GxT Ferret 54 ENGINE DIAGNOSTIC CENTER - Manual (Page 46)

POWER BALANCE - Automatic and Manual - Distributor
Press POWER, SELECT Power Balance Automatic or Power Balance Manual, and press NEXT.
Power Balance is not available when Engine Setup "Ignition" is set to DIS or Diesel .
Start 1150 RPM Killing End 1030 RPM
%Drop 10 11 10 9 10 3 10
Cyl # 1 3 7 2 6 5 4 [8]
On distributor engines, power balance, or each cylinder’s power contribution relative to the
others, can be seen by turning off the spark plugs one at a time and measuring the drop in
RPM. In Automatic mode, the Diagnostic Center will suppress ignition to each cylinder in turn,
and will display and save the starting and ending RPM for each. The more RPM decrease
seen, the more a cylinder must have been contributing. If all cylinders are contributing equally,
RPM drops will be consistent among cylinders. If a cylinder shows only 1/3 of the drop of the
average cylinder, it should be checked further with the other Diagnostic Center tests. If all
drops are very low, see the facing page for advice on defeating idle compensators which may
be raising idle speed in response to the suppression.
If the engine has more cylinders than are shown on the screen, press SELECT to see more.
4-17
The test relies upon steady timing, fixed air-fuel feed and a constant amount of engine drag
during the test to make valid comparisons between all of the cylinders. If the RPM drifts during
the test, a message will appear, indicating the test should be run again.
A steady drag on the engine can improve the test results. Turning the heater fan on high and
headlights on bright is usually the best method. Particular attention should be directed to
eliminating loads that can turn on or off in the middle of the test such as the air conditioner
compressor and radiator fan motor.
SUPRESSION CYCLES
CYLINDER
SEQUENCE
RPM
END
RPM
CYCLE 3
RPM START
1 2 3 4
* * *
RPM DROPS FROM SPARK SUPPRESSION
" * " shows recovery times