GxT Ferret 54 ENGINE DIAGNOSTIC CENTER - Manual (Page 42)

POWER
ELECTRONIC COMPRESSION — DIS or Distributor
Press POWER, SELECT Electronic Compression, and press NEXT. A screen may prompt
you to zero the amp probe. Follow the on-screen instructions. Electronic Compression is not
available when Engine Setup "Ignition" is set to Diesel .
Test Preparation
If a DIS ignition was selected during
Engine Setup, the Diagnostic Center will prompt you to
disable the fuel supply to prevent the engine from starting during cranking. Use the
recommended method to disable the engine for compression cranking tests, from the vehicle
service manual. This is usually done by unplugging the power wire or fuse to the fuel injectors
or fuel relay. Run the engine until it quits, to verify that fuel is cutoff. Many late model vehicles
will disable the fuel if wide-open throttle is applied before cranking. To determine whether your
vehicle does this, turn the key off, depress the accelerator pedal to the floor, and then turn
the key to the cranking position. The engine may start unexpectedly, so be prepared to
release the key and the pedal.
On a distributor engine, the Diagnostic Center will suppress the ignition during cranking. If,
for some reason, the Diagnostic Center has difficulty suppressing a particular ignition, you will
be prompted to disable the fuel supply.
Ignition power must be kept on so the Diagnostic Center will sense each cylinder’s ignition
pulse. Keep the vehicle’s doors closed during the test to keep the dome light and automatically
triggered accessories off.
The first screen shows RPM, Amps, and Battery Voltage while the engine is cranked:
ELECTRONIC COMPRESSION
Crank Engine
243 RPM Battery 10.87 Volt
132 Amps
Crank the engine. If the engine fires during cranking, the data will be invalid. Holding the engine
intake manifold throttle held wide open will help prevent some engines from firing. Data saving
will begin when cranking is sensed. Once the test has started, the display will constantly show:
ELECTRONIC COMPRESSION
Continue Cranking
Performing Electronic Compression Test
On a distributor engine, when the ignition has been suppressed, the engine will start when
the Diagnostic Center releases the ignition suppression at the end of the cranking period,
otherwise the STOP CRANKING message will appear.
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