System Inspection
Engine Control
P0171 System too Lean (Bank 1) - Inspection/Repair:_:System Inspection
System Inspection
Power balance test
Ref.) This test is done when we need to know if the specific cylinder or fuel system causes a problem. We have to do this test under the regular RPM condition.
NOTE:
Move the shift lever to "P" position and operate parking brake before the test.
1. Start engine and keep idle.
2. Set the dual mode with Current data and Actuation test of GDS like below image.
3. Click the "Start" icon and record the engine RPM when the injector stops.
4. Repeat this operation with each injector.
The results of each injector have to be equal in normal condition.
5. Are the RPM of each cylinder almost the same?
Air leak inspection
1. Check the air leakage on intake and exhaust system with below items.
- Damage, bending or bad connection of vacuum pipe
- Damage of throttle body gasket
- Damage of gasket between intake manifold and cylinder head
- Airtightness between injector and intake manifold
- Airtightness between O2 sensor and catalyst
2. Was a problem found?
3. Check the air leakage of purge system as below.
(1) Separate the vacuum pipe connected to intake manifold from canister purge valve.
(2) Input 15 inHg vacuum with vacuum pump into separated pipe.
(3) Is the vacuum kept?
System inspection
1. Perform the visual / physical test as below.
- Inspect that O2 sensor is installed normally or there is a corrosion between sensor and ECM terminal. (Check the wiring is not connected to exhaust side.)
- Check the silicon stain on upstream O2 sensor. It can be found easily by checking the white dust on O2 sensor, and it causes abnormal output.
- Pollution on O2 sensor (by fuel, coolant and engine oil)
- Using unsuitable sealant
2. Check the pollution or performance aggravation of air flow sensor / Bad connection / Wiring damage.
NOTE:
If the stain on O2 sensor or air flow sensor was found, it must be changed with a new component after cleaning the pollution area in order to prevent re-stain.
3. Check the throttle position sensor increases regularly in proportion to acceleration.
4. Check the connection of ECM ground.
5. Repair as necessary and go to "Verification of Vehicle Repair" procedure or Go to next step as below in normal case.
Positive crank case ventilation inspection
1. After you check engine oil, refill or replace it if it is needed.
2. Take a visual inspection about abnormal install of PCV valve or damage of O-ring.
3. Check engine oil is diluted with fuel as below.
(1) Warm up the engine to normal operating temperature.
(2) Set scantool and record the "Lambda Sensor Correction Value" among service data.
(3) After stopping the engine, separate PCV valve from intake manifold and then block the both side with the proper tools.
(4) After restarting the engine, check the "Lambda Sensor Correction Value" again.
Normal status :The measured value before and after removal of PCV has to be constant.
4. Is the measured value within specifications?
Fuel system inspection
Fuel pressure inspection
1. Check water or debris permeate into fuel.
2. Install the fuel pressure gage.
3. Check fuel pressure at idle state.
Normal value :338 - 348kPa (3.45 - 3.55 kg/cm2)
4. Is the measured value within specifications?
Remaining pressure of fuel inspection
1. After stopping the engine, check the fuel pressure fluctuates.
Normal status :after the engine stops, the fuel pressure should be maintained at least for 5 min.
2. Is the measured value within specifications?
