 (blue clip) for the number 3 cylinder
- Terminal 4 (white clip) for the number 5 cylinder
1. Disconnect the injector connector, and connect the test harness special tool (MB991348) in between. (All terminals should be connected.)
2. Connect the oscilloscope probe to injector connector terminal 2.
Alternate method (Test harness not available)
1. Connect the oscilloscope probe to ECM
2. Connect the oscilloscope probe to ECM
3. Connect the oscilloscope probe to ECM
4. Connect the oscilloscope probe to ECM
5. Connect the oscilloscope probe to ECM
6. Connect the oscilloscope probe to ECM
Wave Pattern Observation Points
Point A: Height of injector coil induced voltage.
Point B: Injector drive time 1. The injector drive time should be synchronized with the scan tool tester display. 2. When the engine is suddenly revved, the drive time will be greatly extended at first, but the drive time will soon return to original length.
INJECTOR CHECK
1. Disconnect the injector intermediate connector.
2. Measure the resistance between the injector intermediate connector terminals.
Standard value:
3. Connect the injector intermediate connector.
1. Disconnect the injector connector.
2. Measure the resistance between injector side connector terminals 1 and 2.
Standard value: 13 - 16 ohms [at 20° C (68° F)]
3. Connect the injector connector.