System Inspection

System Inspection

Check intake/exhaust system for restriction or leakage
1. Visually/physically inspect the air leakage in intake/exhaust system as following items.
Vacuum hoses for splits, kinks and improper connections.
Throttle body gasket.
Gasket between intake manifold and cylinder head.
Seals between intake manifold and fuel injectors.
Exhaust system between HO2S and Three way catalyst for air leakage.
2. Visually/physically inspect the restriction in intake/exhaust system as following items.
Air cleaner filter element for excessive dirt or for any foreign objects.
Throttle body inlet for damage or for any foreign objects.
Throttle bore, throttle plate and the IAC passages for chocking and for any foreign objects.
Restricted exhaust system.
3. Was a problem found in any of the above areas ?
YES
1) Replace or repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
1) Go to " Check the engine oil contamination " procedure.
Check the engine oil contamination
1. Check the engine oil level. The oil level should be between the min. and max. marking. Fill to the correct oil level.
2. Warm up the engine to normal operating temperature
3. Connect Scantool and note the "SHORT TERM FUEL-B1" parameter on the Scantool data list.
4. Disconnect and plug the positive crankcase ventilation.
5. Monitor the "SHORT TERM FUEL-B1" parameter on the Scantool data list once again.
Specification : The value should remain more or less unchanged
6. Is the displayed value within the specified value ?
YES
1) Go to "Sensor Contamination Inspection" procedure.
NO
1) The engine oil is diluted with fuel. Change the oil and oil filter and go to "Verification of Vehicle Repair" procedure.
Sensor Contamination Inspection
1. Visually/physically inspect following items:
Remove and inspect the HO2S (B1S1) for any silicon contamination. This contamination will be indicated by a white powdery coating and this will result in a but false voltage signal
Check MAFS for contamination, deterioration or damage.
If contamination is evident on the HO2S or MAFS, replace contaminated sensor and go to next step.
Check for Leakage in EVAP System
1. Check the EVAP. EM system for possible over.
(1) Remove the manifold side vacuum hose from the EVAP canister purge valve.
(2) Using a hand vacuum pump apply specified vacuum (Approx. 15 in, Hg) to the manifold side of the valve.
(3) Does the valve hold vacuum ?
YES
1) Go to "Fuel System Inspection" procedure
NO
1) Repair air leakage and go to "Verification of Vehicle Repair" procedure.
Fuel System Inspection
1. Check the fuel for excessive water, alcohol or other contaminants. Replace contaminated fuel as necessary.
2. Install a fuel pressure gage.
3. Start engine and let it idle. With the vacuum hose from the fuel pressure regulator disconnected, inspect fuel pressure.
Specification : 343 kPa (3.5 kg/cm2, 49.8 psi)
4. Is fuel pressure within the specification ?
YES
1) Go to "Fuel Injector Inspection" procedure as below
NO
1) Repair as necessary refer to inspection note as below and go to "Verification of Vehicle Repair" procedure. (Inspection Note)

CAUTION:
1) Check if fuel line pressure decreases when accelerating quickly.
1) If it does, check fuel pump maximum pressure. If pressure is OK, check fuel line and filter for clogging
2) If fuel pressure is lower than Specification : Check for fuel line pressure while pinching fuel return hose.
1) If pressure quickly increases, check pressure regulator
2) If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure.
3) If fuel pressure is higher than Specification : Is fuel line clogged ?
1) If it is not, replace pressure regulator.
2) If it is, replace it.

Fuel Injector Inspection
1. Check the fuel injectors for clogging or any restrictions.
Test Condition : Ignition "OFF".
Specification : No clogging and restriction.
2. Is the fuel injector OK ?
YES
1) Visually/physically inspect the engine mechanical problem. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
1) Check injector for contamination, deterioration or damage. Substitute with a known-good injector and check for proper operation. If the problem is corrected, replace injector and then go to "Verification of Vehicle Repair" procedure.