Acura Integra 1998 Service Manual page 243

Troubleshooting
Data
Descriotion
Operating Value
Freeze Data
H O 2 5
Feedback
Loop Status
Loop status is indicated as
"open" or "closed".
Closed: Based on the H02S output, the ECM deter-
mines the airlfuel ratio and controis the amount of
iniected fuel.
Open: lgnoring HO2S output, the ECM refers to sig-
nals from the TP, MAP, and ECT sensors to control
the amount of iniected fuel.
Al idle speed: closed
Y E S
Short Term
Fuel Trim
The airlfuel ratio correclion coeificient lor correcting
the amount ol iniected fuel when HO2S feedback is in
the closed loop status. When the signal from the
HO2S is weak, short term fuel trim gets highef. and
the ECM increases the amount of injected fuel The
airlfuel ratio gradually gets richer, causing a higher
HO2S output.
Consequentlv, the short term fuel trim is lowered, and
the ECM reduces the amount of injected tuel. This
cycle keeps the airlfuel ratio close to the stoichiomeric
ratio when in closed loop status.
-30o/" - + 41%
YES
Term
T r i m
Long
F u e l
Long term fuel trim in computed trom short term fuel
trim and indicates changes occurring in the fuel sup-
ply system over a long period.
l f l o n g t e r m f u e l t r i m i s h i g h e r t h a n 1 . 0 0 , t h e a m o u n t
of injected fuel must be increased. ll it is lower than
1.00, the amount of iniected fuel must be reduced
-14% - + 2Oo/"
Y E S
lntake Air
Temperature
(rAT)
The IAT sensor converts intake air temperature into
voltage and signals the ECM. When intake air temper-
ature 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
anole of the throttle valve is indicated.
Ar idle: Approx. 107o
At full throttle: Approx.
90%
YES
l g n i t i o n
T i m i n g
The ignition advance angle is set by the ECM. The
EClvl matches ignition timing to the driving condi-
t i o n s .
At idle speed: 16 t 2'
BTDC with the SCS ser-
vice connector connected.
N O
Calculated
Load Value
(CLV)
CLV is the engine load calculated from the MAP data.
At idle speedi
15 - 35%
At 2,500 rpm with no load:
12 - 30./.
YES
-3 8