Specifications
48
Data Parameters Engine Parameters
between engines and engine wear. Each change in the Long Term Fuel Trim is equivalent to a
change of the Short Term Fuel Trim over its entire range. When the Short Term Fuel Trim
reaches its upper/lower limit, it resets back to the beginning, and moves Long Term Fuel Trim up
or down by one count. The Short Term Fuel Trim continues to move very quickly and if the limits
are reached, it will increment the Long Term Fuel Trim again. This will continue until either the
fuel mixture problem is corrected or long term fuel reaches it limit, causing a DTC to set.
This fine tuning fuel trim correction is also called Additive Mixture Adaptation because it can
modify the duration of injection by adding or subtracting to the base injection time in each fuel
map cell. It thus affects the entire engine speed range or all fuel map cells, but is most noticeable
at idle because of the minimal amount of adjustment capability.
CSO, LOW.P.LOAD F.TRIM CYL 1-3, RIGHT
CSO, LOW.P.LOAD F.TRIM CYL 4-6, RIGHT
CSO, LOW.P.LOAD F.TRIM CYL 7-9, LEFT
CSO, LOW.P.LOAD F.TRIM CYL 10-12, LEFT
Range: ______________________________________________________0.750 to 1.280
Used on ME27 systems. Cylinder shutoff (CSO) mode is used on the V12 engines with separate
bank fuel control. Information on CSO mode is limited, however field technicians believe that if
correct cruise conditions are met, cylinder groups are shut down to conserve fuel. (See the
description for CYLINDER SHUT-OFF 1.) In this mode, mixture adaptation is modified for the
active cylinders, compensating for variations in air mass and pressure ratios. These fuel trim
numbers represent the long term correction to the injection system when the engine is under
partial load and in CSO mode. This number is learned by the ECU and is used to correct small
differences between engines and engine wear. When the short term correction (O2 Integrator) is
outside the window defined in the ECU memory, the long term fuel trim (FTRIM) is changed.
PART LOAD F.TRIM can modify injector duration using a self-adaptation factor. A 1.0 reading
represents the base point. Readings greater than 1.0 indicate that the system is running lean and
to correct—the injection duration is increased. Readings less than 1.0 indicate that the system is
running rich and to correct—the injection duration is decreased.
These parameters display a long-term correction factor applied to the CSO programmed low
partial load base cell values.
CTP (IDLE) ADJUSTMENT VALUE
Range: ______________________________________________________ not available
Used on ME10 and ME20 systems. No information is available at this time.
CTP (IDLE)
CTP (IDLE) CONTACT
CTP (IDLE) INFORMATION
CTP (IDLE) RECOGNITION
Range: _________________________________________________ YES/NO or ON/OFF
Used on DM, DM2, ERE/EVE/ASF (IFI Diesel)), HFM, LH, ME10 and ME20 systems. These
parameters indicate the state of the throttle switch. The display should read YES or ON when the
throttle is closed and NO or OFF when the throttle is open.
CTP (IDLE) LONG-TERM ADAPT. VALUES
Range: ______________________________________________________ not available
Used on ME10 and ME20 systems. No further information is available at this time.
CYL. 1 to 12
Range: __________________________________________________________ ON/OFF
Used on LH, ME10, ME20, systems. These parameters indicate whether or not fuel injector
operation has been suspended to reduce fuel consumption during cruise. The “1 to 12" in the