Engine Controls - Trouble Shooting - No Codes - 2.2L: Diagnosis Pontiac Sunfire I

PRELIMINARY INSPECTION

1. Verify on-vehicle diagnostics are working by performing «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
2. Ensure PCM grounds are clean, tight, and properly located.
3. Check vacuum hoses for splits, kinks, leaks, restrictions and proper connections. Ensure vacuum hoses are correctly routed as shown on vehicle emission control information label.
4. Remove the air filter element and check for dirt and for restrictions.
5. Check for air leaks at all intake manifold sealing surfaces.
6. Check ignition wires for cracking, hardness, proper routing and carbon tracking.
7. Check wiring for proper connections and routing, pinches, burns, cuts or other damage.
8. Ensure PCM and MIL are functioning properly.
9. Ensure there are no DTCs stored, or only intermittent DTCs are present.
10. Ensure fuel control system is operating properly. Go to «FUEL SYSTEMS (GASOLINE)»(ref-153404-S11758687802003040400000) in SYSTEM & COMPONENT TESTING - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
11. Perform fuel system pressure test. Go to «FUEL PRESSURE TEST»(ref-153407-S10485392962003050500000) under FUEL SYSTEMS (GASOLINE) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
12. Perform a careful visual inspection of all systems.

After all checks have been performed, verify customer complaint and locate correct symptom. Check items indicated under that symptom. Not all items listed under each symptom apply to all models and systems. These procedures will normally recommend testing of a specific system or component, such as EGR, ignition, TCC, etc. Go to SYSTEM & COMPONENT TESTING - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article for appropriate test procedures.

Note. If PCM displays data but engine fails to start, go to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.

SYMPTOMS

Before proceeding with any symptom diagnosis, perform all steps under PRELIMINARY INSPECTION .

SYMPTOM DIAGNOSIS - ENGINE CONTROLS

Note. For exhaust system symptoms, go to DIAGNOSTIC STARTING POINT - ENGINE EXHAUST .

Symptom checks should not be used unless symptom occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in appropriate BASIC DIAGNOSTIC PROCEDURES and SELF-DIAGNOSTICS articles were performed before diagnosing a symptom. Symptoms available for diagnosis include

Symptoms available for diagnosis include

1. «BACKFIRES»(ref-153405-S27424646542003040400000)
2. «CUTS OUT, MISSES»(ref-153405-S33357355522003040400000)
3. «DETONATION/SPARK KNOCK»(ref-153405-S11438623882003040400000)
4. «DIESELING/RUN-ON»(ref-153405-S09872640972003040400000)
5. ENGINE CRANKS BUT DOES NOT RUN - See «NO-START DIAGNOSIS»(ref-153407-S39462087592003040400000) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
6. «HESITATION, SAG OR STUMBLE»(ref-153405-S16062461682003040400000)
7. «LACK OF POWER, SLUGGISH OR SPONGY»(ref-153405-S38951859552003040400000)
8. «POOR FUEL ECONOMY»(ref-153405-S06465778002003040400000)
9. «POOR FUEL FILL QUALITY»(ref-153405-S27611437572003040400000)
10. «ROUGH, UNSTABLE OR INCORRECT IDLE & STALLING»(ref-153405-S30329885782003040400000)
11. «VEHICLE SURGES OR CHUGGLES»(ref-153405-S09246720392003040400000)

DIAGNOSTIC STARTING POINT - ENGINE EXHAUST

Begin the system diagnosis by reviewing the system description under EXHAUST SYSTEM in THEORY & OPERATION - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Reviewing the information will help determine the correct symptom diagnostic procedure when a malfunction exists. It will also help you determine if the condition described by the customer is normal operation. Go to SYMPTOM DIAGNOSIS - ENGINE EXHAUST to identify the correct procedure for diagnosing the system.

Visual/Physical Inspection

1. Check for aftermarket or non-OEM devices such as, but not including; tailpipe extensions, headers, and exhaust cutouts. This could affect the operation and proper performance of the exhaust system.
2. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, engine temperature, engine load, and frequency of concern.
3. Check the easily accessible or visible system components for obvious damage or conditions which could cause any symptom.

Symptom Definition

Fuel ignites in intake manifold or in exhaust system, making a loud popping noise.

1. Go to «PRELIMINARY INSPECTION»(ref-153405-S03513129882003040400000) before continuing.

Additional Inspections

1. Visually and physically check the vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label.
2. Check the intake manifold and the exhaust manifold passages for casting flash.
3. Check the exhaust system for damaged or collapsed pipes. Check mufflers for heat distress or possible internal failure. Check the catalytic converter for plugged condition. Go to «RESTRICTED EXHAUST»(ref-153405-S10795551862003051300000) .
4. Electromagnetic Interference (EMI) on the reference circuit can cause an engine miss condition. A scan tool can usually detect EMI by monitoring the engine RPM. A sudden increase in RPM with little change in actual engine RPM change may indicate that EMI is present. If a problem exists, check for high voltage components near the ignition control circuits.

Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. This condition is not normally felt above 1500 RPM or 30 MPH. The exhaust has a steady spitting sound at idle or low speed.

Go to PRELIMINARY INSPECTION before continuing.

1. Check the exhaust system for damaged or collapsed pipes. Check mufflers for heat distress or possible internal failure. Check for plugged or restricted catalytic converters. Go to «RESTRICTED EXHAUST»(ref-153405-S10795551862003051300000) .

A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks which change with amount of acceleration.

Preliminary Inspections

1. Go to «PRELIMINARY INSPECTION»(ref-153405-S03513129882003040400000) before continuing.
2. If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicles minimum octane requirements. Road test the vehicle and re-evaluate the vehicles performance.

1. Check the Park/Neutral Position (PNP) switch operation.
2. Check the Transmission Torque Converter Clutch (TCC) operation. The TCC applying too soon can cause the engine to spark knock. Go to appropriate DIAGNOSIS article AUTOMATIC TRANSMISSIONS.

Engine continues to run after ignition is turned off but runs very rough. If engine runs smoothly, check ignition switch and adjustment.

1. Go to «PRELIMINARY INSPECTION»(ref-153405-S03513129882003040400000) before continuing.
2. If there are no engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicles minimum octane requirements. Road test the vehicle and re-evaluate the vehicles performance.

An exhaust leak may show stains at the area of the leak. The leak may be felt by holding a hand close to the suspected areas or using a smoke pencil. The leak may make a popping or hissing noise.

Diagnosis

EXHAUST LEAKAGE DIAGNOSIS

An audible or physical noise due to a faulty component or damaged components causing a loose or misaligned exhaust system resulting in a rattle or vibration noise, i.e. buzz, groan or hum.

EXHAUST NOISE DIAGNOSIS

Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

Go to PRELIMINARY INSPECTION before continuing.

Verify that the driver is using the correct starting procedure as described in the owners manual.

Momentary lack of response when accelerator is pushed down. Condition occurs at all vehicle speeds or usually occurs when taking off from a stop. If severe enough, may cause engine to stall.

Go to PRELIMINARY INSPECTION before continuing.

Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.

Go to PRELIMINARY INSPECTION before continuing.

1. Check the exhaust system for the following possible restrictions: The exhaust system for damaged or collapsed pipes. The mufflers for heat distress or internal failure. Go to «RESTRICTED EXHAUST»(ref-153405-S10795551862003051300000) .
2. Check the Transmission Torque Converter Clutch (TCC) operation. The TCC applying too soon can cause the engine to spark knock. Go to appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

Fuel economy, as measured by an actual road test, is noticeably lower than expected Also, fuel economy is noticeably lower than the economy was on this vehicle at one time, as previously shown by an actual road test.

Go to PRELIMINARY INSPECTION before continuing.

Discuss driving habits with the owner. Is the A/C ON or the Defroster mode ON full time? Are the tires at the correct pressure? Are the wheels and tires the correct size? Are there excessively heavy loads being carried? Is the acceleration rate too much, too often? Remove the air filter element and check for dirt or for restrictions.

1. Visually and physically check the vacuum hoses for splits, kinks, and proper connections and routing as shown on Vehicle Emission Control Information label.
2. Check the transmission Torque Converter Clutch (TCC) operation. The scan tool should indicate a RPM drop, when the system commands the TCC ON. Go to appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
3. Check the exhaust system for a possible restriction. Check for damaged or collapsed pipes, mufflers for heat distress or possible internal failure and catalytic converters for a plugged condition. Go to «RESTRICTED EXHAUST»(ref-153405-S10795551862003051300000) .
4. Check the brake system for dragging or improper operation. Go to appropriate DISC & DRUM article in BRAKES. Verify that the vehicle operator does not drive with a foot on the brake pedal.

During the fueling process a continual, occasional or no fuel nozzle shut-off condition has occurred.

Diagnostic Procedure

1. Did you verify the customers complaint? If yes, go to next step.
2. Did you review the exhaust symptom diagnostic information and perform the necessary inspections? If yes, go to next step. If no, go to «DIAGNOSTIC STARTING POINT - ENGINE EXHAUST»(ref-153405-S04216481072003051300000) .
3. Is the system equipped with dual exhaust? If yes, go to «DIAGNOSTIC AIDS»(ref-153405-S28515396642003051300000) . If no, go to next step.
4. Remove the HO2S that is in front of and closest to the catalytic converter. Install the Exhaust Back Pressure Gauge (J 35314-A) in place of the HO2S. Start the engine. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed 2 psi (14 kPa)? If yes, go to next step. If no, go to step 8 .
5. Turn engine ignition switch to LOCK position. Remove the Exhaust Back Pressure Gauge still installed increase and monitor engine speed to 2000 RPM. Re-install the HO2S sensor. Remove the post-catalytst HO2S sensor. Install the Exhaust Back Pressure Gauge in place of the post HO2S sensor. Start the engine. Increase and monitor the engine speed at 2000 RPM. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed 2 psi (14 kPa)? If yes, go to next step. If no, to step 7 .
6. Check the exhaust system for damage in the exhaust pipe, debris in the exhaust pipe, muffler or resonator internal failure or two-layer exhaust pipe separation. Repair as necessary. After repair, go to step 8 .
7. Replace the catalytic converter. After repair, go to next step.
8. Remove the exhaust back pressure gauge and reinstall the HO2S sensor. Using a scan tool, clear any DTCs. Road test the vehicle to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step 2 .

Diagnostic Aids

For dual exhaust systems a quick check of exhaust flow will help determine which side of the exhaust system is restricted. The side that has less exhaust flow is the side that will be suspect, and diagnosis should begin there.

Engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.

Go to PRELIMINARY INSPECTION before continuing.

Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal position.

1. Visually and physically check vacuum hoses for splits, kinks, and proper connections and routing as shown on the Vehicle Emission Control Information label.
2. Check the transmission Torque Converter Clutch (TCC) operation. A TCC applying too soon can cause the engine to spark knock. Go to appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.
3. Test the A/C clutch for proper operation. Go to appropriate MANUAL A/C-HEATER SYSTEMS in AIR CONDITIONING & HEATING article.
4. Check the exhaust system for possible restrictions. Go to «RESTRICTED EXHAUST»(ref-153405-S10795551862003051300000) .