Symptoms - Engine Controls
Description of the symptom
The drivability symptoms do not trigger a DTC. The symptoms of poor drivability are described below. Some problems can cause multiple symptoms to appear at the same time. These problems are listed together. Other problems that may cause only certain symptoms are listed separately. Before starting additional symptom checks, perform symptom checks.
Symptom Definition
Backfire:
The fuel ignites in the intake manifold or in the exhaust system, producing pops.
Interruptions in the engine; Delays, failures:
A constant pulsing or jerking following the speed of the motor, usually more pronounced as the load on the motor increases. This condition is usually not felt above 1500 rpm or 48 km/h (30 mph). The exhaust has a persistent snorting sound at idle or low rpm.
Detonation / detonation during sparking:
Mild to very severe metallic knocking, usually worse with acceleration. The engine makes sharp metallic sounds that change with the opening of the throttle.
Continuation of engine operation after turning off the ignition; Self-ignition by compression:
The fuel ignites in the intake manifold or in the exhaust system, producing pops.
Difficult start:
The engine turns normally with the starter, but does not start for a long time. The vehicle eventually starts or may start but stall immediately.
Delays, dips, jerks:
Lack of instant response when pressing the accelerator pedal. This condition can be observed at any vehicle speed. Typically, this problem is most pronounced when you try to start off for the first time, for example, from a parking lot. This condition can cause the engine to stall under severe conditions.
Insufficient power and throttle response, soft pedal effect:
The engine develops less power than expected. Little or no increase in speed when the accelerator pedal is partially depressed.
High fuel consumption:
Fuel economy measured in sea trials is significantly lower than expected. In addition, fuel economy is noticeably less than previously shown in previous sea trials.
Poor filling with fuel:
difficulties when refueling the car.
Rough, erratic or incorrect idling and shutdown:
The engine runs rough at idle. In severe cases, the engine or vehicle may shake. Engine idle speed may vary. Any condition can be serious enough to cause the engine to shut down.
Pops / shots in the silencer:
Variation in engine power at constant throttle or cruise control. There is a set and a decrease in speed by the car without changing the position of the gas pedal.
Symptom confirmation
Perform a Diagnostic System Check before using this diagnostic procedure. Make sure all of the following conditions are met:
- The ECM and MIL are working properly.
- No DTCs recorded.
- The scan tool data is within the normal operating range.
- There is no fact sheet for this symptom.
- The ECM grounds are clean, tight, and properly connected.
- The vehicle's tires are properly inflated and meet the specifications of the vehicle manufacturer.
- The air filter element is not clogged.
Checking for symptoms
1. Check the following:
- Fuel system for the following: Correct fuel pressure - Refer to 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 at wrong temperature range or malfunction.
- 6. For diagnosing contamination of spark plugs with coolant or oil.
- 7. Moisten the secondary ignition system with spray water. Humidifying the secondary ignition system can help detect damaged or degraded components. When moistening the circuits, visually and aurally monitor sparks and misfires.
- 8. Weak spark.
- Transmission Torque Converter Clutch Operation - The scan tool should show a drop in engine RPM when the torque converter clutch is engaged.
- Air conditioning compressor operation
- Causes that can 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 out of range. The resistance should be in the range of 700-1200 ohms.
- Engine for the following mechanical problems
- 9. Too much oil in the combustion chamber or leaking valve stem seals
- 10. Incorrect compression in the cylinders
- 11. Sticky or Leaking Valves
- 12. Worn camshaft lobes
- 13. Incorrect valve timing
- 14. Broken valve springs
- 15. Excessive soot deposits in combustion chambers - Clean combustion chambers with a high quality engine cleaner. Follow the instructions on the package.
- 16. Wrong engine parts
- Vacuum hoses for cracks and fractures
- Knock sensor system for excessively active spark delay - Refer to Knock Sensor System Description and DTCs P0327, P0328, P0332, P0333.
- Exhaust system components for the following:
- 17. Physical damage or possible internal problems
- 18. Triple-acting catalytic converters for limited capacity
- EMI in the reference circuit can cause misfiring. EMI can usually be detected with a scan tool by monitoring the RPM parameter of the engine. 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 flow restrictions.
- Stuck open evaporative emission canister purge solenoid valve
- Engine cooling system for the following:
- 19. The correct temperature range of the thermostat.
- 20. Correct engine coolant level.
- 21. If the conditions listed above do not explain the symptom, proceed to additional symptom checks.
Additional symptom checks
Detonation / detonation during sparking:
Check engine for overheating.
High fuel consumption:
Check for deposits of foreign material in the throttle bore and carbon deposits on the plate and throttle shaft. Also check the integrity of the throttle body.
Rough, erratic or incorrect idling and shutdown:
Check engine mounts.
Pops / shots in the silencer:
Check 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 misuse of cold sealant. There may be a white, powdery coating on the sensors, resulting in a false high signal, simulating rich exhaust. The ECM reduces the fuel supply to the engine, causing poor drivability.
Difficult start:
- Check Engine Coolant Temperature Sensor (EATING). Compare the reading of the engine coolant temperature sensor with the reading of the intake air temperature sensor with a cold engine. The readings of the engine coolant sensor and the intake air temperature sensor must differ by no more than±3°C (5°F). If the engine coolant sensor differs from the intake air temperature sensor by more than the specified amount, check the resistance of the engine coolant sensor. For resistance specifications, see Resistance vs. Temperature - Engine Coolant Temperature Sensor. If the resistance is out of specification, replace the engine coolant temperature sensor. If the sensor resistance is within specification, test 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 generator.
High fuel consumption:
- Heavy loads in a car or on a trailer
- Too much or too fast acceleration
- Check for deposits of foreign material in the throttle bore and carbon deposits on the plate and throttle shaft. Also check the integrity of the throttle body.
The crankshaft turns, but the engine does not start
Fault diagnostic information
Description of circuits / systems
Diagnostics "The crankshaft turns, but the engine does not start" is a systematic technique for identifying the problem that caused this condition. This diagnostic directs the technician to the appropriate system diagnostic procedure.
Diagnostic Information
Check for the following conditions:
- The ECM uses the signals from the camshaft position sensors to determine the engine speed and the position at which the crankshaft position sensor has failed.
- The engine will only run with a bad CKP sensor if the ECM has stored the previously determined camshaft home positions. If there is a problem in the signal circuit of the crankshaft position sensor, the engine will go into emergency mode after a hard restart (Limp Home). In this mode, the ECM calculates engine RPM from one of the camshaft position sensors. The following DTCs may 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
- Inability to start may be caused by insufficient fuel. Carefully check the fuel supply system to make sure there is sufficient fuel being supplied to the fuel injectors. Inspect fuel system components for partial obstruction or restricted flow. If there is not enough fuel, the engine may not start. Carefully check the fuel supply system to make sure there is sufficient fuel being supplied to the fuel injectors. Check the fuel supply components, making sure there are no blockages or obstructions.
- Fuel injectors with partially clogged or restricted nozzles or a bad solenoid can cause a start failure.
- Fuel injectors may inject fuel and 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 duration of the fuel injector in the on position may be inconsistent. If the ECM receives inaccurate inputs from various informing sensors, an inappropriate amount of fuel supplied by the fuel injectors to start the engine can be generated. Check all engine data parameters with a scan tool and compare the values shown with expected values or with a vehicle known to be in good condition.
- Check the check engine status signal from the crankshaft position sensor with a scan tool. When cranking the crankshaft, monitor the engine speed parameter. When cranking the crankshaft, the scan tool should steadily show 200-300 rpm. If the values are inaccurate, such as when sudden spikes in the engine RPM are detected, the engine status monitor signal is not stable enough, causing the engine to not start and run properly.
- Check the reliability and serviceability of the electrical ground points of the engine.
- If the engine almost starts and then stalls, test the crankshaft position sensor ground circuit and the camshaft position sensor ground circuit for an open circuit.
- Water or foreign matter in the fuel can cause the engine to not start or run erratically. In freezing weather, coolant can freeze in the fuel system. In a heated workshop, the engine can start after 30 minutes. The fault cannot recur until the vehicle is left overnight in freezing temperatures. Extremely adverse weather conditions can cause fuel contamination to prevent the engine from starting.
- If the car starts and the engine is running after being delivered to the workshop because it cannot start, then its ignition system is exposed to moisture. It is necessary to spray water on the ignition system components and wires to check the engine starts or if the engine is unstable.
An intermittent failure may be caused by a failure in any of the electrical circuits for data transmission or components. Check for intermittent faults in the wiring harness or individual components.
Circuit/System Testing
1. Try to start the engine. The engine should start and run at idle.
2. If the vehicle has successfully passed the circuit/system test, then the conditions required for diagnosis should be provided. It is also possible to provide the conditions recorded in the status/fault log data records.
Circuit / system test
1. Ignition ON, obtain DTC information with a scan tool. Verify DTCs P0685, P0686, P0687, P0689, or P0690 are not set.
- If any of these DTCs set, proceed to further diagnosis for DTC P0685, P0686, P0687, P0689, or P0690.
2. Rotate the crankshaft for 15 seconds. Check the DTC data 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, P16 29, P1630, P1631 or P2105 not installed.
- If any of the listed diagnostic trouble codes are installed, see the information on this DTC.
3. Ignition on, monitor the anti-theft parameter with a scan tool. Parameter value must be Disabled (Disabled).
- If Enabled is displayed, refer to the relevant DTC information.
4. Ignition ON, use a scan tool to command the fuel pump to turn on. You should hear the sound of the fuel pump turning on.
- If the fuel pump does not turn on, refer to Fuel Pump Electrical Circuit Diagnosis.
5. Switch off the ignition, install a fuel pressure gauge.
Important:
- It may take several cycles of the fuel pump to reach maximum fuel pressure.
- DO NOT start the engine during this test.
6. Ignition ON, use a scan tool to command the fuel pump to turn on. Fuel pressure should be within 380-410 kPa (55-60 psi).
- If fuel pressure is not within the specified range, refer to Fuel System Diagnosis.
7. Check for the following problems:
- Disconnect the mass air flow sensor. The ECM will ignore the mass air flow sensor and use the calculated flow rate.
- If disconnecting the MAF sensor corrects the problem and the connections are good, replace the MAF sensor.
- Pinched air intake pipe to throttle body.
- The capacity of the air filter has been reduced.
- Contaminated spark plugs with fuel or coolant.
- Inaccurate manifold absolute pressure sensor (MAP)
- Inaccurate engine coolant temperature sensor (EATING)
- Obstruction in the exhaust system
- Fuel contamination
- Mechanical problems with the engine, such as wear on the drive chain and timing gears, low compression.
- If any of the above faults is found, it should be eliminated.
Fuel Pump Electrical Circuit Diagnosis
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
Description of circuits / systems
The ECM applies 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 while the engine is cranking or running and the crankshaft reference pulses are on. If no crankshaft references are received, the ECM turns off the fuel pump after approximately 3 seconds.
Diagnostic Information
A blown fuel pump fuse can be caused by the following reasons:
- Fuse failure.
- Intermittent short to ground in fuel pump voltage supply circuit.
- Intermittent internal fuel pump failure.
Circuit/System Testing
Important: When using the fuel pump control output, fuel pump DTCs may be set.
1. Ignition ON, use a scan tool 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 has successfully passed the circuit/system test, then the conditions required for diagnosis should be provided. It is also possible to provide the conditions recorded in the status/fault log data records.
Circuit / system test
1. Switch off the ignition, the fuel pump should not work.
- If the fuel pump continues to run, test the fuel pump supply voltage circuit for a short to power. If the circuit/connection test is normal, replace the fuel pump relay.
2. Check fuel pump fuse. The fuse must not be open.
- If the fuel pump fuse is open, test the fuel pump supply voltage circuit for a short to ground. If the circuit and connections are OK, replace the fuel pump.
3. Switch off the ignition, remove the fuel pump relay from the electrical box.
4. Ignition ON, test battery voltage between the B+ circuit of the fuel pump relay and ground.
- If the voltage is less than B+, repair the open/high resistance of the B+ voltage circuit of the fuel pump relay.
5. Connect 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 is not working, check for the following conditions:
- Open/high resistance in fuel pump supply voltage circuit
- Open/high resistance in fuel pump ground circuit
- If the indicated circuit and connections are OK, replace the fuel pump.
6. If all circuits/connections test normal, test or replace the fuel pump relay.
Component testing
1. Measure the resistance between terminals 85 and 86 of the fuel pump relay; resistance should be in the range of 70 - 110 ohms.
- If 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; 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 20A fused jumper wire 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; resistance must be less than 2 ohms.
- If resistance is greater than 2 ohms, replace the fuel pump relay.
Fuel system diagnostics
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
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 will turn off the fuel pump relay after 2 seconds. The control module maintains the fuel pump relay on while the ignition reference pulses are being received. The control module will deactivate the fuel pump relay after 2 seconds if the ignition reference stops and the ignition remains on.
The fuel system is of a non-return, on-demand design. A fuel pressure regulator is included with the primary fuel tank module, eliminating the need for a fuel return line from the engine. The non-return fuel system reduces the temperature inside the fuel tank by not returning hot fuel from the engine to the fuel tank. Lowering the temperature in the fuel tank reduces the emission of fuel vapors.
A turbine-type electric fuel pump is attached to the primary fuel tank module inside the fuel tank. The fuel pump delivers fuel at high pressure through the fuel filter, through the fuel pressure regulator and fuel supply line to the fuel injection system. The fuel pressure regulator has a tee that diverts the required amount of fuel to the fuel rail while unused fuel is returned to the primary fuel tank module reservoir. The primary fuel tank module has a return flow control valve. The check valve and fuel pressure regulator maintain fuel pressure in the fuel supply line and fuel rail to reduce engine start 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 inlet chamber of the pump, is diverted to the primary jet pump and the secondary jet pump through a restrictive diaphragm located in the pump cover. The primary jet pump fills the primary fuel tank module reservoir. The secondary jet pump draws fuel from the secondary compartment of the fuel tank through the fuel transfer tube into the primary compartment of the fuel tank due to the effect of the Venturi tube.
Diagnostic Information
- If fuel runs out before the fuel gauge reaches zero, this may indicate a problem with the siphon jet pump or the connecting lines between the fuel tanks. Inspect for blockages, foreign objects, or flow restrictions in all relevant components.
- If the fuel runs out before the fuel gauge reaches zero, this may be due to a faulty fuel gauge. Inspect the float arm for sticking or obstruction.
Circuit/System Testing
Important:
- Inspect the fuel system for damage and external leaks before proceeding further.
- Before proceeding further, make sure that there is enough fuel in the fuel tank.
- It may take several activations of the fuel pump relay to reach maximum fuel pressure.
- DO NOT START the engine.
1. Ignition ON, use a scan tool 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, refer to Fuel Pump Electrical Circuit Diagnosis.
2. Turn off the ignition, turn off all accessories, install a fuel pressure gauge.
3. Ignition ON, use a scan tool to command the fuel pump relay to turn on. Check that the 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 mixture, refer to Symptoms - Engine Controls.
Circuit / system test
1. Turn the ignition on, 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:
- Restriction of the section of the supply fuel line
- Clogged or clogged fuel filter
- Clogged or clogged strainer
- Fuel level float stuck or clinging to obstacles
- Clogged jet siphon pump
- Clogged transfer lines between fuel tanks
- Faulty fuel pressure regulator
- Poor connections at wiring harness connectors and fuel pump ground circuits
- If malfunctions are found, take corrective action.
- If all components are OK, replace the fuel pump.
Important: When the fuel pump is turned off, the fuel pressure may change slightly. After stopping the fuel pump, the fuel pressure should stabilize and remain constant.
2. Make sure that the fuel pressure decreases no faster than 34 kPa (5 psi) in 1 minute.
- If the fuel pressure drops faster than the specified value, perform the following procedure:
- Switch off ignition, relieve fuel pressure.
- Install fuel gauge.
- Make sure that the fuel pressure decreases no faster than 34 kPa (5 psi) in 1 minute.
- If the fuel pressure remains constant, replace the fuel pump.
- If fuel pressure drops, find and replace the leaking fuel injector.
3. Relieve fuel pressure to 69 kPa (10 psi). Make sure that the fuel pressure drops by no more than 14 kPa (2 psi) in 5 minutes.
- If the fuel pressure drops faster than specified, replace the fuel pump.
4. Remove fuel 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 readings indicate a lean mixture, check/investigate for the following:
- Restriction of the section of the supply fuel line
- Clogged fuel filter
- Clogged jet siphon pump
- Clogged transfer lines between fuel tanks
- Faulty fuel pressure regulator
- Poor connections at wiring harness connectors and fuel pump ground circuits
- If no fault is found on all components and the scan tool indicates a lean mixture, replace the fuel pump.
Checking the fuel injector coil
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
Description of circuits / systems
The control module provides the appropriate injector activation pulses to all cylinders. The ignition voltage is fed directly to the fuel injectors. The control module controls the operation of each fuel injector by grounding the control circuit through the built-in semiconductor switch - driver. High or low resistance in the fuel injector coil winding will degrade engine performance. The fuel injector control circuit DTC may not set, but a misfire may occur. The temperature also affects the winding of the ignition coils. The resistance of the fuel injector coil windings increases as the temperature of the fuel injectors rises.
Diagnostic Information
- To find out which injector is causing this condition, it is helpful to refer to the counters or the misfire chart.
- If the vehicle is operated over wide temperature ranges, it helps to identify the fuel injector causing this deviation.
- Perform a fuel injector coil test under the conditions the customer experienced the problem. Deviation in the operation of fuel injectors may occur at a certain temperature or under certain conditions.
Component testing
Check the resistance of all fuel injector coils using one of the following methods:
- If the reading of the engine coolant temperature sensor is between 10-32°C (50-90°F), the resistance of each fuel injector coil should be 11-14 ohms.
- If any injector coil resistance is not within 11-14 ohms, replace that injector.
- If the reading of the engine coolant temperature sensor is not between 10-32°C (50-90°F), measure and record the coil resistance of each fuel injector with a digital multimeter. Subtract the smallest value from the largest resistance value. 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 paragraph "Injector balance check".
- If the difference is greater than 3 ohms, sum all the resistances of the fuel injector coils to obtain the total resistance value. Divide the total resistance value by the number of fuel injectors to get the average resistance value. Subtract the smallest and largest resistance values from the average resistance value. Replace the fuel injector with the largest difference in resistance above or below the average.
Injector balance check
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
Example of checking the balance of injectors
Cylinder
|
1
|
2
|
3
|
4
|
5
|
6
|
First value
|
360 kPa (52 psi)
|
360 kPa (52 psi)
|
360 kPa (52 psi)
|
360 kPa (52 psi)
|
360 kPa (52 psi)
|
360 kPa (52 psi)
|
Second meaning
|
195 kPa (28 psi)
|
138 kPa (20 psi)
|
195 kPa (28 psi)
|
195 kPa (28 psi)
|
235 kPa (34 psi)
|
195 kPa (28 psi)
|
A fall
|
166 kPa (24 psi)
|
222 kPa (32 psi)
|
166 kPa (24 psi)
|
166 kPa (24 psi)
|
125 kPa (18 psi)
|
166 kPa (24 psi)
|
Medium range: 156..176 kPa (22.5...25.5 psi inch)
|
nozzle is ok
|
Fuel injector pressure drop too high
|
nozzle is ok
|
nozzle is ok
|
Faulty injector - pressure drop too low
|
nozzle is ok
|
Description of circuits / systems
First, the scan tool energizes the fuel pump relay coil. Then, using a tester, each fuel injector is turned on for a certain time to deliver a measured amount of fuel to the intake manifold. This creates a pressure drop in the system that can be recorded and used to compare injectors.
Diagnostic Information
- To find out which injector is causing this condition, it is helpful to refer to the counters or the misfire chart.
- If the vehicle is operated over wide temperature ranges, it helps to identify the fuel injector causing this deviation.
- Perform a fuel injector balance test under the conditions in which the problem was experienced by the customer. Deviation in the operation of fuel injectors may occur at a certain temperature or under certain conditions.
Component testing
Injector balance check
1. Ignition ON, use a scan tool to verify that the 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 down before proceeding further.
2. Switch off the ignition, install a fuel pressure gauge.
3. Turn on the ignition, make sure that the fuel pressure is between 380-410 kPa (55-60 psi).
- If the fuel pressure is not within the specified range, carry out further diagnostics of the fuel system according to the section "Fuel system diagnostics".
4. Monitor the fuel gauge for 1 minute. Make sure that the fuel pressure has decreased by no more than 34 kPa (5 psi).
- If the fuel pressure drops by more than 34 kPa (5 psi), carry out further diagnostics of the fuel system according to the section "Fuel system diagnostics".
Note: To prevent engine stall, DO NOT REPEAT any part of this test without first starting the engine.
5. Connect the fuel injector tester to the fuel injector by setting the current switch on the fuel injector tester to Balance Test 0.5-2.5 A.
6. Use a scan tool to command the fuel pump relay to turn on and after fuel pressure stabilizes, record the fuel pressure on the fuel gauge. This will be the first pressure reading.
Important:
- Repeat this step for each fuel injector to get the pressure drop for each fuel injector.
- After the end of the pulses to the fuel injector, the fuel pressure may increase. Write down the value of the fuel pressure immediately after the end of the pulses to the fuel injector. 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 pulses to the fuel injector. This will be the second pressure reading.
8. Add up all pressure drops; resulting in a 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 nozzle and the average pressure drop must not exceed 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
Attention! Before checking the fuel tank for leaks, place a powder fire extinguisher nearby (class B). Before removing a fuel tank that is suspected to be leaking, make sure that no fuel is leaking from the fuel lines or fuel pipes into the tank. After removing the tank, make sure that no fuel is leaking around the O-ring of the fuel gauge sensor. Failure to do so may result in an accident.
Fault diagnostic information
Before using this diagnostic procedure, it is essential to run a diagnostic check on the system.
Description of circuits / systems
Checking the fuel tank for leaks detects fuel or fuel vapor leaking from the fuel tank. Fuel vapor leaks above the fuel level will be detected at the completion of one EVAP system diagnostic cycle. The MIL will illuminate after 2 EVAP system diagnostic cycles if the leak is large, or up to 8 EVAP system diagnostic cycles if the leak is small, only if there is a malfunction.
Diagnostic Information
- Carry out operation of the car in conditions under which the user experienced problems. At high temperatures, the amount of fuel vapor can increase so much that the fuel vapor in the canister reaches saturation. In this case, fuel vapors will be released into the atmosphere. After starting the engine and turning on the purge of the fuel vapor recovery system, the release of fuel vapors into the atmosphere will stop.
- If the problem is intermittent, wiggling the evaporative emission system pipes and fuel lines may help.
- If the fuel level is low, liquid fuel leakage may not occur.
Circuit/System Testing
1. Check that the fuel tank and fuel lines are not damaged or leaking.
- If malfunctions are found, take corrective action.
2. Ignition ON, use a scan tool to command the fuel pump relay to turn on. Make sure the fuel lines are not leaking.
- If malfunctions are found, take corrective action.
Important: Refer to the J 41413-200 Gasoline Evaporative Emission System Tester instruction manual for detailed instructions.
3. Switch off the ignition, attach J 41413-200 and GE-41415-50 to the fuel filler neck.
4. Use the scan tool to command the EVAP vent valve to close.
5. Set the nitrogen/smoke valve to the nitrogen supply position and check that there is no fluid leakage from the pressurized system.
- If a leak is found, take corrective action.
Important: It may be necessary to partially lower the fuel tank.
6. Use J 41413-200 to apply smoke to the EVAP system. Make sure there are no vapor leaks in the following places:
- Fuel tank, fill limit vent valve, relief valve, staged vent valve
- Fuel Gauge Housing, Fuel Gauge Seal, Fuel Line, Evaporative Emission System Tubing
- Fuel tank pressure sensor seal
- Fuel filler neck and hose
- If a leak is noticed, take steps to eliminate it.
Component testing
Injector balance check
1. Ignition ON, use a scan tool to verify that the 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 down before proceeding further.
2. Switch off the ignition, install a fuel pressure gauge.
3. Turn on the ignition, make sure that the fuel pressure is between 380-410 kPa (55-60 psi).
- If the fuel pressure is not within the specified range, carry out further diagnostics of the fuel system according to the section "Fuel system diagnostics".
4. Monitor the fuel gauge for 1 minute. Make sure that the fuel pressure has decreased by no more than 34 kPa (5 psi).
- If the fuel pressure drops by more than 34 kPa (5 psi), carry out further diagnostics of the fuel system according to the section "Fuel system diagnostics".
Note: To prevent engine stall, DO NOT REPEAT any part of this test without first starting the engine.
5. Connect the fuel injector tester to the fuel injector by setting the current switch on the fuel injector tester to Balance Test 0.5-2.5 A.
6. Use a scan tool to command the fuel pump relay to turn on and after fuel pressure stabilizes, record the fuel pressure on the fuel gauge. This will be the first pressure reading.
Important:
- Repeat this step for each fuel injector to get the pressure drop for each fuel injector.
- After the end of the pulses to the fuel injector, the fuel pressure may increase. Write down the value of the fuel pressure immediately after the end of the pulses to the fuel injector. 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 pulses to the fuel injector. This will be the second pressure reading.
8. Add up all pressure drops; resulting in a 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 nozzle and the average pressure drop must not exceed 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.
Diagnosis of the control system of the valve for changing the geometry of the intake manifold
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
Description of circuits / systems
Intake manifold geometry control valve (IMRC) changes the configuration of the intake manifold chamber. When the IMRC valve is open, the intake manifold is a single large chamber.
When the IMRC valve is closed, the intake manifold splits into 2 smaller chambers. The IMRC valve improves engine performance at low and high speeds.
The ignition voltage is applied directly to the IMRC solenoid. The ECM controls the valve by grounding the control circuit through a semiconductor device, the so-called. drivers. The device is equipped with a feedback circuit that increases the voltage. The ECM can detect an open control circuit, a short to ground, or a short to voltage by monitoring the feedback voltage.
Diagnostic Information
Check the IMRC solenoid for signs of valve hitting the intake manifold. This state may be temperature dependent.
Circuit/System Testing
Ignition ON, obtain DTC information with a scan tool. Verify that DTCs P2008, P2009 or P2010 are not set.
- If any of the DTCs listed are set, refer to the relevant DTC information for further diagnosis.
Circuit / system test
1. Ignition OFF, remove the IMRC valve control solenoid from the intake manifold by disconnecting the electrical connector.
2. Ignition ON, use a scan tool to command the IMRC solenoid on and off. Verify that the IMRC solenoid works in both directions.
- If the IMRC solenoid does not work in both directions, replace the IMRC solenoid.
3. Inspect the inside of the intake manifold for the following:
- A layer of soot that interferes with the movement of the IMRC valve
- Burst interfering with IMRC valve movement
- Foreign bodies interfering with IMRC valve movement
- If a problem is found, take corrective action.
4. Clean or replace upper intake manifold.
Diagnostics of the electronic ignition system
Fault diagnostic information
Perform a Diagnostic System Check before using this diagnostic procedure.
Description of circuits / systems
Ignition coils are energized with ignition 1 voltage. The ECM applies ground to the ignition coil control circuits. When the ECM opens "mass" primary ignition coil, the magnetic field of the coil disappears. The disappearance of the magnetic field causes a high voltage to appear on the secondary winding, which creates a discharge on the spark plugs. Ignition sequence and timing are controlled by the ECM.
Diagnostic Information
- The ignition coils of each row of cylinders have independent fuses. If the fuse opens or the ignition 1 voltage circuit is interrupted between the fuse and the cable connection, all of the ignition coils in the engine bank will stop working. If the ground circuit is broken at the engine block, the ignition coils stop working on one bank of engine cylinders.
- Inspect the ignition coils, checking if any devices were installed after the vehicle was sold. Connecting foreign devices to the ignition coil circuits can cause problems with the ignition coils.
Circuit / system test
Important: This diagnostic procedure should only be performed if you came here from a Misfire DTC or Diagnostic Troubleshooting "The crankshaft turns, but the engine does not start".
1. Ignition OFF, disconnect the harness connector from the ignition coil.
2. Ignition ON, test under load for battery voltage between the ignition coil 1 voltage circuit and ground.
- If the voltage is less than B+, repair the short to ground or open/high resistance in the ignition coil 1 voltage circuit.
3. Ignition OFF, check the resistance between the ground circuit of the ignition coil and the negative battery terminal; resistance must be below 5 ohms.
- If greater than 5 ohms, repair the open/high resistance in the ignition coil ground circuit.
4. If no fault is found when testing all circuits/connections, replace the ignition coil.