Gxt V055-01 Diagnostic Analyzer Manuel d'utilisateur télécharger pdf (Page 19)

Fuel Injector Drive Test

No readings will be displayed if there are no amps pulses,

or if the pickup is reversed, or around both wires of an

injector.

Peak Amps (PkAmp) shows the peak current driving

the injector. It is regulated by the driver. Typical peak

readings for one injector are 4 amps for current regulated

drivers, and 0.7 amps for resistance limited drivers. Compare one driver bank to another.

Build Time, or ramp time in milliSeconds (mS) is affected by the solenoid and the pintle movement. Slightly

shorter-than-normal Build Time can be caused by a solenoid winding short or an injector that is stuck.

Slightly longer could be from a bad driver or wire connection. Typically, build time is 1.3 mS.

Pulse Width is shown on the lower display line. It lets you see if the injector is actively driven. Use

momentary wide open throttle to see the Min and Max range. The center reading shows what is presently

happening. The NEXT key clears the Min and Max so they can begin accumulating again.

FUEL INJECTION CIRCUIT TYPES

Sequential - Each injector has a separate driver and can be driven independently of the other injectors.

The build time currents can overlap on these systems; for valid readings check each injector separately.

Pairs - There is one driver for each pair of injectors. The current readings, as measured through the

common supply wire, will be twice the reading expected for a single injector.

Banks - Half of cylinders are driven alternately. The current readings as measured through the common

supply wire will be 2, 3, or 4 times the reading expected for a single injector.

Fuel Injection Troubleshooting Chart

Fuel Injector Hookup

Amps Build Sequential

None None Open circuit, check continuity

Low Long Wiring, connections, or driver

High Short Shorted Winding

Amps Build Banked or Paired

None None Open circuit or bad driver

High ------- Shorted winding

Normal Short Shorted winding, Driver OK

High Long Driver not Limiting

Low Long Open, high resistance, or

bad driver

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Gxt V055-01 Diagnostic Analyzer Manuel d'utilisateur Page 19