Contents: Symptoms - Engine Controls ↧ Symptom Description ↧ Symptom Definition ↧ Confirmation of symptom ↧ Check symptoms ↧ Additional symptom checks ↧ The crankshaft turns but the engine… ↧ Fuel Pump Electrical Circuit… ↧ Fuel system diagnostics ↧ Checking the fuel injector coil ↧ Checking the balance of injectors ↧ Checking the fuel tank for leaks ↧ Diagnostics of the intake manifold… ↧ Diagnostics of the electronic… ↧
Symptoms - Engine Controls
Symptom Description
Symptoms of poor drivability do not cause a DTC to be set. Symptoms of poor drivability are described below. Some problems may cause several symptoms to appear at the same time. These problems are listed together. Other problems that may only cause certain symptoms are listed separately. Before starting additional symptom checks, perform the symptom checks.
Symptom Definition
Backfire:
Fuel ignites in the intake manifold or exhaust system, producing popping sounds.
Engine misfires; Delays, failures:
A constant pulsation or jerking noise that follows engine speed, usually more pronounced as engine load increases. This condition is usually not noticeable above 1500 rpm or 48 km/h (30 mph). The exhaust has a persistent snorting sound at idle or low speeds.
Detonation/knock when sparking:
A metallic knocking sound that ranges from mild to very loud, usually increasing with acceleration. The engine makes sharp metallic sounds that change as the throttle is opened.
Continuing to run the engine after the ignition is turned off; Compression ignition:
Fuel ignites in the intake manifold or exhaust system, producing popping sounds.
Difficult start:
The engine turns over normally with the starter, but does not start for a long time. The car eventually starts or may start but immediately stalls.
Delays, dips, jerks:
Lack of immediate response when pressing the accelerator pedal. This condition can be observed at any vehicle speed. Typically, this malfunction is most pronounced when attempting to move off for the first time, for example from a parking lot. This condition can cause the engine to stall under severe conditions.
Lack of power and responsiveness, soft pedal effect:
Engine produces less power than expected. Little or no increase in speed when accelerator pedal is partially depressed.
High fuel consumption:
Fuel economy measured during sea trials is significantly lower than expected. In addition, fuel economy is significantly lower than previously shown during previous sea trials.
Poor fuel filling:
difficulties when refueling the car.
Rough, erratic or improper idle and stalling:
The engine idles rough. In severe cases, the engine or vehicle may shake. The engine idle speed may vary. Any condition may be severe enough to cause the engine to stall.
Pops/shots in the silencer:
Change in engine power with constant throttle or cruise control position. The car speeds up and down without changing the gas pedal position.
Confirmation of symptom
Before using this diagnostic procedure, perform the Diagnostic System Check. Make sure all of the following conditions are met:
- The ECM and Malfunction Indicator Lamp are functioning properly.
- No DTCs recorded.
- Scan tool data is within normal operating range.
- There is no fact sheet available for this symptom.
- The ECM grounds are clean, tight, and properly connected.
- The vehicle's tires are properly inflated and meet the vehicle manufacturer's specifications.
- The air filter element is not clogged.
Check symptoms
1. Check the following:
- Fuel system for the following: Correct fuel pressure - See Fuel System Diagnosis.
- 2. Correct fuel pressure.
- 3. Leaking or malfunctioning injectors.
- 4. Contaminated or poor quality fuel.
- Ignition system for the following:
- 5. Spark plugs in incorrect temperature range or malfunctioning.
- 6. To diagnose spark plug contamination with coolant or oil.
- 7. Wet the secondary ignition system with water from a spray bottle. Wetting the secondary ignition system can help detect damaged or degraded components. While wetting the circuits, listen and look for sparking and misfires.
- 8. Weak spark.
- Transmission Torque Converter Clutch Operation - The scan tool should show a drop in engine speed when the torque converter clutch is engaged.
- Operation of the air conditioning compressor
- Conditions that may cause the engine to run lean or rich - See DTC P2178, P2180, P2188, P2190.
- Crankshaft position sensor for correct resistance - After exposure to elevated temperatures, the resistance of the crankshaft sensor may be outside the acceptable range. The resistance should be within 700-1200 Ohms.
- Engine for the following mechanical faults
- 9. Excess oil in the combustion chamber or leaking valve stem seals
- 10. Incorrect compression in cylinders
- 11. Sticking or leaking valves
- 12. Worn camshaft lobes
- 13. Incorrect valve timing
- 14. Broken valve springs
- 15. Excessive carbon deposits in combustion chambers - clean combustion chambers with a high-quality engine cleaner. Follow the instructions on the package.
- 16. Incorrect engine parts
- Vacuum hoses for cracks and fractures
- Knock Sensor System for Excessively Active Spark Retard - See Knock Sensor System Description and DTCs P0327, P0328, P0332, P0333.
- Exhaust system components as follows:
- 17. Physical damage or possible internal malfunctions
- 18. Triple-Action Catalytic Converters with Limited Flow Rate
- Electromagnetic interference in the reference circuit can cause ignition interruptions. Electromagnetic interference can usually be detected using a scanning device by monitoring the engine speed parameter. An unexpected increase in the engine speed parameter without a noticeable change in the actual engine speed indicates the presence of electromagnetic interference. Inspect high-voltage components near the ignition control circuit for problems.
- Inspect the positive crankcase ventilation system and all connections for leaks or restrictions.
- Evaporative Emission Canister Purge Solenoid Valve Stuck Open
- Engine cooling system for the following:
- 19. Correctness of thermostat temperature range.
- 20. Correct engine coolant level.
- 21. If the above conditions do not explain the symptom, proceed to additional symptom testing.
Additional symptom checks
Detonation/knock when sparking:
Check the engine for overheating.
High fuel consumption:
Check for foreign material deposits in the throttle bore and carbon deposits on the throttle plate and shaft. Also check the integrity of the throttle body.
Rough, erratic or improper idle and stalling:
Check engine mounts.
Pops/shots in the silencer:
Check the heated oxygen sensors (HO2S). The HO2S should respond quickly to changes in throttle position. If the HO2S does not respond to changes in throttle position, check for contamination from fuel, silicone, or improper use of cold-cure sealant. The sensors may have a white powdery coating that causes a false high signal, simulating a rich exhaust condition. The ECM reduces fuel delivery to the engine, causing poor drivability.
Difficult start:
- Check the engine coolant temperature sensor (EST). Compare the engine coolant temperature sensor reading with the intake air temperature sensor reading on a cold engine. The engine coolant sensor and the intake air temperature sensor must not differ by more than±3°C (5°F). If the engine coolant sensor diverges from the intake air temperature sensor by more than the specified amount, check the resistance of the engine coolant sensor. For resistance characteristics, see Resistance versus Temperature-Engine Coolant Temperature Sensor. If the resistance is outside the rated range, replace the engine coolant temperature sensor. If the sensor resistance meets the specifications, check the engine coolant temperature sensor circuits for high resistance.
- Check the operation of the fuel pump relay. The fuel pump should turn on for 2 seconds when the ignition is turned on.
Delays, dips, jerks:
- Check the pressure in the fuel system.
- Check the generator.
High fuel consumption:
- Heavy loads in a vehicle or on a trailer
- Too much or too frequent acceleration
- Check for foreign material deposits in the throttle bore and carbon deposits on the throttle plate and shaft. Also check the integrity of the throttle body.
The crankshaft turns but the engine does not start
Diagnostic information about the malfunction
Description of circuits/systems
The "Crankshaft Cranks But Engine Won't Start" diagnostic is a systematic method to determine the problem that is causing this condition. This diagnostic directs the technician to the appropriate diagnostic procedure for the system.
Diagnostic information
Check for the following conditions:
- The ECM uses signals from the camshaft position sensors to determine the engine speed and the position at which the crankshaft position sensor malfunction is observed.
- The engine will only operate with a faulty CKP sensor if the ECM controller has stored the previously defined camshaft reference positions in memory. If there is a problem in the signal circuit of the crankshaft position sensor, the engine goes into emergency mode (Limp Home) after a hard restart. In this mode, the ECM controller calculates engine speed from one of the camshaft position sensors. The following DTCs can be set in limp home mode and should be ignored:
- DTC P0324 Knock Sensor Module Performance
- DTC P1011 Intake Camshaft Position Actuator Home Position Bank 1
- Failure to start may be caused by insufficient fuel. Carefully inspect the fuel delivery system to ensure that there is sufficient fuel being delivered to the fuel injectors. Inspect the fuel delivery system components for partial blockages or restrictions. If there is insufficient fuel, the engine may not start. Carefully inspect the fuel delivery system to ensure that there is sufficient fuel being delivered to the fuel injectors. Inspect the fuel delivery components for blockages or restrictions.
- Fuel injectors with partially clogged or restricted nozzles or a faulty solenoid may cause a no-start condition.
- The fuel injectors may be injecting fuel and the indicated fuel pressure may be accurate, but there may not be enough fuel to start the engine. The fuel injectors and injector circuit are OK, fuel injection is detected, but the fuel injector on time may be inappropriate. If the ECM is receiving inaccurate input signals from the various reporting sensors, the fuel injectors may not be delivering the proper amount of fuel to start the engine. Check all engine data parameters with a scan tool and compare the values shown to expected values or values from a vehicle known to be in good condition.
- Check the engine status control signal from the crankshaft position sensor with a scanning device. Monitor the engine speed parameter while cranking the crankshaft. When cranking the crankshaft, the scanning device should steadily show 200-300 rpm. If the values are inaccurate, for example, if sharp jumpy signals are detected reflecting the engine speed, the engine status control signal is not stable enough, which is why the engine cannot start and run properly.
- Check the reliability and serviceability of the electrical grounding points of the engine.
- If the engine almost starts and then stalls, check the ground circuit of the crankshaft position sensor and camshaft position sensor for an open.
- Water or foreign matter in the fuel may cause the engine to fail to start or run erratically. In freezing weather, the coolant may freeze in the fuel system. In a heated workshop, the engine may start after 30 minutes. The problem may not reoccur until the vehicle is left overnight in freezing temperatures. Extremely adverse weather conditions may cause fuel contamination to prevent the engine from starting.
- If the vehicle starts and runs after being taken to a shop because it cannot start, the ignition system has been exposed to moisture. Water should be sprayed on the ignition components and wires to test for starting or if the engine is running erratically.
An intermittent fault may be caused by a fault in one of the electrical data circuits or components. Check for intermittent faults in the wiring harness or individual components.
Checking circuits/systems
1. Try to start the engine. The engine should start and idle.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.
Circuit/System Testing
1. Ignition ON, retrieve DTC information with a scan tool. Verify that DTCs P0685, P0686, P0687, P0689, or P0690 are not set.
- If any of these DTCs are set, proceed to further diagnostics for DTC P0685, P0686, P0687, P0689, or P0690.
2. Crank the engine for 15 seconds. Observe the DTC information with a scan tool. Verify that DTCs P0116, P0118, P0119, P0201-P0206, P0335, P0336, P0337, P0338, P0351-P0356, P0601, P0602, P0604, P0606, P0627, P0628, P0629, P1629, P1630, P1631, or P2105 are not set.
- If any of the listed diagnostic trouble codes are set, refer to the information for that DTC.
3. Turn on ignition, check the anti-theft system parameter using a scanning device. The parameter value should be Disabled.
- If Enabled is displayed, refer to the information for the corresponding DTC.
4. Turn on the ignition, use the scanning device to give the command to turn on the fuel pump. The sound of the fuel pump turning on should be heard.
- If the fuel pump does not turn on, see Fuel Pump Electrical Circuit Diagnosis.
5. Turn off the ignition, install the fuel pressure gauge.
Important:
- It may take several cycles of the fuel pump to achieve maximum fuel pressure.
- DO NOT start the engine during this check.
6. Turn on the ignition, use a scanning device to command the fuel pump to turn on. The fuel pressure should be within 380-410 kPa (55-60 psi).
- If the fuel pressure is not within the specified range, see Fuel System Diagnosis.
7. Check for the following problems:
- Disconnect the MAF sensor. The ECM will ignore the MAF sensor and use the calculated flow.
- If disconnecting the MAF sensor resolves the problem and the connections are OK, replace the MAF sensor.
- Pinched air intake pipe to throttle body.
- The air filter capacity has been reduced.
- Spark plugs contaminated with fuel or coolant.
- Inaccurate Manifold Absolute Pressure (MAP) Sensor
- Inaccurate Engine Coolant Temperature (ECT) Sensor
- Obstruction in the exhaust system
- Fuel contamination
- Mechanical engine problems, such as worn timing chain and gears, low compression.
- If any of the above faults are detected, they should be corrected.
Fuel Pump Electrical Circuit Diagnostics
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Description of circuits/systems
The ECM supplies ground to the fuel pump relay coil. When the ignition is first turned on, the ECM turns on the fuel pump relay, which supplies power to the fuel pump. The ECM holds the fuel pump relay on as long as the engine is cranking or running and crankshaft reference pulses are being received. If crankshaft reference pulses are not received, the ECM turns off the fuel pump after approximately 3 seconds.
Diagnostic information
A blown fuel pump fuse may be caused by the following reasons:
- Fuse failure.
- Intermittent short circuit to ground in the fuel pump voltage supply circuit.
- Intermittent internal fuel pump failure.
Checking circuits/systems
Important: When using the fuel pump control output, fuel pump DTCs may be set.
1. Turn on the ignition, use a scanning device to command the fuel pump relay to turn on. You should hear the fuel pump turn on for 3-5 seconds and then turn off.
2. If the vehicle passes the circuit/system check, the diagnostic conditions should be met. The conditions recorded in the Failure Records/Status Records data may also be met.
Circuit/System Testing
1. Turn off the ignition, the fuel pump should not work.
- If the fuel pump runs without shutting off, check the fuel pump supply voltage circuit for a short to power. If the circuit/connection check does not reveal any faults, replace the fuel pump relay.
2. Check the fuel pump fuse. The fuse should not be open.
- If the fuel pump fuse is open, check the fuel pump supply voltage circuit for a short to ground. If the circuit and connections are normal, replace the fuel pump.
3. Turn off the ignition, remove the fuel pump relay from the electrical unit.
4. Turn ignition on, check battery voltage between B+ circuit of fuel pump relay and ground.
- If voltage is less than B+, repair open/high resistance in fuel pump relay B+ voltage circuit.
5. Install a jumper wire with a 15 amp fuse between the B+ circuit of the fuel pump relay and the fuel pump supply voltage circuit. The fuel pump should turn on.
- If the fuel pump does not work, check for the following conditions:
- Open/high resistance in fuel pump supply voltage circuit
- Open/High Resistance in Fuel Pump Ground Circuit
- If the specified circuit and connections are normal, replace the fuel pump.
6. If checking all circuits/connections reveals no fault, check or replace the fuel pump relay.
Component testing
1. Measure the resistance between terminals 85 and 86 of the fuel pump relay; the resistance should be within 70 - 110 Ohms.
- If the resistance is not within the specified range, replace the fuel pump relay.
2. Measure the resistance between the following terminals of the fuel pump relay; the resistance must be infinite:
- 30 and 86
- 30 and 87
- 30 and 85
- 85 and 87
- If a connection is found, replace the fuel pump relay.
3. Connect a jumper wire with a 20 A fuse between the positive battery terminal and terminal 85 of the fuel pump relay. Connect a jumper wire between the negative battery terminal and terminal 86 of the fuel pump relay. Measure the resistance between terminals 30 and 87 of the fuel pump relay; the resistance should be less than 2 ohms.
- If the resistance is greater than 2 ohms, replace the fuel pump relay.
Fuel system diagnostics
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Description of circuits/systems
The control module turns on the fuel pump relay when the ignition is turned on. If the control module does not detect ignition reference pulses, it turns off the fuel pump relay after 2 seconds. The control module maintains the fuel pump relay in the on state as long as ignition reference pulses are received. The control module turns off the fuel pump relay after 2 seconds if ignition reference pulses are no longer received and the ignition remains on.
The fuel system is a returnless, on-demand design. The fuel pressure regulator is part of the primary fuel tank module, eliminating the need for a return fuel line from the engine. The returnless fuel system reduces the temperature inside the fuel tank by preventing hot fuel from returning from the engine to the fuel tank. Reducing the temperature in the fuel tank reduces the emission of fuel vapor.
An electric turbine fuel pump is attached to the primary fuel tank module inside the fuel tank. The fuel pump delivers fuel under high pressure through the fuel filter, through the fuel pressure regulator and the fuel supply line to the fuel injection system. The fuel pressure regulator has a tee that diverts the required portion of the fuel to the fuel rail, while unused fuel returns to the primary fuel tank module reservoir. The primary fuel tank module has a return flow check valve. The check valve and fuel pressure regulator maintain fuel pressure in the fuel supply line and fuel rail to reduce engine starting time.
The primary fuel tank module also includes a primary jet pump and a secondary jet pump. Excess fuel from the fuel pump, caused by the expulsion of vapors from the pump inlet chamber, is diverted to the primary jet pump and the secondary jet pump through a restriction diaphragm located in the pump cover. The primary jet pump fills the primary fuel tank module reservoir. The secondary jet pump, using the Venturi effect, draws fuel from the secondary compartment of the fuel tank through the fuel transfer tube into the primary compartment of the fuel tank.
Diagnostic information
- If the fuel runs out before the fuel level indicator reaches zero, this may indicate a malfunction of the siphon jet pump or the connecting lines between the fuel tanks. Inspect for blockages, foreign objects, or capacity limitations in all relevant components.
- If the fuel runs out before the fuel gauge reaches zero, it may be due to a faulty fuel gauge. Check the float arm for binding or obstruction.
Checking circuits/systems
Important:
- Before proceeding further, inspect the fuel system for damage and external leaks.
- Before proceeding further, make sure there is enough fuel in the fuel tank.
- It may take several cycles of the fuel pump relay to achieve maximum fuel pressure.
- DO NOT start the engine.
1. Turn on the ignition, use a scanning device to command the fuel pump relay to turn on. You should hear the fuel pump turn on for 3-5 seconds and then turn off.
- If the fuel pump does not turn on, see Fuel Pump Electrical Circuit Diagnosis.
2. Turn off the ignition, turn off all additional equipment, install the fuel pressure gauge.
3. Turn ignition on, use scan tool to command fuel pump relay to turn on. Check that fuel pressure is between 380-410 kPa (55-60 psi) and remains stable for 5 minutes.
4. Test the vehicle under the conditions that caused the customer's problems, monitoring the fuel system parameters with a scan tool.
- If the scan tool parameters do not indicate a lean condition, see Symptoms - Engine Controls.
Circuit/System Testing
1. Turn on the ignition, command the fuel pump relay to turn on and monitor the fuel pressure while the fuel pump is running. Make sure the fuel pressure is between 380-410 kPa (55-60 psi).
- If the fuel pressure is above the specified range, replace the fuel pump.
- If the fuel pressure is below the specified range, remove the fuel tank and check/inspect for the following:
- Limitation of the cross-section of the fuel supply line
- Clogged or clogged fuel filter
- Clogged or clogged mesh filter
- Fuel level float stuck or catching on obstructions
- Clogged jet siphon pump
- Clogged transfer lines between fuel tanks
- Faulty fuel pressure regulator
- Poor connections in wiring harness connectors and fuel pump ground circuits
- If any faults are detected, take measures to eliminate them.
- If all components are normal, replace the fuel pump.
Important: When the fuel pump is turned off, the fuel pressure may change slightly. After the fuel pump stops, the fuel pressure should stabilize and remain constant.
2. Make sure the fuel pressure does not decrease faster than 34 kPa (5 psi) in 1 minute.
- If the fuel pressure decreases faster than the specified value, perform the following procedure:
- Turn off the ignition, relieve the fuel pressure.
- Install the fuel pressure gauge.
- Make sure the fuel pressure does not decrease faster than 34 kPa (5 psi) in 1 minute.
- If the fuel pressure remains constant, replace the fuel pump.
- If the fuel pressure drops, find and replace the leaking fuel injector.
3. Relieve fuel pressure to 69 kPa (10 psi). Make sure that fuel pressure does not drop more than 14 kPa (2 psi) in 5 minutes.
- If fuel pressure drops faster than specified, replace the fuel pump.
4. Remove the fuel pressure gauge.
5. Test the vehicle under the conditions that caused the customer's problems, monitoring the fuel system parameters with a scan tool.
- If the scan tool parameters indicate a lean mixture, check/inspect for the following:
- Limitation of the cross-section of the fuel supply line
- Clogged fuel filter
- Clogged jet siphon pump
- Clogged transfer lines between fuel tanks
- Faulty fuel pressure regulator
- Poor connections in wiring harness connectors and fuel pump ground circuits
- If no fault is found when checking all components, and the scanning device indicates the presence of a lean fuel mixture, then replace the fuel pump.
Checking the fuel injector coil
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Description of circuits/systems
The control module supplies the appropriate pulses to turn on the injectors for all cylinders. The ignition voltage is supplied directly to the fuel injectors. The control module controls the operation of each fuel injector by grounding the control circuit through a built-in semiconductor key - former. Increased or decreased resistance of the fuel injector coil winding worsens engine performance. A diagnostic trouble code for the fuel injector control circuit may not be set, but misfire is possible. Temperature also affects the ignition coil winding. The resistance of the fuel injector coil windings increases with increasing fuel injector temperature.
Diagnostic information
- To determine which injector is causing this condition, it is helpful to refer to the misfire meters or chart.
- If the vehicle is operated in wide temperature ranges, this will help to identify the fuel injector causing the deviation.
- Perform a fuel injector coil test under the conditions that the customer experienced the problem. Fuel injector malfunction may occur at certain temperatures or under certain conditions.
Component testing
Check the resistance of all fuel injector coils using one of the following methods:
- If the engine coolant temperature sensor reading is between 10-32°C (50-90°F), the resistance of each fuel injector coil should be 11-14 ohms.
- If the resistance of the coil of any injector is not within 11-14 Ohms, replace that injector.
- If the engine coolant temperature sensor reading is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector coil with a digital multimeter. Subtract the lowest resistance from the highest resistance. The difference between the highest and lowest resistances should not exceed 3 ohms.
- If the difference does not exceed 3 Ohms, see further diagnostics in the section "Checking the injector balance".
- If the difference is greater than 3 ohms, sum all the fuel injector coil resistances to obtain the total resistance value. Divide the total resistance value by the number of fuel injectors to obtain the average resistance value. Subtract the lowest and highest resistance values from the average resistance value. Replace the fuel injector that has the greatest difference in resistance when it exceeds or falls below the average value.
Checking the balance of injectors
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Example of checking the balance of injectors
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Cylinder
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1
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2
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3
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4
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5
|
6
|
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First meaning
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360 kPa (52 psi)
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360 kPa (52 psi)
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360 kPa (52 psi)
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360 kPa (52 psi)
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360 kPa (52 psi)
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360 kPa (52 psi)
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|
Second meaning
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195 kPa (28 psi)
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138 kPa (20 psi)
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195 kPa (28 psi)
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195 kPa (28 psi)
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235 kPa (34 psi)
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195 kPa (28 psi)
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Fall
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166 kPa (24 psi)
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222 kPa (32 psi)
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166 kPa (24 psi)
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166 kPa (24 psi)
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125 kPa (18 psi)
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166 kPa (24 psi)
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Average range: 156..176 kPa (22.5...25.5 psi)
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The injector is normal
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Fuel Injector - Pressure Drop Too High
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The injector is normal
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The injector is normal
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Faulty injector - too little pressure drop
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The injector is normal
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Description of circuits/systems
First, a scan tool is used to apply current to the fuel pump relay coil. Then, using a tester, each fuel injector is turned on for a certain amount of time to deliver a measured amount of fuel to the intake manifold. This causes a pressure drop in the system, which can be recorded and used to compare injectors.
Diagnostic information
- To determine which injector is causing this condition, it is helpful to refer to the misfire meters or chart.
- If the vehicle is operated in wide temperature ranges, this will help to identify the fuel injector causing the deviation.
- Perform a fuel injector balance test under the conditions in which the customer experienced the problem. Fuel injector malfunction may occur at certain temperatures or under certain conditions.
Component testing
Checking the balance of injectors
1. Turn ignition on, use scan tool to verify engine coolant temperature is below 94°C (201°F).
- If the engine coolant temperature is greater than 94°C (201°F), allow the engine to cool before proceeding.
2. Turn off the ignition, install the fuel pressure gauge.
3. Turn on the ignition, make sure that the fuel pressure is within 380-410 kPa (55-60 psi).
- If the fuel pressure is not within the specified range, perform further diagnostics of the fuel system according to the section "Diagnostics of the fuel system".
4. Monitor the fuel pressure gauge for 1 minute. Make sure the fuel pressure has dropped no more than 34 kPa (5 psi).
- If the fuel pressure drops more than 34 kPa (5 psi), perform further fuel system diagnostics according to the Fuel System Diagnostics section.
Note: To avoid flooding the engine, DO NOT REPEAT any part of this test without first running the engine.
5. Connect the fuel injector tester to the fuel injector, setting the current switch on the fuel injector tester to the Balance Test 0.5-2.5 A position.
6. Using a scanning device, give a command to turn on the fuel pump relay and after the fuel pressure has stabilized, record the fuel pressure on the fuel pressure gauge. This will be the first pressure reading.
Important:
- Repeat this step for each fuel injector to obtain the pressure drop value for each fuel injector.
- Fuel pressure may increase after the fuel injector pulsing has ended. Record the fuel pressure reading immediately after the fuel injector pulsing has ended. DO NOT record the increased fuel pressure.
7. Apply power to the fuel injector by pressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure on the fuel pressure gauge after the end of the pulse supply to the fuel injector. This will be the second pressure reading.
8. Add up all the pressure drop values; this will give you the total pressure drop. Divide the total drop by the number of fuel injectors to get the average pressure. The difference between the pressure drop for each individual injector and the average pressure drop should not be more than 20 kPa (3 psi).
- If the difference between the pressure drop for any injector and the average pressure drop is greater than 20 kPa (3 psi), replace the fuel injector.
Checking the fuel tank for leaks
Caution! Before checking the fuel tank for leaks, place a dry chemical fire extinguisher (Class B) nearby. Before removing the fuel tank suspected of leaking, make sure that no fuel is leaking from the fuel lines or fuel pipes onto the tank. After removing the tank, make sure that no fuel is leaking around the O-ring of the fuel level sensor. Failure to do so may result in an accident.
Diagnostic information about the malfunction
Before using this diagnostic procedure, it is essential to perform a diagnostic system check.
Description of circuits/systems
Checking the fuel tank for leaks allows you to detect a leak of fuel or fuel vapors from the fuel tank. Fuel vapor leaks above the fuel level will be detected at the end of one diagnostic cycle of the fuel vapor capture system. The fault indicator lamp lights up after 2 diagnostic cycles of the fuel vapor capture system, if the leak is large, or up to 8 diagnostic cycles of the fuel vapor capture system, if the leak is small, only if there is a fault.
Diagnostic information
- Operate the vehicle under the conditions in which the user experienced the malfunction. At high temperatures, the amount of fuel vapor may increase so much that the fuel vapor in the adsorber reaches saturation. In this case, the fuel vapor will be released into the atmosphere. After starting the engine and activating the purge of the fuel vapor recovery system, the release of fuel vapor into the atmosphere will stop.
- If the problem is intermittent, wiggling the evaporative emission system tubes and fuel lines may help.
- When the fuel level is low, a liquid fuel leak may not be apparent.
Checking circuits/systems
1. Make sure the fuel tank and fuel lines are not damaged or leaking.
- If any faults are detected, take measures to eliminate them.
2. Turn on ignition, use scan tool to command fuel pump relay to turn on. Make sure fuel lines are not leaking.
- If any faults are detected, take measures to eliminate them.
Important: For detailed instructions, refer to the J 41413-200 Evaporative Emission Tester Operating Manual.
3. Turn off ignition, connect J 41413-200 and GE-41415-50 to fuel filler neck.
4. Using a scanning device, send a command to close the ventilation valve of the fire safety system.
5. Set the nitrogen/smoke supply valve to the nitrogen supply position and ensure that there is no fluid leakage from the pressurized system.
- If a leak is detected, take steps to eliminate it.
Important: It may be necessary to partially lower the fuel tank.
6. Using J 41413-200, inject smoke into the fuel vapor recovery system. Verify that there are no vapor leaks at the following locations:
- Fuel tank, fill limiting vent valve, relief valve, step vent valve
- Fuel level sensor housing, fuel level sensor seal, fuel line, fuel vapor recovery system tubes
- Fuel tank pressure sensor seal
- Fuel filler neck and hose
- If a leak is noticed, take steps to eliminate it.
Component testing
Checking the balance of injectors
1. Turn ignition on, use scan tool to verify engine coolant temperature is below 94°C (201°F).
- If the engine coolant temperature is greater than 94°C (201°F), allow the engine to cool before proceeding.
2. Turn off the ignition, install the fuel pressure gauge.
3. Turn on the ignition, make sure that the fuel pressure is within 380-410 kPa (55-60 psi).
- If the fuel pressure is not within the specified range, perform further diagnostics of the fuel system according to the section "Diagnostics of the fuel system".
4. Monitor the fuel pressure gauge for 1 minute. Make sure the fuel pressure has dropped no more than 34 kPa (5 psi).
- If the fuel pressure drops more than 34 kPa (5 psi), perform further fuel system diagnostics according to the Fuel System Diagnostics section.
Note: To avoid flooding the engine, DO NOT REPEAT any part of this test without first running the engine.
5. Connect the fuel injector tester to the fuel injector, setting the current switch on the fuel injector tester to the Balance Test 0.5-2.5 A position.
6. Using a scanning device, give a command to turn on the fuel pump relay and after the fuel pressure has stabilized, record the fuel pressure on the fuel pressure gauge. This will be the first pressure reading.
Important:
- Repeat this step for each fuel injector to obtain the pressure drop value for each fuel injector.
- Fuel pressure may increase after the fuel injector pulsing has ended. Record the fuel pressure reading immediately after the fuel injector pulsing has ended. DO NOT record the increased fuel pressure.
7. Apply power to the fuel injector by pressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure on the fuel pressure gauge after the end of the pulse supply to the fuel injector. This will be the second pressure reading.
8. Add up all the pressure drop values; this will give you the total pressure drop. Divide the total drop by the number of fuel injectors to get the average pressure. The difference between the pressure drop for each individual injector and the average pressure drop should not be more than 20 kPa (3 psi).
- If the difference between the pressure drop for any injector and the average pressure drop is greater than 20 kPa (3 psi), replace the fuel injector.
Diagnostics of the intake manifold geometry change valve control system
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Description of circuits/systems
The Intake Manifold Runner Control (IMRC) valve changes the configuration of the intake manifold chamber. When the IMRC valve is open, the intake manifold is one large chamber.
When the IMRC valve is closed, the intake manifold is divided into 2 smaller chambers. The IMRC valve improves engine performance at low and high speeds.
Ignition voltage is applied directly to the IMRC solenoid. The ECM controls the valve by grounding the control circuit through a semiconductor device called a driver. The device has a feedback circuit that increases the voltage. The ECM can detect an open circuit, short to ground, or short to voltage by monitoring the feedback voltage.
Diagnostic information
Check the IMRC solenoid for signs of the valve hitting the intake manifold. This condition may be temperature dependent.
Checking circuits/systems
Ignition ON, retrieve DTC information with a scan tool. Verify that DTCs P2008, P2009, or P2010 are not set.
- If any of the listed DTCs are set, refer to the corresponding DTC information for further diagnosis.
Circuit/System Testing
1. Turn off ignition, remove IMRC valve control solenoid from intake manifold by disconnecting electrical connector.
2. Turn ignition on, command IMRC solenoid ON and OFF using scan tool. Verify IMRC solenoid operates in both directions.
- If the IMRC solenoid does not operate in both directions, replace the IMRC solenoid.
3. Inspect the inside of the intake manifold for the following:
- Carbon deposits preventing IMRC valve movement
- Flash preventing IMRC valve movement
- Foreign bodies interfering with IMRC valve movement
- If a problem is detected, take steps to eliminate it.
4. Clean or replace the upper intake manifold.
Diagnostics of the electronic ignition system
Diagnostic information about the malfunction
Before using this diagnostic procedure, you should perform a diagnostic system check.
Description of circuits/systems
Ignition voltage 1 is applied to the ignition coils. The ECM supplies ground to the ignition coil control circuits. When the ECM opens the ground of the primary ignition coil, the magnetic field of the coil disappears. The disappearance of the magnetic field causes high voltage to appear on the secondary winding, which creates a discharge on the spark plugs. The ignition sequence and timing are controlled by the ECM.
Diagnostic information
- The ignition coils of each cylinder bank have independent fuses. If the fuse opens or the ignition voltage circuit 1 is broken between the fuse and the cable junction, all ignition coils of the engine cylinder bank stop working. If the ground circuit is broken at the engine cylinder block, the ignition coils on one engine cylinder bank stop working.
- Inspect the ignition coils to see if any aftermarket devices were installed. Connecting any foreign devices to the ignition coil circuits can cause ignition coil malfunctions.
Circuit/System Testing
Important: This diagnostic procedure is performed only if you came here with a diagnostic trouble code related to misfiring or from the "Crankshaft turns but the engine does not start" diagnostic.
1. Turn off the ignition, disconnect the harness connector from the ignition coil.
2. Turn on the ignition, check the battery voltage under load between the ignition coil 1 ignition voltage circuit and ground.
- If voltage is below B+, repair short to ground or open/high resistance in ignition coil 1 voltage circuit.
3. Turn off ignition, check resistance between ignition coil ground circuit and negative battery terminal; the resistance should be below 5 ohms.
- If resistance is greater than 5 ohms, repair open/high resistance in ignition coil ground circuit.
4. If no fault is found when testing all circuits/connections, replace the ignition coil.
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