Inspection and Verification - Engine Performance
Note. There are 2 diagnostic paths that can be followed depending on the type of engine concern. Carry out INSPECTION AND VERIFICATION - ENGINE PERFORMANCE or INSPECTION AND VERIFICATION - NVH .
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical or electrical damage.
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- NOTE: Make sure to use the latest scan tool software release. If the cause is not visually evident, connect the scan tool to the DLC .
- NOTE: The VCM LED prove out confirms power and ground from the DLC are provided to the VCM . If the scan tool does not communicate with the VCM : check the VCM connection to the vehicle. check the scan tool connection to the VCM . check for No Power To The Scan Tool, to diagnose no power to the scan tool. REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) .
- If the scan tool does not communicate with the vehicle: verify the ignition key is in the ON position. verify the scan tool operation with a known good vehicle. to diagnose no response from the PCM , REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) .
- Carry out the network test. If the scan tool responds with no communication for one or more modules, REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) . If the network test passes, retrieve and record continuous memory DTCs.
- Clear the continuous DTCs and carry out the self-test diagnostics for the Battery Control Module (BCM) - High Voltage Traction Battery (HVTB) and PCM .
- If the DTCs retrieved are related to the concern, go to the Battery Control Module (BCM) - High Voltage Traction Battery (HVTB) DTC Chart. REFER to: «HIGH VOLTAGE BATTERY, MOUNTING AND CABLES - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635195-S00394178412014070200000) . For all other DTCs, REFER to: «ELECTRONIC ENGINE CONTROLS - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635205-S24896621602014070200000) .
- If no DTCs related to the concern are retrieved, GO to «SYMPTOM CHART - ENGINE PERFORMANCE»(ref-635246-S36504016662014070200000) .
Inspection and Verification - NVH
- NVH symptoms should be identified using the diagnostic tools and techniques that are available. For a list of these techniques, tools, an explanation of their uses and a glossary of common terms, REFER to: «NOISE, VIBRATION AND HARSHNESS (NVH)»(ref-635210-S41736656702014070200000) . Since it is possible that any one of multiple systems may be the cause of the symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system.
- Verify the customer concern by operating the engine to duplicate the condition.
- Check the engine oil level and check the oil for contamination. Low engine oil level or contaminated oil are a common cause of engine noise. If the oil is contaminated, the source of the contamination must be identified and repaired as necessary.
- Visually inspect for obvious signs of mechanical damage.
- If the inspection reveals obvious concerns that can be readily identified, repair as necessary.
- NOTE: Make sure to use the latest scan tool software release. If the cause is not visually evident, connect the scan tool to the DLC .
- NOTE: The VCM LED prove out confirms power and ground from the DLC are provided to the VCM . If the scan tool does not communicate with the VCM : check the VCM connection to the vehicle. check the scan tool connection to the VCM . check for No Power To The Scan Tool, to diagnose no power to the scan tool. REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) .
- If the scan tool does not communicate with the vehicle: verify the ignition key is in the ON position. verify the scan tool operation with a known good vehicle. to diagnose no response from the PCM , REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) .
- Carry out the network test. If the scan tool responds with no communication for one or more modules, REFER to: «COMMUNICATIONS NETWORK»(ref-635190-S21431355752014070200000) . If the network test passes, retrieve and record continuous memory DTCs.
- Clear the continuous DTCs and carry out the self-test diagnostics for the BCM-HVTB and PCM .
- If the DTCs retrieved are related to the concern, go to the Battery Control Module (BCM) - High Voltage Traction Battery (HVTB) DTC Chart. REFER to: «HIGH VOLTAGE BATTERY, MOUNTING AND CABLES - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635195-S00394178412014070200000) . For all other DTCs, REFER to: «ELECTRONIC ENGINE CONTROLS - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV)»(ref-635205-S24896621602014070200000) .
- If no DTCs related to the concern are retrieved, continue the inspection and verification if a noise concern is related to the engine. For vibration concerns and noise concerns such as powertrain mounts, air intake system and starter GO to «SYMPTOM CHART - NVH»(ref-635246-S29457382862014070200000) . In some cases, a noise may be a normal characteristic of that engine type. In other cases the noise may require further investigation. Comparing the noise to a similar year/model vehicle equipped with the same engine will aid in determining if the noise is normal or abnormal. Once a customer concern has been identified as an abnormal engine noise, it is critical to determine the location of the specific noise. Use the EngineEAR/ChassisEAR or stethoscope (the noise will always be louder closer to the noise source) to isolate the location of the noise to one of the following areas. Fuel injector(s) Upper end of engine Lower end of engine Front of engine Rear of engine
Symptom Chart - Engine Performance
| Symptom | Possible Sources | Action |
|---|---|---|
| Difficult starting | Inoperative or damaged ignition system Air or vacuum leak Inoperative or damaged fuel system Inoperative or damaged starting system | Refer to the appropriate engine article for the procedure. Refer to INTRODUCTION - HYBRID . |
| Damaged charging system/battery | REFER to: DIRECT CURRENT/DIRECT CURRENT (DC/DC) CONVERTER CONTROL MODULE - HYBRID ELECTRIC VEHICLE (HEV) . | |
| Burnt valve | INSTALL a new cylinder head. TEST the system for normal operation after the repair. | |
| Worn piston | INSTALL a new piston. TEST the system for normal operation after the repair. | |
| Worn piston rings | INSTALL new piston rings. TEST the system for normal operation after the repair. | |
| Worn cylinder | INSTALL a new cylinder block. TEST the system for normal operation after the repair. | |
| Damaged head gasket | INSTALL a new cylinder head gasket. TEST the system for normal operation after the repair. | |
| Inoperative or damaged cooling system | Refer to the appropriate engine article for the procedure. | |
| Fail-safe cooling invoked (if equipped) | Refer to INTRODUCTION - HYBRID . | |
| Poor idling | Vacuum leaks Inoperative or damaged EGR system | Refer to the appropriate engine article for the procedure. Refer to INTRODUCTION - HYBRID . |
| Inoperative or damaged ignition system | Refer to the appropriate engine article for the procedure. | |
| Inoperative or damaged cooling system Inoperative or damaged fuel system | Refer to the appropriate engine article for the procedure. | |
| Fail-safe cooling invoked (if equipped) | Refer to INTRODUCTION - HYBRID . | |
| Incorrect valve clearance | ADJUST valve clearance. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Incorrect valve-to-valve seat contact | INSTALL a new cylinder head. TEST the system for normal operation after the repair. | |
| Damaged head gasket | INSTALL a new cylinder head gasket. TEST the system for normal operation after the repair. | |
| Engine runs rough | Inoperative or damaged fuel system Air or vacuum leaks EGR system fault Inoperative or damaged cooling system Inoperative or damaged ignition system | Refer to the appropriate engine article for the procedure. |
| Fail-safe cooling invoked (if equipped) | Refer to INTRODUCTION - HYBRID . | |
| Burnt or sticking valve | INSTALL a new valve. TEST the system for normal operation after the repair. | |
| Weak or broken valve spring | INSTALL a new valve spring. TEST the system for normal operation after the repair. | |
| Carbon accumulation in combustion chamber | ELIMINATE carbon buildup. TEST the system for normal operation after the repair. | |
| Excessive oil consumption | Leaking oil | REPAIR oil leakage. TEST the system for normal operation after the repair. |
| Damaged or collapsed air intake hoses and tubes | Tighten hoses clamps. INSPECT for damage and REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Damaged exhaust or exhaust leaks at turbocharger housing or exhaust manifold. | INSPECT for leaks. Leaks can be detected audibility or visually, by a discoloration caused by escaping hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Inoperative PCV system | REPAIR or INSTALL new components as necessary. TEST the system for normal operation after the repair. | |
| Incorrect oil | CHANGE oil to correct specification. TEST the system for normal operation after the repair. | |
| Worn valve stem seal | INSTALL a new valve stem seal. TEST the system for normal operation after the repair. | |
| Worn valve stem or valve guide | INSTALL a new cylinder head. TEST the system for normal operation after the repair. | |
| Sticking piston rings | INSTALL new piston rings. TEST the system for normal operation after the repair. | |
| Worn piston ring groove | INSTALL a new piston and piston pin. TEST the system for normal operation after the repair. | |
| Worn piston or cylinder | INSTALL a new piston or cylinder block. TEST the system for normal operation after the repair. | |
| Oil in coolant | Leaking head gasket Damaged cylinder block Damaged cylinder head | INSPECT the engine components. INSTALL new engine components as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Coolant in oil | Leaking head gasket Damaged cylinder block Damaged cylinder head | INSPECT the engine components. INSTALL new engine components as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Insufficient power | Inoperative or damaged ignition system Air intake system blockage Lubrication system blockage Inoperative or damaged fuel system | Refer to the appropriate engine article for the procedure. Refer to INTRODUCTION - HYBRID . |
| Damaged exhaust or exhaust leaks at turbocharger housing or exhaust manifold | INSPECT for leaks. Leaks can be detected audibility or visually, by a discoloration caused by escaping hot exhaust gases. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Oil level too high | DRAIN oil to correct level. | |
| Incorrect engine oil | INSTALL correct specification engine oil. TEST the system for normal operation after the repair. | |
| Excessive accessory drive belt loading Inoperative or damaged cooling system | Refer to the appropriate engine article for the procedure. | |
| Fail-safe cooling invoked (if equipped) | Refer to INTRODUCTION - HYBRID . | |
| Damaged or plugged exhaust system | INSPECT exhaust system. TEST the system for normal operation after the repair. | |
| Incorrect tire size | REFER to: SUSPENSION SYSTEM . | |
| Dragging brakes | REFER to: BRAKE SYSTEM . | |
| Slipping transmission | Refer to the appropriate transmission article for the procedure. | |
| Incorrect valve clearance | ADJUST valve clearance. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Worn or damaged valve tappet | INSTALL a new valve tappet. TEST the system for normal operation after the repair. | |
| Damaged valve guide Compression leakage at valve seat Seized valve stem | INSTALL a new cylinder head assembly. TEST the system for normal operation after the repair. | |
| Weak or broken valve spring | INSTALL a new valve spring. TEST the system for normal operation after the repair. | |
| Worn or damaged cam | INSTALL a new camshaft. TEST the system for normal operation after the repair. | |
| Damaged head gasket | INSTALL a new head gasket. TEST the system for normal operation after the repair. | |
| Cracked or distorted cylinder head | INSTALL a new cylinder head assembly. TEST the system for normal operation after the repair. | |
| Damaged, worn or sticking piston ring(s) | INSTALL a new piston ring(s). TEST the system for normal operation after the repair. | |
| Worn or damaged piston | INSTALL a new piston and piston pin. TEST the system for normal operation after the repair. | |
| Engine emits excessive black smoke (black/blue/white) | Clogged Air Cleaner (ACL) element | INSTALL a new ACL element. TEST the system for normal operation after the repair. |
| Incorrect type or grade of oil | DRAIN and FILL with specified oil. | |
| Engine wear (piston rings, valve guides) | REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Plugged crankcase ventilation system | Visually INSPECT the crankcase ventilation system. |
SYMPTOMS DESCRIPTIONS
Symptom Chart - NVH
| Symptom | Possible Sources | Action |
|---|---|---|
| Drone type noise | Powertrain mount(s) | CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. REFER to: POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING . TEST the system for normal operation after the repair. |
| Drumming noise - occurs inside the vehicle during idle or high idle, hot or cold. Very low-frequency drumming is very RPM dependent | Engine vibration excites the body resonances inducing interior noise | CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. REFER to: POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING . TEST the system for normal operation after the repair. |
| Engine drumming noise - accompanied by vibration | Powertrain mount(s) | CARRY OUT the Powertrain/Drivetrain Mount Neutralizing procedure. REFER to: POWERTRAIN/DRIVETRAIN MOUNT NEUTRALIZING . TEST the system for normal operation after the repair. |
| Rattle - occurs at idle or at light acceleration from a stop | Powertrain mount(s) | CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to the appropriate engine article for the procedure. For transaxle, Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. |
| Whine/moan type noise - pitch increases or changes with vehicle speed | Powertrain mount(s) | CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to the appropriate engine article for the procedure. For transaxle, Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. |
| Clunk - occurs when shifting from PARK or between REVERSE and DRIVE | Powertrain mounts | CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to the appropriate engine article for the procedure. For transaxle, Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. |
| Idle speed is too high | CHECK for the correct idle speed. TEST the system for normal operation after the repair. | |
| Accessory drive bearing hoot - occurs at idle or high idle in cold temperatures of approximately 4°C (40°F) or colder at the first start of the day | Accessory drive idler or tensioner pulley bearing is experiencing stick/slip between ball bearings and the bearing race | CARRY OUT the Engine Cold Soak procedure. REFER to: NOISE, VIBRATION AND HARSHNESS (NVH) . PLACE the EngineEAR probe directly on the idler/tensioner center post or bolt to verify which bearing is making the noise. INSTALL new parts as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Accessory drive belt noise, squeal or chirping | Defective/worn or incorrect accessory drive belt Misaligned pulley(s) Pulley runout Damaged or worn accessory drive component or idler Fluid contamination of the accessory drive belt or pulleys Damaged or worn accessory drive belt tensioner Damaged pulley grooves | CARRY OUT the Engine Accessory Test. REFER to: NOISE, VIBRATION AND HARSHNESS (NVH) . INSPECT components and INSTALL new parts as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Clunking noise | Coolant pump has excessive end play or imbalance | CHECK the coolant pump for excessive end play. INSPECT the coolant pump for imbalance with the drive belt off. INSTALL a new coolant pump as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Whine or moaning noise | Air intake system | CHECK the air cleaner and ducts for correct fit. INSPECT the air intake system for leaks or damage. REPAIR as necessary. TEST the system for normal operation after the repair. |
| Whistling noise - normally accompanied with poor idle condition | Air intake system | CHECK the air intake ducts, air cleaner, throttle body and vacuum hoses for leaks and correct fit. REPAIR or ADJUST as necessary. TEST the system for normal operation after the repair. |
| Loose connections or damage to air intake hoses and tubes | TIGHTEN hose clamps. INSPECT for damage and REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Hissing noise - occurs during idle or high idle that is apparent with the hood open | Vacuum leak | Use the Ultrasonic Leak Detector/EngineEAR to locate the source. Scan the air intake system from the inlet to each cylinder intake port. DISCARD the leaking parts, and INSTALL a new component. TEST the system for normal operation after the repair. |
| Vehicles with a plastic intake manifold | Acceptable condition. Some plastic manifolds exhibit this noise, which is the effect of the plastic manifold. | |
| Grinding noise - occurs during engine cranking | Incorrect starter motor mounting | INSPECT the starter motor for correct mounting. REPAIR as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Starter motor | CHECK the starter motor. INSTALL a new starter motor as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Incorrect starter motor drive engagement | INSPECT the starter motor drive for wear or damage. INSTALL a new starter motor as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. INSPECT the flywheel/flexplate for wear or damage. INSTALL a new flywheel/flexplate as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Engine noise, front of engine - knocking noise from lower front of engine | Damaged or separated crankshaft pulley/damper | CHECK for obvious signs of damage or wobble during operation. INSTALL new as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, front of engine - ticking, tapping or rattling noise from the front of the engine | Timing drive components | REMOVE the accessory drive belt. Refer to the appropriate engine article for the procedure. USE the EngineEAR to isolate the noise to the engine front cover. REMOVE the engine front cover and INSPECT the timing drive components. INSTALL new parts as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, upper end - ticking noise near the fuel rail and intake manifold | Fuel rail clip Fuel injector | CHECK for loose or damaged fuel rail clip(s). REPAIR as necessary. USE the EngineEAR to isolate the noisy injector(s). INSTALL a new injector(s) as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, upper end - ticking, knocking or rattle noise that occurs during idle or high idle during the first cold start of the day and may disappear as the engine warms | Valve train noise (bled down lifter/lash adjuster) | CARRY OUT the VALVE TRAIN ANALYSIS COMPONENT TEST . INSTALL new parts as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, upper end - occurs mostly with a warm engine at light/medium acceleration | Worn or damaged spark plugs | REMOVE the spark plugs. INSPECT and INSTALL new as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, upper end - rattling noise from the valve train. Worse when the engine is cold | Low oil level | CHECK the oil level. FILL as necessary. |
| Thin or diluted oil | INSPECT the oil for contamination. If the oil is contaminated, CHECK for the source. REPAIR as necessary. CHANGE the oil and filter. TEST the system for normal operation after the repair. | |
| Low oil pressure | CARRY OUT the OIL PRESSURE TEST . If not within specifications, REMOVE the engine oil pan. Refer to the appropriate engine article for the procedure. INSPECT for a blocked oil pick up tube. TEST the system for normal operation after the repair. | |
| Worn valve train components | CARRY OUT the VALVE TRAIN ANALYSIS COMPONENT TEST . INSTALL new parts as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Worn valve guides | CARRY OUT the VALVE GUIDE INNER DIAMETER procedure. REFER to: VALVE GUIDE INNER DIAMETER . | |
| Excessive runout of the valve seats on the valve face | INSPECT for abnormalities on the valve face and valve seat. INSTALL a new cylinder head assembly if abnormalities are found. | |
| Engine noise, upper end - pinging noise | Gasoline octane too low | VERIFY with customer the type of gasoline used. CORRECT as necessary. TEST the system for normal operation after the repair. |
| KS operation | CHECK the KS operation. INSTALL a new KS . Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Incorrect spark timing | CHECK the spark timing. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| High operating temperature | INSPECT the cooling system for leaks. CHECK the coolant level. REFILL as necessary. CHECK the coolant for the correct mix ratio. DRAIN and REFILL as needed. VERIFY the engine operating temperature is within specifications. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Spark plug | CHECK the spark plugs. REPAIR or INSTALL new spark plugs as necessary. TEST the system for normal operation after the repair. | |
| Catalytic converter | Compare with a similar vehicle for what is acceptable noise. | |
| Engine noise, lower end - ticking or knocking noise near the oil filter adapter | Oil pump | USE the EngineEAR to verify the oil pump as the source of the noise at low RPM. REPAIR as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine noise, lower end - light knocking noise, also described as piston slap. Noise is most noticeable when the engine is cold with light to medium acceleration. The noise disappears as the engine warms | Excessive clearance between the piston and the cylinder wall | CARRY OUT the PISTON DIAMETER procedure. REFER to: PISTON DIAMETER . Measure the cylinder bore diameter. Subtract the piston diameter from the cylinder bore diameter to find the piston-to-cylinder bore clearance. REFER to the appropriate engine article for specifications. |
| Engine noise, lower end - light double knock or sharp rap sound. Occurs mostly with a warm engine at idle or low speeds in drive. Increases in relation to engine load. Associated with a poor lubrication history | Excessive clearance between the piston and the piston pin | MEASURE the piston pin bore and the piston pin in 2 directions on each side. REFER to the appropriate engine article for specifications. |
| Engine noise, lower end - light knocking noise. The noise is most noticeable when the engine is warm. The noise tends to decrease when the vehicle is coasting or in neutral | Excessive clearance between the connecting rod bearings and the crankshaft | CARRY OUT the CONNECTING ROD BEARING JOURNAL CLEARANCE procedure. REFER to: CONNECTING ROD BEARING JOURNAL CLEARANCE . |
| Engine noise, lower end - deep knocking noise. The noise is most noticeable when the engine is warm, at lower RPM and under a light load and then at float | Worn or damaged crankshaft main bearings | CARRY OUT the CRANKSHAFT MAIN BEARING JOURNAL CLEARANCE procedure. REFER to: CRANKSHAFT MAIN BEARING JOURNAL CLEARANCE . |
| Engine noise, rear of engine - knocking noise at rear of engine | Damaged flywheel/flexplate | INSPECT the flywheel/flexplate for wear or damage. INSTALL a new flywheel/flexplate as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine vibration - vibration felt at all times | Excessive engine pulley runout | CARRY OUT the Engine Accessory Test. REFER to: NOISE, VIBRATION AND HARSHNESS (NVH) . INSTALL a new engine pulley as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Damaged or worn accessory component | CARRY OUT the Engine Accessory Test. REFER to: NOISE, VIBRATION AND HARSHNESS (NVH) . REPAIR or INSTALL a new component as necessary. TEST the system for normal operation after the repair. | |
| Engine vibration - at idle, a low-frequency vibration (5-20 Hz) or mild shake that is felt through the seat/floorpan | Cylinder misfire | Using the scan tool, CARRY OUT the cylinder power balance and the relative compression test. REPAIR as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine or torque converter out of balance | VERIFY the torque converter to crankshaft pilot clearance is correct. REPAIR as necessary. RE-INDEX the torque converter on the flex plate by 120 degrees for a 3-bolt converter or 180 degrees for a 4-bolt converter. Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. | |
| Engine vibration - is felt with increases and decreases in engine RPM | Powertrain mount(s) | CHECK the powertrain mounts for damage. INSTALL new mounts as necessary. For engine, Refer to the appropriate engine article for the procedure. For transaxle, Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. |
| Engine or transmission grounded to chassis | INSPECT the powertrain/drivetrain for correct clearances. REPAIR as necessary. TEST the system for normal operation after the repair. | |
| Engine vibration - increases intensity as the engine RPM is increased | Engine out-of-balance | CARRY OUT the NERU Test. REFER to: NOISE, VIBRATION AND HARSHNESS (NVH) . ROTATE the torque converter, 120 degrees for 3-bolt or 180 degrees for 4-bolt. INSPECT the torque converter pilot outer diameter-to-crankshaft pilot inner diameter. REPAIR as necessary. Refer to the appropriate transmission article for the procedure. TEST the system for normal operation after the repair. |
| Engine vibration - mostly at coast/neutral coast. Condition improves with vehicle acceleration | Combustion instability | CHECK the ignition system. INSTALL new components as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Engine vibration or shudder - occurs with light to medium acceleration above 56 km/h (35 mph) | Worn or damaged spark plugs | INSPECT the spark plugs for cracks, high resistance or broken insulators. INSTALL a new spark plug(s) as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. |
| Plugged fuel injector | REPAIR or INSTALL a new injector as necessary. Refer to the appropriate engine article for the procedure. TEST the system for normal operation after the repair. | |
| Contaminated fuel | INSPECT the fuel for contamination. DRAIN the fuel system and refill. TEST the system for normal operation after the repair. |
SYMPTOMS DESCRIPTIONS
Compression Test - Hybrid
The compression test requires cranking the engine a minimum of 5 compression strokes with the throttle plate in the wide-open position for each cylinder. The engine cranking diagnostic mode must be used to crank the engine and the brake/accelerator pedals must be used to position the throttle plate during the compression test. The engine cranking diagnostic mode is a PCM strategy which is separate from the normal operating strategy. It allows the engine to crank in a similar fashion as a conventional vehicle with the fuel disabled. When in this mode, the PCM commands the TCM to spin the generator, which cranks the engine with the speed between 900 and 1, 200 RPM. The engine will crank as long as the traction battery state of charge stays greater than 35%.
- Make sure the oil in the crankcase is of the correct viscosity and at the correct level. Operate the vehicle until the engine is at normal operating temperature.
- Using the VCM , access the Battery Control Module (BCM) - High Voltage Traction Battery (HVTB) and monitor the traction battery state of charge PID . If the monitored PID displays the state of charge below 45%, start and idle the engine with full A/C ON. When the traction battery state of charge exceeds 45%, the engine cranking diagnostic mode can be activated.
- Turn the ignition switch to the OFF position, then remove all the spark plugs.
- Install a compression gauge such as the Quick Disconnect Compression Tester in the No. 1 cylinder.
- Activate the cranking diagnostic mode as follows: Apply the parking brake. Place the gear selector in the PARK position. Verify the key is in the OFF position. NOTE: Do not crank the engine. Turn the key to the ON position with the engine OFF. Within 5 seconds of the key in the ON position, fully apply the accelerator pedal and hold for 10 seconds. Within 5 seconds release the accelerator pedal, shift the gear selector to the NEUTRAL position and fully apply the accelerator pedal. Hold the accelerator pedal fully applied for 10 seconds. Release the accelerator pedal and shift the gear selector to the PARK position. If the sequence is correctly executed, the Instrument Cluster (IC) hazard indicator (red triangle) flashes once per second when the gear selector is shifted to the PARK position. The PCM exits the engine cranking diagnostic mode when the traction battery state of charge drops below 35%, the gear selector is shifted to any gear other than PARK or when the ignition key is turned to the OFF or ACC position.
- NOTE: If the ignition key stays in the START position for 15 seconds or longer, the PCM may set DTC P2535. NOTE: If the brake pedal is not depressed and held prior to depressing the accelerator pedal, the throttle plate will fail to open. Crank the engine as follows: Depress and hold the brake pedal. Fully depress and hold the accelerator pedal. Turn the key to the START position and crank the engine a minimum of 5 compression strokes and record the highest reading. Return the key to the ON position. Release the accelerator pedal. Release the brake pedal.
- Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
- Position the key to the OFF position to deactivate the cranking diagnostic mode.
- Clear all DTCs.
Compression Test - Test Results
The indicated compression pressures are considered within specification if the lowest reading cylinder is at least 75% of the highest reading. Refer to the COMPRESSION PRESSURE LIMIT CHART .
Compression Test - Interpreting Compression Readings
- If compression improves considerably, piston rings are worn or damaged.
- If compression does not improve, valves are sticking or not seating correctly.
- If 2 adjacent cylinders indicate low compression pressures and squirting oil on each piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil or coolant in cylinders could result from this condition. Use the Compression Pressure Limit Chart when checking cylinder compression so the lowest reading is within 75% of the highest reading.
Oil Consumption Test
- NOTE: Once all of the previous conditions are met, carry out an «OIL CONSUMPTION TEST»(ref-635246-S09572646432014070200000) . Drain the engine oil and remove the oil filter. Install a new manufacturer-specified oil filter. Make sure the vehicle is positioned on a level surface. Refill the oil pan to a level 0.85 liter (0.90 quart) less than the specified fill level, using manufacturer-specified oil.
- Run the engine for 3 minutes (if hot) or 10 minutes (if cold). Allow for a minimum 5-minute drainback period and then record the oil level shown on the oil level indicator. Place a mark on the backside of the oil level indicator noting the oil level location.
- Add the final 0.85 liter (0.90 quart) to complete the normal oil fill. Restart the engine and allow it to idle for 2 minutes. Shut the engine down.
- After a 5-minute drainback period, record the location of the oil level again. Mark the oil level indicator with the new oil level location. NOTE: Both marks should be very close to the MIN-MAX upper and lower limits or the upper and lower holes on the oil level indicator. These marks will exactly measure the engine's use of oil, with a one quart differential between the new marks. Demonstrate to the customer that the factory-calibrated marks on the oil level indicator are where the oil should fall after an oil change with the specified fill amount. Explain however, that this may vary slightly between MIN-MAX or the upper and lower holes on the oil level indicator.
- Record the vehicle mileage.
- Advise the customer that oil level indicator readings must be taken every 320 km (200 mi) or weekly, using the revised marks as drawn. Remind the customer that the engine needs a minimum 5-minute drainback for an accurate reading and that the oil level indicator must be firmly seated in the tube prior to taking the reading.
- When the subsequent indicator readings demonstrate a 0.85 liter (0.90 quart) has been used, record the vehicle mileage. The mileage driven should not be less than 2, 414 km (1, 500 mi). The drive cycle the vehicle has been operated under must be considered when making this calculation. It may be necessary to have the customer bring the vehicle in for a periodic oil level indicator reading to closely monitor oil usage.
Intake Manifold Vacuum Test
Bring the engine to normal operating temperature. Connect the Vacuum/Pressure Tester to the intake manifold. Run the engine at the specified idle speed.
The vacuum gauge should read between 51-74 kPa (15-22 in-Hg) depending upon the engine condition and the altitude at which the test is conducted. Subtract 4.0193 kPa (1 in-Hg) from the specified reading for every 304.8 m (1, 000 feet) of elevation above sea level.
The reading should be steady. If necessary, adjust the gauge damper control (where used) if the needle is fluttering rapidly. Adjust the damper until the needle moves easily without excessive flutter.
Intake Manifold Vacuum Test - Interpreting Vacuum Gauge Readings
A careful study of the vacuum gauge reading while the engine is idling will help pinpoint trouble areas. Always conduct other appropriate tests before arriving at a final diagnostic decision. Vacuum gauge readings, although helpful, must be interpreted carefully.
Most vacuum gauges have a normal band indicated on the gauge face. The following are potential gauge readings. Some are normal; others should be investigated further.
The following are potential gauge readings. Some are normal; others should be investigated further.
- NORMAL READING: Needle between 51-74 kPa (15-22 in-Hg) and holding steady.
- NORMAL READING DURING RAPID ACCELERATION AND DECELERATION: When the engine is rapidly accelerated (dotted needle), the needle will drop to a low reading (not to zero). When the throttle is suddenly released, the needle will snap back up to a higher than normal figure.
- NORMAL FOR HIGH-LIFT CAMSHAFT WITH LARGE OVERLAP: The needle will register as low as 51 kPa (15 in-Hg) but will be relatively steady. Some oscillation is normal.
- WORN RINGS OR DILUTED OIL: When the engine is accelerated (dotted needle), the needle drops to 0 kPa (0 in-Hg). Upon deceleration, the needle runs slightly above 74 kPa (22 in-Hg).
- STICKING VALVES: When the needle (dotted) remains steady at a normal vacuum but occasionally flicks (sharp, fast movement) down and back about 13 kPa (4 in-Hg), one or more valves may be sticking.
- BURNED OR WARPED VALVES: A regular, evenly-spaced, downscale flicking of the needle indicates one or more burned or warped valves. Insufficient valve clearance will also cause this reaction.
- POOR VALVE SEATING: A small but regular downscale flicking can mean one or more valves are not seating.
- WORN VALVE GUIDES: When the needle oscillates over about a 13 kPa (4 in-Hg) range at idle speed, the valve guides could be worn. As engine speed increases, the needle will become steady if guides are responsible.
- WEAK VALVE SPRINGS: When the needle oscillation becomes more violent as engine RPM is increased, weak valve springs are indicated. The reading at idle could be relatively steady.
- LATE VALVE TIMING: A steady but low reading could be caused by late valve timing.
- IGNITION TIMING RETARDING: Retarded ignition timing will produce a steady but somewhat low reading.
- INSUFFICIENT SPARK PLUG GAP: When spark plugs are gapped too close, a regular, small pulsation of the needle can occur.
- INTAKE LEAK: A low, steady reading can be caused by an intake manifold or Throttle Body (TB) gasket leak.
- BLOWN HEAD GASKET: A regular drop of fair magnitude can be caused by a blown head gasket or warped cylinder head-to-cylinder block surface.
- RESTRICTED EXHAUST SYSTEM: When the engine is first started and is idled, the reading may be normal, but as the engine RPM is increased, the back pressure caused by a clogged muffler, kinked tailpipe or other concerns will cause the needle to slowly drop to 0 kPa (0 in-Hg). The needle then may slowly rise. Excessive exhaust clogging will cause the needle to drop to a low point even if the engine is only idling.
When vacuum leaks are indicated, search out and correct the cause. Excess air leaking into the system will upset the fuel mixture and cause concerns such as rough idle, missing on acceleration or burned valves. If the leak exists in an accessory unit such as the power brake booster, the unit will not function correctly. Always fix vacuum leaks.
Oil Pressure Test
- Disconnect and remove the EOP switch from the engine.
- Connect the EOP Gauge to the oil pressure sender oil galley port.
- Run the engine until normal operating temperature is reached.
- Run the engine at the specified RPM and record the gauge reading.
- The oil pressure should be within specifications, refer to the specification chart in the appropriate engine article.
- If the pressure is not within specification, check the following possible sources: Insufficient oil Oil leakage Worn or damaged oil pump Oil pump screen cover and tube Excessive main bearing clearance Excessive connecting rod bearing clearance Chain tensioner leak
Inspection
- NOTE: New exhaust manifold gaskets, studs, nuts and/or bolts must be installed when an exhaust manifold is serviced. NOTE: Use a Straightedge that is calibrated by the manufacturer to be flat within 0.005 mm (0.0002 in) per running foot of length, such as Snap-On® GA438A or equivalent. For example, if the Straightedge is 61 cm (24 in) long, the machined edge must be flat within 0.010 mm (0.0004 in) from end to end. Using the Straightedge and a Feeler Gauge Set, check the exhaust manifold sealing surface for warpage. If the warpage is greater than 0.76 mm (0.0299 in), install a new exhaust manifold. Use the General Equipment: Feeler Gauge
- NOTE: Do not use a caustic cleaning solution or a wire brush to clean the pistons or damage can occur. Clean and inspect the (1) ring lands, (2) pin bosses, (3) skirts and the (4) tops of the pistons. If wear marks, scores or glazing is found on the piston skirt, check for a bent or twisted connecting rod.
- NOTE: Make sure the oil ring holes are clean. Using a Piston Ring Groove Scraper, clean the piston ring grooves.