knocking under boost?
knocking under boost?
I was having some issues with my primary o2 so I replaced it and the code is gone now. I got a tune from a friend a few months back. the timing chain tensioner was rattling so I replaced that too. It seems to run good now, boosts fine and still hauls ass but I am still knocking as soon as my boost kicks in and then it gradually corrects itself. my afr's are fine I can't figure out why it's knocking. I tried new plugs and even cam 2 and it still does it. I have stock injectors but they're running at a silly duty cycle from the tune so I figured it may be that? I def need advice.
Some stuff for you to consider
Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations
Test for incorrect fuel pressure.
Test the fuel injectors.
Inspect for a contaminated fuel condition
Any water intrusion in the heated oxygen sensor (HO2S) connector
- An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage .
- Any vacuum leaks
- Incorrect fuel pressure
- Any restricted fuel injectors
- Fuel contamination
- Any vacuum hoses that are split, kinked, or improperly connected
• Inspect for an engine coolant temperature (ECT) sensor that has shifted in value .
• Remove spark plugs and inspect for the following conditions:
- Correct heat range
- Wet plugs
- Cracks
- Wear
- Improper gap
- Burned electrodes
- Heavy deposits
- Verify that the spark plugs are of the correct type.
• Inspect for proper ignition system output. Refer to Electronic Ignition (EI) System Diagnosis .
• An improper spark plug gap will cause a driveability condition. Gap the spark plugs using a wire gage gap tool.
• Determine the cause of the fouling before replacing the spark plugs.
• Inspect for damaged or misaligned spark plug boots.
• Inspect the electronic ignition (EI) module for proper ground connection.
Inspect for obvious overheating conditions:
• Low engine coolant--Refer to Loss of Coolant .
• A faulty thermostat--Refer to Thermostat Diagnosis .
• A restricted air flow to the radiator or restricted coolant flow through the radiator
• An inoperative electric cooling fan--Refer to Cooling Fan Malfunction .
• Proper tension on the drive belts
Inspect for the following engine mechanical conditions:
• Excessive oil in combustion chamber or leaking valve seals--Refer to Oil Consumption Diagnosis .
• High cylinder compression--Refer to Engine Compression Test .
• Combustion chambers for excessive carbon buildup--Clean the combustion chamber by using top engine cleaner. Follow the instructions on the can.
• Incorrect camshaft timing
• Inspect for incorrect basic engine parts. Inspect the following components:
- The camshaft--Refer to Camshaft Cleaning and Inspection .
- The cylinder heads--Refer to Cylinder Head Cleaning and Inspection .
- The pistons, etc.--Refer to Cylinder Head Cleaning and Inspection .
• Refer to Symptoms - Engine Mechanical
Inspect the powertrain control module (PCM) grounds for being clean, tight, and in the proper locations
Test for incorrect fuel pressure.
Test the fuel injectors.
Inspect for a contaminated fuel condition
Any water intrusion in the heated oxygen sensor (HO2S) connector
- An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage .
- Any vacuum leaks
- Incorrect fuel pressure
- Any restricted fuel injectors
- Fuel contamination
- Any vacuum hoses that are split, kinked, or improperly connected
• Inspect for an engine coolant temperature (ECT) sensor that has shifted in value .
• Remove spark plugs and inspect for the following conditions:
- Correct heat range
- Wet plugs
- Cracks
- Wear
- Improper gap
- Burned electrodes
- Heavy deposits
- Verify that the spark plugs are of the correct type.
• Inspect for proper ignition system output. Refer to Electronic Ignition (EI) System Diagnosis .
• An improper spark plug gap will cause a driveability condition. Gap the spark plugs using a wire gage gap tool.
• Determine the cause of the fouling before replacing the spark plugs.
• Inspect for damaged or misaligned spark plug boots.
• Inspect the electronic ignition (EI) module for proper ground connection.
Inspect for obvious overheating conditions:
• Low engine coolant--Refer to Loss of Coolant .
• A faulty thermostat--Refer to Thermostat Diagnosis .
• A restricted air flow to the radiator or restricted coolant flow through the radiator
• An inoperative electric cooling fan--Refer to Cooling Fan Malfunction .
• Proper tension on the drive belts
Inspect for the following engine mechanical conditions:
• Excessive oil in combustion chamber or leaking valve seals--Refer to Oil Consumption Diagnosis .
• High cylinder compression--Refer to Engine Compression Test .
• Combustion chambers for excessive carbon buildup--Clean the combustion chamber by using top engine cleaner. Follow the instructions on the can.
• Incorrect camshaft timing
• Inspect for incorrect basic engine parts. Inspect the following components:
- The camshaft--Refer to Camshaft Cleaning and Inspection .
- The cylinder heads--Refer to Cylinder Head Cleaning and Inspection .
- The pistons, etc.--Refer to Cylinder Head Cleaning and Inspection .
• Refer to Symptoms - Engine Mechanical
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Sl0wbaltSS
2.0L LNF Performance Tech
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Nov 21, 2018 11:11 PM



