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Page 13
IX
- Injector Mode
Injector Mode serves two purposes.
First the ability to test the fuel injector driver and second to test
the injector circuit itself.
First
, unlike standard Noid lights that require you to discon-
nect the injector harness, The HOOK can be back probed into
the fuel injectors control circuits at any location. Once con-
nected, select the Injector Mode. Now if you have a no start,
crank the vehicle and you will see the LEDs flash and hear the
speaker at the same rate the driver is controlling the injector.
Many vehicles today need to have the injector connected for
the driver to function and are impossible to access. A standard
Noid light will not work as a tester because of these limitations.
The flashing LED’s and audio monitoring of the injector driver
are designed for cranking and lower rpm’s.
Second
, the display will indicate the inductive kick voltage of
the injector circuit. This is a direct result of the strength of the
injector coil. When comparing all of the injector inductive kick
voltages, the weak coil or circuit with high resistance will stand
out. Think of this as the quickest injector circuit tester on the
planet, scope like data without the scope.
When the inductive kick voltage exceeds 35V, both red and
green LED’s will flash simultaneously at the rate the injector is
firing based on cranking or idle speed letting you know it is op-
erating. This is not to be confused with a Noid light. If you see
voltage dropping below an expected level or an unexpected
disruption in the audible and visual indicators, you will have the
information as to the condition of that injector or circuit.
Let’s understand how to use this data. No flashing LED’s and
no speaker tone can mean the driver is not working or an open
circuit. LED’s flashing/speaker tone means that at least 35
volts has been measured in the inductive kick. This means the
injector driver is working. Now we can pay attention to the ac-
tual voltage reading. Normal inductive kick voltages vary from
manufacturer to manufacturer. With that said, you can expect
a range from approximately 50 to 80 volts. The important point
here is to compare all the voltage readings from the vehicle’s
injectors. The one that is different from the rest will be revealed.
The lower voltage indicates a weak injector coil or high resis-
tance in the circuit. When cranking the engine it may be neces-
sary to use an extension lead if you do not have a method to
turn the key outside the vehicle
NOTES: Counter mode including pulse width and duty cycle
is not intended for use on fuel injectors. Injector mode will not
provide any usable data on the 12volt supply to the injector. It
is designed to read the fast rapid rise of the inductive kick only.