Bank 2 lean at idle and cruise

Tayyab Owner/Technician North Carolina Posted   Latest  
Resolved
Electrical
Programming
2011 Chevrolet Camaro 1LT 3.6L (D LLT) 6-spd
P2179 — System Too Lean Off Idle Bank 2
Lean Bank 2

Hi,

This car is a problem car from another shop. They changed the purge valve, valve cover gaskets, all 4 02s, and mas air flow. When I looked at fuel pressure, it 5 psi before spec and would bleed off immediately. 

I changed fuel pump, fuel trims are better at 20% versus 30%. I installed a new original mas air flow sensor, but same. Bank 1 is perfect only bank 2 is the problem. I even swapped injectors with bank 1 but problem remains on bank 2. I smoke tested the intake, no leaks. 

What other tests can I do? I tested alcohol content which is at 10%. 

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Kevin Technician
Tennessee
Kevin
 

Have you checked compression and ignition components?

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Tayyab Owner/Technician
North Carolina
Tayyab
 

I checked relative compression using a scope and that checked out okay the car idle is fine drives fine starts up fine there are no misfires. Forgot to mention the customer changed the plugs already.

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Kevin Technician
Tennessee
Kevin
 

Do you have a gas analyzer to verify fuel trim activity? If you reset trims back to 0 does the vehicle run poorly.

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Tayyab Owner/Technician
North Carolina
Tayyab
 

When I reset, car runs fine. No gas analyzer.

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Kevin Technician
Tennessee
Kevin
   

Are the o2s the other shop put in quality ones? I would also want to verify o2 operation with a scope, just to be sure you are not dealing with a PCM issue. I agree with the check exhaust for leaks, smoke test your exhaust system. Any TSBs on this problem?

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Andy Diagnostician
Indiana
Andy
 

Check the exhaust for leaks, very small ones, anywhere in the vicinity of the O2 sensors.

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James Owner/Technician
Massachusetts
James
 

Did you check for exhaust leaks?

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Caleb Diagnostician
Indiana
Caleb
 

Can you post a pic of all 4 02 sensor graphs at idle and off idle? These were bad for little exhaust leaks. Also need to check timing and carbon buildup.

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Jimmy Technician
Tennessee
Jimmy
 

After reading everything that has been done I would check cam timing and compare it to the other side. That is provided you have a scope, a pressure transducer would be a plus.

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Todd Diagnostician
Michigan
Todd
 

I agree with Andy and James, exhaust leaks are big on these. Have seen quite a few leaks around oxygen sensor bosses.

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Duane Diagnostician
Maryland
Duane
 

I agree to look at o2 bosses. But for the future, anything like maf sensor and alcohol will affect both banks evenly.

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Tayyab Owner/Technician
North Carolina
Tayyab Resolution
 

One of the bank 2 injectors was leaking externally. Thanks everyone for the help. I think when I swapped injectors, I may have damaged it. Found problem after I drove the vehicle enough for the fuel to pour out.

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Caleb Diagnostician
Indiana
Caleb
 

No misfire???

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