Acura 3.5 RL Manual page 358

Troubleshooting
Troubleshooting Procedures (cont'd)
Data
Fuel System Loop status is indicated as "open" or "closed".
Loop Status Closed: Based on the HO2S output, the PCM deter-
(Bank 1: Right) mines the air/fuel ratio and controls the amount of
(Bank 2: Left) injected fuel.
Open: Ignoring HO2S output, the PCM refers to signals
from the TP, MAP, and ECT sensors to control the
amount of injected fuel.
The air/fuel ratio correction coefficient for correcting
Short Term
the amount of injected fuel when the Fuel System
Fuel Trim
(Bank 1: Right) Status is "closed". When the signal from the HO2S is
(Bank 2: Left) weak, short term fuel trim gets higher, and the PCM
increases the amount of injected fuel. The air/fuel ratio
gradually gets richer, causing a higher HO2S output.
Consequently, the short term fuel trim is lowered, and
the PCM reduces the amount of injected fuel. This
cycle keeps the air/fuel ratio close to the stoichiometric
ratio when in closed loop status.
Long Term Long term fuel trim in computed from short term fuel
trim and indicates changes occuring in the fuel supply
Fuel Trim
(Bank 1: Right) system over a long period.
(Bank 2: Left) If long term fuel trim is higher than 1.00, the amount of
injected fuel must be increased. If it is lower than 1.00,
the amount of injected fuel must be reduced.
Intake Air The IAT sensor converts intake air temperature into
Temperature voltage and signals the PCM. When intake air tempera-
ture is low, the internal resistance of the sensor
(IAT)
increases, and the voltage signal is higher.
Throttle Based on the accelerator pedal position, the opening
Position
angle of the throttle valve is indicated.
Ignition The ignition advance angle is set by the PCM. The PCM
Timing matches ignition timing to the driving conditions.
Calculated CLV is the engine load calculated from the MAP data.
Load Value
(CLV)
Description Operating Value
At idle speed: closed
-30% - +43%
±20%
With cold engine:
Same as ambient temper-
ature and ECT
At idle: Approx. 10%
At full throttle: Approx.
90%
At idle speed: 15 + 2°
BTDC with the SCS service
connector connected.
At idle speed:
15 - 35%
At 2,500 rpm with no load:
12 - 30%
Freeze Data
YES
YES
YES
YES
YES
NO
YES