The car ran well for 2 weeks and started to misfire. This time I had a code for O2 sensor stuck lean and LTFT on bank 1 had grown to over 35%. This makes sense since the original misfire issue seemed to be the cylinders being drowned in fuel. I changed the upstream O2 sensor and reset learned fuel mixture. I also changed the MAP sensor since it was inexpensive and easy to do.
The car runs fine but I have not put many miles on it. LTFT ranges between 4% and 15% after only a few short trips. Strangely, the higher reading is bank 2 that never had misfires. I have noticed that under throttle the readings go down, well under 10%. They seem highest at idle. STFT has minor swings +/-.
Should I be trying to achieve a LTFT value of near 0. If it does not get worse over time should I consider this normal? I'll continue to look for a vacuum leak
The car ran well for 2 weeks and started to misfire. This time I had a code for O2 sensor stuck lean and LTFT on bank 1 had grown to over 35%. This makes sense since the original misfire issue seemed to be the cylinders being drowned in fuel. I changed the upstream O2 sensor and reset learned fuel mixture. I also changed the MAP sensor since it was inexpensive and easy to do.
The car runs fine but I have not put many miles on it. LTFT ranges between 4% and 15% after only a few short trips. Strangely, the higher reading is bank 2 that never had misfires. I have noticed that under throttle the readings go down, well under 10%.
They seem highest at idle. STFT has minor swings +/-.
Should I be trying to achieve a LTFT value of near 0. If it does not get worse over time should I consider this normal?
I'll continue to look for a vacuum leak
> Compare both banks LTFT only at WARM IDLE.
0 to 5% is best.
10 is borderline
15 is concern (unless custom flash)
You need both Upstream sensors equally new, not one bank only.
Once you have meaningful measures you can wonder about causes and solutions.
0 to 5% is best.
10 is borderline
15 is concern (unless custom flash)
You need both Upstream sensors equally new, not one bank only.
Once you have meaningful measures you can wonder about causes and solutions.
both upstream o2 sensors are new. While driving readings are between 5% and 10%. Readings at warm idle while in closed loop are where they get over 10% to 15%. Bank A tends to be higher than B. No tunes, all stock.
both upstream o2 sensors are new. While driving readings are between 5% and 10%. Readings at warm idle while in closed loop are where they get over 10% to 15%. Bank A tends to be higher than B. No tunes, all stock.
LTFT driving numbers are meaningless without context... idle only!
At least we can tell you have a lean engine not getting enough fuel!
Hard data taken with engine fully warmed up at idle using a Launch device. I have never found a way to get the recorded data and charts off the device though so this is a snapshot.
I see no counter that shows low pressure fuel pump pressure but earlier in the process I used a gauge on the fuel rail before the high pressure pumps and got 60 lbs.
The engine is running fine with no fault codes. Acceleration is great and idle is smooth. The high LTFT numbers have me concerned. With the sides being unequal I have some concern this could be a product of the beginnings of timing chain stretch. while driving, these numbers go well below 10% but bank 2 is always a little higher than bank 1.
Also, it looks to me like all the vacuum operated devices are hooked up to the vacuum pumps. I did not see any vacuum lines attached to the intake manifold other than the fuel tank purge valve which did not show any signs of cracking or deterioration.
Hard data taken with engine fully warmed up at idle using a Launch device. I have never found a way to get the recorded data and charts off the device though so this is a snapshot.
I see no counter that shows low pressure fuel pump pressure but earlier in the process I used a gauge on the fuel rail before the high pressure pumps and got 60 lbs.
The engine is running fine with no fault codes. Acceleration is great and idle is smooth. The high LTFT numbers have me concerned. With the sides being unequal I have some concern this could be a product of the beginnings of timing chain stretch. while driving, these numbers go well below 10% but bank 2 is always a little higher than bank 1.
Also, it looks to me like all the vacuum operated devices are hooked up to the vacuum pumps. I did not see any vacuum lines attached to the intake manifold other than the fuel tank purge valve which did not show any signs of cracking or deterioration.
Check out @sprihadi's posts on boost leaks. He has a very good description of the vacuum lines.
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