Injector Testing

Injector Testing

Fuel Injectors can leak and bleed off fuel pressure causing hard or long starting and increased emissions. Injectors are leak tested using the Fuel Injector Leakage Tester.

- Resistance (approximately 12ohms).
- Power Supply (B+ from Main Relay).
- Status Request - Fuel Injection Signal (approximately 3.0 ms - 5.0 ms).
- EMS2000 final stage activation (see graph).


Measurement is performed on the negative B- side of injector or trigger pin of EMS2000.
Voltage is 12 volts when injector is not active.
EMS2000 pulls voltage to ground causing injector to open.
When EMS2000 releases ground, injector closes and voltage spikes due to induced voltage in coil winding of injector.

Injector Leak Testing

Special Tools For Leak Testing:

When testing the fuel injectors for leakage, use Special Tool 88 88 5 000 362. Injectors should be leak checked for complaints of long cranking times. Refer to, Checking Injector Valves For Leaks and Cleaning.