44
Model UT107: OPERATING MANUAL
6. Fuel System Testing
(1) GM (General Motor):
It is necessary to add more accurate engine fuel control
to a low injection automobile. Since 1980, the automotive
manufacturing industry has used electronically-controlled
carburetor and fuel injection so as to achieve lower fuel
injection.
Testing the dwell of the C-3 mixed-control solenoid: Place
the solenoid in a cylinder, monitoring the ratio between
the air and the fuel, which should generally be 14.7 to
1 between the air and the fuel so as to reduce the injection
of surplus fuel. The testing is used to see if the solenoid
is installed right in the position and the dwell of the meter
can also indirectly used for the testing.
Start the engine of the automobile to achieve a rotation
speed of 3000 RPM.
So far as a GM automobile is concerned, set the
rotary switch to the
DWELL
and select
6CYL
.
When the automobile is operating in a short fuel state
or in a long fuel state, the dwell of the meter should
be displayed between 10
0
and 50
0
.
[1]
[2]
(2) Fuel Injector Resistance Testing
(see figure 20)
(figure 20)
Black
Red
Fuel Injector
