INJECTOR RESPONSE TIMES ON DDDL 6.5xx

The EUI (Electronic Unit Injector) uses a Solenoid operated valve to control injection timing and metering of the fuel and controlled by the ECU. Fuel injection begins when the Solenoid valve is closed.

The valve closing point known as the Injector Response Times, is also returned to the ECU. This information is used to monitor and adjust injection timing. The amount of fuel injected depends on the Pulse Width stored in the calibration which determines how long the Solenoid valve remains closed. The larger the Pulse Width, the longer the valve is close and the more fuel is injected.

To view the Injector Response Times:

1. Connecting to DDDL 6.5xx Software

2. Choose Injector Response Times from the Diagnostics menu.

3. The Injector Response Times dialog box is displayed.

To print the data in the Injector Response Times dialog box:

→ Press Print. The Print dialog box will be displayed so that you can choose how to print the data. This dialog box is also displayed when you choose Print from the File menu.

Injector Response Short

Flash Code 71 - indicates that the time it takes from when the DDEC ECM requests an Injector be turned on when the Injector Solenoid valve actually closes is shorter than the lower limit of the expected range.

This diagnostic condition is typically:

→Aerated fuel system

→High system battery (+) supply voltage

→Mechanical injector failure

→Failed solenoid

Injector Response Long

Flash Code 61 - indicates that the time it takes from when the DDEC ECM requests an Injector be turned on to when the Injector Solenoid valve actually closes is longer than the high limit of the expected range. Engine oil temperature must be greater than 87 deg F (30 deg C).

This diagnostic condition is typically:

→Bad Injector harness and or connection (high resistance)

→Poor vehicle grounds

→Sticky Solenoid valve

Injector Response Times generally increase with low Battery supply voltage and decrease with high Battery supply voltage. Although Injector Response Times vary from Injector to Injector at a given r/min, each individual Injector Response Time should remain relatively consistent from one firing to the next. Wide variations in response time (typically ± 0.2 ms) for one Injector at a steady Engine r/min may indicate an electrical problem (faulty Alternator or Regulator, poor or broken ground cables, etc).