Perkins 1104E Series Troubleshooting Manual page 8

8
Troubleshooting Section
At start-up, the ECM determines the top dead
center position of the number 1 cylinder from the
speed/timing sensor in the fuel injection pump.
The ECM decides when fuel injection should occur
relative to the top dead center position. The ECM
provides the signal to the fuel injection pump spill
valve which stops fuel flow to the low pressure
side. The ECM then forces fuel to flow to the fuel
injector nozzles at the desired time. The ECM adjusts
timing for the best engine performance, the best fuel
economy and the best control of exhaust emissions.
Actual timing cannot be viewed with an electronic
service tool. Also, the desired timing cannot be
viewed with an electronic service tool.
Fuel Injection
The personality module inside the ECM sets certain
limits on the amount of fuel that can be injected. The
FRC Limit is a limit that is based on intake manifold
air pressure and engine rpm. The FRC Limit is used
to control the air/fuel ratio in order to control the
engine's exhaust emissions. When the ECM senses
a higher intake manifold air pressure, the ECM
increases the FRC Limit. A higher intake manifold
air pressure indicates that there is more air in the
cylinder. When the ECM increases the FRC Limit, the
ECM allows more fuel into the cylinder.
The Rated Fuel Limit is a limit that is based on the
power rating of the engine and on the engine rpm.
The Rated Fuel Limit enables the engine power and
torque outputs to conform to the power and torque
curves of a specific engine model.
These limits are in the personality module and these
limits cannot be changed.
Diagnostic Codes
When the ECM detects an engine problem, the ECM
generates a diagnostic code. Also, the ECM logs
the diagnostic code in order to indicate the time of
the problem's occurrence. The ECM also logs the
number of occurrences of the problem. There are
two types of diagnostic fault codes. There are fault
codes and event codes.
Diagnostic Fault Codes
Diagnostic fault codes are provided in order to
indicate that an electrical problem or an electronic
problem has been detected by the ECM. In some
cases, the engine performance can be affected when
the condition that is causing the code exists. More
frequently, the operator cannot detect any difference
in the engine performance.
If the operator indicates that a performance problem
occurs, the diagnostic code may indicate the cause
of the problem. Use either a laptop computer or a
hand held diagnostic tool to access the diagnostic
codes. The problem should then be corrected.
If the operator does not indicate a problem with
the engine performance and a diagnostic code is
logged by the ECM. This situation indicates that
the ECM detected an abnormal engine condition,
but the abnormal condition did not affect engine
performance. In this situation, the system has no
faults except when either of the following conditions
exist:
•
There are several occurrences of the diagnostic
code in a very short period of time.
•
The ECM is indicating an active code at the
present time.
Diagnostic Event Codes
Diagnostic event codes are used to indicate that
some operational problem has been detected in
the engine by the ECM. This does not indicate an
electronic malfunction.
Programmable Parameters
Certain parameters that affect the engine operation
may be changed with electronic service tools.
The parameters are stored in the ECM, and the
parameters are protected from unauthorized changes
by passwords. These parameters are System
Configuration Parameters.
System Configuration Parameters are set at the
factory. System Configuration Parameters affect
emissions or power ratings within the engine. Factory
passwords must be obtained and factory passwords
must be used to change the System Configuration
Parameters.
Passwords
System Configuration Parameters are protected by
factory passwords. Factory passwords are calculated
on a computer system that is available only to
Perkins distributors. Since factory passwords contain
alphabetic characters, only an electronic service
tool may change System Configuration Parameters.
System Configuration Parameters affect the power
rating or the emissions.
Refer to Troubleshooting, "Programming Parameters"
and Troubleshooting, "Factory Passwords".
RENR2696-01