1996 ACURA RL KA9 Service Repair Manual

Troubleshooting

Troubleshooting Procedures (cont'd)

Data
Description

Operating Value

Freeze Data

Fuel System

Loop Status

(Bank 1: Right)

(Bank 2: Left)
Loop status is indicated as "open" or "closed".

Closed: Based on the HO2S output, the PCM deter-

mines the air/fuel ratio and controls the amount of

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.
At idle speed: closed

YES

Short Term

Fuel Trim

(Bank 1: Right)

(Bank 2: Left)
The air/fuel ratio correction coefficient for correcting

the amount of injected fuel when the Fuel System

Status is "closed". When the signal from the HO2S is

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.
-30%
-
+43%

YES

Long Term

Fuel Trim

(Bank 1: Right)

(Bank 2: Left)
Long term fuel trim in computed from short term fuel

trim and indicates changes occuring in the fuel supply

system over a long period.

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.
±20%

YES

Intake Air

Temperature

(IAT)
The IAT sensor converts intake air temperature into

voltage and signals the PCM. When intake air tempera-

ture is low, the internal resistance of the sensor

increases, and the voltage signal is higher.
With cold engine:

Same as ambient temper-

ature and ECT
YES

Throttle

Position
Based on the accelerator pedal position, the opening

angle of the throttle valve is indicated.
At idle: Approx. 10%

At full throttle: Approx.

90%
YES

Ignition

Timing
The ignition advance angle is set by the PCM. The PCM

matches ignition timing to the driving conditions.
At idle speed: 15 + 2°

BTDC with the SCS service

connector connected.
NO

Calculated

Load Value

(CLV)
CLV is the engine load calculated from the MAP data.

At idle speed:

15
-
35%

At 2,500 rpm with no load:

12
-
30%
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