Case 680B, 680C Loader Repair Manual

Manuals: Service Manual
General
Engines
Fuel System
Hydraulics
Steering
Power Train
Brakes
Electrical System
Mounted Equipment
Manual Extract: Checking Injector Operation on Engine
If the engine is misfiring on one cylinder, it is reasonable to suspect that an injector is not functioning correctly.
NOTE A faulty injector will show up more readily at idling speed.

A faulty injector can be located by loosening the high pressure fuel line fitting on each injector in turn while the engine is running. This will allow the fuel to escape before it reaches the injector and thereby cut out that particular injector. Use 3/4 inch open end wrench.

The cylinder least affecting engine performance is usually the one with the faulty injector. The recommended method of accurately determining how much engine performance is affected is as follows:

1. With the engine warmed up to at least operating temperature, check the engine idling speed (throttle in idle position) and the no load full governed speed (throttle fully open). Use an accurate tachometer as directed on Page 1-32.

2. Cut out each injector in turn and check both the engine idling speed and the no load full governed speed. The injector that least affects the engine speed is probably the faulty one.
NOTE Whenever an injector is suspected to be faulty, the Powrcel opposite it must be removed and checked as well as the injector.
A plugged or damaged Powrcel will affect engine performance in much the same manner as a faulty injector. A faulty injector will also foul the Powrcel opposite it.