Did the PCV tube solve the 171 and 174 both banks lean? One other question, has anyone ever pulled the oxygen sensor before the cat and made an exhaust backpressure check?
I will give you some information on torque converter characteristics, as well as a bulletin.
#PIP3144C: Poor Acceleration From A Stop Or Detonation In Gear At A Stop - keywords DTC low MIL ping - (Jun 12, 2009)
Subject: Poor Acceleration from a Stop or Detonation in Gear at a Stop
Models: 1996-2009 All General Motors Passenger Cars and Light Duty Trucks
This PI was superseded to update model years and add an important note. Please discard PIP3144B.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Customer concern of poor acceleration, detonation or "ping" at idle in drive or reverse, and/or possible DTC P0101, P0106 and/or P0121 set in the PCM. The vehicle will perform properly after attaining a speed of about 30 - 40 mph. The condition may also be described by the customer or the dealer as a hesitation, stall when putting into gear, surge on acceleration (similar to hitting fuel cut off or rev limiter). The ultimate cause may be a non-holding torque converter stator or damaged stator support shaft within the automatic transmission.
Important Note: Do not follow the below diagnostics until published SI diagnostics have been followed COMPLETELY. If all published SI diagnostics have been exhausted the following information may help in isolating a possible torque converter concern.
The following checks should be performed in the event that normal engine driveability checks have not resolved the detonation or "ping" at idle in drive or reverse, lack of power from a stop, stall, and surge on acceleration and or hesitation complaint.
The IAC counts throttle angle and/or MAP voltage and KPA should be compared to a like vehicle in park and in gear after reaching operating temperature. If the counts and map are high or throttle angle is open excessively in comparison this may be a result of high engine load and a torque converter and or stator support shaft related concern.
If the above information does not lead to resolution, follow torque converter diagnostics listed below:
The transmission oil cooler outlet line (line to the cooler) should be checked for excessive heat. The Tech II scan tool may be helpful on vehicles equipped with the transmission fluid temperature sensor in the cooler line (mainly front wheel drive). On vehicles that do not have the temperature sensor in the cooler line a temperature probe should be used to check the temperature. The temperature readings should be compared to a like vehicle with the same powertrain option content.
A stall test (brake torque) may point to a damaged torque converter; the stall rpm speed will be lower than a like vehicle. However, poor engine performance will also produce a lower stall speed rpm.
If the torque converter stator or stator support is suspect, the transmission should be removed and THE STATOR SUPPORT SHOULD BE INSPECTED FOR SPLINE DAMAGE. If the stator support splines are damaged the transmission should be repaired and new torque converter installed. If damage is not present on the stator support the concern is either internal to the torque converter stator or an engine performance concern.
Torque Converter Diagnosis
The Torque Converter Clutch (TCC) is applied by fluid pressure, which is controlled by a PWM solenoid valve. This solenoid valve is located inside of the automatic transmission assembly. The solenoid valve is controlled through a combination of computer controlled switches and sensors.
Torque Converter Stator
The torque converter stator roller clutch can have two different malfunctions.
" The stator assembly freewheels in both directions.
" The stator assembly remains locked up at all times.
Poor Acceleration at Low Speed
If the stator is freewheeling at all times, the car tends to have poor acceleration from a standstill. At speeds above 50-55 km/h (30-35 mph), the car may act normally. For poor acceleration, you should first determine that the exhaust system is not blocked, and the transmission is in First gear when starting out.
If the engine freely accelerates to high RPM in NEUTRAL, you can assume that the engine and the exhaust system are normal. Check for poor performance in DRIVE and REVERSE to help determine if the stator is freewheeling at all times.
Poor Acceleration at High Speed
If the stator is locked up at all times, performance is normal when accelerating from a standstill. Engine RPM and car speed are limited or restricted at high speeds. Visual examination of the converter may reveal a blue color from overheating.
If the converter has been removed, you can check the stator roller clutch by inserting a finger into the splined inner race of the roller clutch and trying to turn the race in both directions. You should be able to freely turn the inner race clockwise, but you should have difficulty in moving the inner race counterclockwise or you may be unable to move the race at all.
Important: Do not confuse this noise with pump whine noise, which is usually noticeable in PARK, NEUTRAL and all other gear ranges. Pump whine will vary with line pressure.
You may notice a torque converter whine when the vehicle is stopped and the transmission is in DRIVE or REVERSE. This noise will increase as you increase the engine RPM. The noise will stop when the vehicle is moving or when you apply the torque converter clutch, because both halves of the converter are turning at the same speed.
Perform a stall test to make sure the noise is actually coming from the converter:
Place your foot on the brake.
Put the gear selector in DRIVE.
Notice: You may damage the transmission if you depress the accelerator for more than 6 seconds.
Depress the accelerator to approximately 1,200 RPM for no more than six seconds.
A torque converter noise will increase under this load.
Torque Converter Clutch Shudder
The key to diagnosing Torque Converter Clutch (TCC) shudder is to note when it happens and under what conditions.
TCC shudder which is caused by the transmission should only occur during the apply or the release of the converter clutch. Shudder should never occur after the TCC plate is fully applied.
If the shudder occurs while the TCC is applying, the problem can be within the transmission or the torque converter. Something is causing one of the following conditions to occur:
" Something is not allowing the clutch to become fully engaged.
" Something is not allowing the clutch to release.
" The clutch is releasing and applying at the same time.
One of the following conditions may be causing the problem to occur:
" Leaking turbine shaft seals
" A restricted release orifice
" A distorted clutch or housing surface due to long converter bolts
" Defective friction material on the TCC plate
If Shudder Occurs After TCC has Applied
If shudder occurs after the TCC has applied, most of the time there is nothing wrong with the transmission.
As mentioned above, the TCC is not likely to slip after the TCC has been applied. Engine problems may go unnoticed under light throttle and load, but they become noticeable after the TCC apply when going up a hill or accelerating. This is due to the mechanical coupling between the engine and the transmission.
Once TCC is applied, there is no torque converter (fluid coupling) assistance. Engine or driveline vibrations could be unnoticeable before TCC engagement.
Inspect the following components in order to avoid misdiagnosis of TCC shudder. An inspection will also avoid the unnecessary disassembly of a transmission or the unnecessary replacement of a torque converter.
" Spark plugs - Inspect for cracks, high resistance or a broken insulator.
" Plug wires - Look in each end. If there is red dust (ozone) or a black substance (carbon) present, then the wires are bad. Also look for a white discoloration of the wire. This indicates arcing during hard acceleration.
" Coil - Look for a black discoloration on the bottom of the coil. This indicates arcing while the engine is misfiring.
" Fuel injector - The filter may be plugged.
" Vacuum leak - The engine will not get a correct amount of fuel. The mixture may run rich or lean depending on where the leak occurs.
" EGR valve - The valve may let in too much or too little unburnable exhaust gas and could cause the engine to run rich or lean.
" MAP/MAF sensor - Like a vacuum leak, the engine will not get the correct amount of fuel for proper engine operation.
" Carbon on the intake valves - Carbon restricts the proper flow of air/fuel mixture into the cylinders.
" Flat cam - Valves do not open enough to let the proper fuel/air mixture into the cylinders.
" Oxygen sensor - This sensor may command the engine too rich or too lean for too long.
" Fuel pressure - This may be too low.
" Engine mounts - Vibration of the mounts can be multiplied by TCC engagement.
" Axle joints - Check for vibration.
" TP Sensor - The TCC apply and release depends on the TP Sensor in many engines. If the TP Sensor is out of specification, TCC may remain applied during initial engine loading.
" Cylinder balance - Bad piston rings or poorly sealing valves can cause low power in a cylinder.
" Fuel contamination - This causes poor engine performance.
Torque Converter Evaluation and Diagnosis
Replace the torque converter if any of the following conditions exist:
" External leaks appear in the hub weld area.
" The converter hub is scored or damaged.
" The converter pilot is broken, damaged, or fits poorly into the crankshaft.
" You discover steel particles after flushing the cooler and the cooler lines.
" The pump is damaged, or you discover steel particles in the converter.
" The vehicle has TCC shudder and/or no TCC apply. Replace the torque converter only after all hydraulic and electrical diagnoses have been made. The converter clutch material may be glazed.
" The converter has an imbalance which cannot be corrected. Refer to Flexplate/Torque Converter Vibration Test.
" The converter is contaminated with engine coolant which contains antifreeze.
" An internal failure occurs in the stator roller clutch.
" You notice excessive end play.
" Overheating produces heavy debris in the clutch.
" You discover steel particles or clutch lining material in the fluid filter or on the magnet, when no internal parts in the unit are worn or damaged. This condition indicates that lining material came from the converter.
Do not replace the torque converter if you discover any of the following symptoms:
" The oil has an odor or the oil is discolored, even though metal or clutch facing particles are not present.
" The threads in one or more of the converter bolt holds are damaged. Correct the condition with a new thread inset.
" Transmission failure did not display evidence of damaged or worn internal parts, steel particles or clutch plate lining material in the unit and inside the fluid filter.
" The vehicle has been exposed to high mileage only. An exception may exist where the lining of the torque converter clutch dampener plate has seen excess wear by vehicles operated in heavy and/or constant traffic, such as taxi, delivery, or police use.
Lack of Power, Sluggishness, or Sponginess
Lack of Power, Sluggish or Spongy Inspection/Test
DEFINITION: Engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.
" Refer to Powertrain On Board Diagnostic (OBD) System Check.
" Refer to Intermittent Conditions.
" Search for bulletins.
" Test the system fuel pressure. Refer to Fuel System Pressure Test.
" Test the fuel injectors. Refer to Fuel Injector Balance Test, Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F), or Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F).
" Inspect for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
" Inspect any items which can cause an engine to run rich (long term fuel trim is significantly in the negative range). Refer to DTC P0172 Fuel Trim System Rich.
" Inspect any items that can cause an engine to run lean (long term fuel trim is significantly in the positive range). Refer to DTC P0171 Fuel Trim System Lean.
" Using a scan tool, monitor KS system for excessive spark retard activity. Refer to Knock Sensor (KS) System Description.
Important: : The replacement PCM must be programmed.
" If knock retard is above 10 -12 , disconnect the knock sensor, and ground the sensor harness connector. Monitor knock retard on the scan tool, there should be no knock retard present, if knock retard is still present, replace the PCM. Refer to Powertrain Control Module Replacement/Programming.
" Inspect the EGR system for proper operation. Refer to Exhaust Gas Recirculation (EGR) System Description.
" Inspect MAF Sensor and related wiring.
" Inspect the air intake ducts for being collapsed, damaged areas, looseness, improper installation, or leaking especially between the MAF sensor and the throttle body.
" Inspect for proper ignition voltage output using the following steps:
1. Attach the J 26792 spark tester to engine ground.
2. Connect the spark plug end of the spark plug wire to the J 26792 spark tester; leave the other end of the spark plug wire connected to the coil being tested.
3. Connect the spark plug end of the companion spark plug wire to ground.
The companion spark plug wire is the wire attached to the corresponding coil tower.
4. Crank the engine while observing the J 26792 spark tester; a spark should be observed.
5. Repeat the above steps for each coil.
" If spark is not present at the coils, inspect for the following conditions:
- Coils--Cracks, carbon tracking/arcing, or a resistance value outside the specified range.
5000-8000Ã (5K-8KÃ )
- Spark Plug wires--signs of arcing, cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range.
Spark Plug Wire Resistance
600Ã per foot (1 968Ã per meter).
Important: : Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.
- Defective ignition module.
- Ignition system wiring--Loose ignition module feed or ground connection, or damaged system wiring.
" Remove spark plugs and inspect for the following conditions:
- Fouled plugs
- Improper gap
- Burned or damaged electrodes
- Improper heat range or reach
" If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
" Excessive oil in combustion chamber or leaking valve seals--Refer to Base Engine Misfire Diagnosis in Engine Mechanical.
" Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical.
" Inspect for the following incorrect basic engine parts:
- Cylinder heads
- Pistons, etc.
" For more diagnostic aids refer to Base Engine Misfire Diagnosis in Engine Mechanical.
" Inspect the exhaust system for possible restrictions in the following areas:
- The exhaust system for damaged or collapsed pipes
- The mufflers for heat distress or possible internal failure
- The catalytic converter for possible plugged condition--Refer to Restricted Exhaust System Checkand Exhaust Leakage - Not OBD II in Engine Exhaust.
" Inspect for proper TCC operation. Refer to Torque Converter Diagnosis in Automatic Transaxle.
Thursday, February 18th, 2010 AT 10:21 PM