lean bank 1 lean bank 2 code 171 & 174
04-28-2010, 10:24 PM
#1
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lean bank 1 lean bank 2 code 171 & 174 Clear the codes and drive for 10 min-park and then on restart codes come back saying lean bank 1,lean bank 2.my tech says there's no leak after MAF.Has K & N so more o2 getting to TB and PCM is still showing lean.Right now PCM is showing 24% adjustment.What can be done to get the right mix so I don't go
through o2 sensors every 6 months?Need help
through o2 sensors every 6 months?Need help
04-29-2010, 10:17 PM
#7
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Is the 24% correction at idle, accel, cruise or all. If correction goes down off idle, I would lean hard towards a vac leak. More info will get you better help.
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04-30-2010, 01:03 AM
#8
I guess he means LTFTs. Are there driveability issues? If there was insufficient fuel pressure or volume you would have driveability issues especially at WOT. You have to look at what is COMMON to Banks 1 and 2. A vacuum leak at the intake(gasket or hose)? A faulty MAF usually under reports airflow not over reports(lean). Multiple stuck injectors on both banks(not likely)? Fuel filter(maybe and worth checking). How do the STFTs look? Are they switching at 450mVdc?
04-30-2010, 07:42 AM
#10
From what I have seen after re-tuning ALOT of local shops cars, is that when the car has not been tuned properly, the customers seems to go thru alot of 02's and sets the the lean codes as well. Once I get the VE table back in line, I usually install a new set of 02 sensors and all is fine. Get the car tuned properly with a wideband, and install new 02's, and double check all your connections for vacuum leaks. Cammed cars with headers, sometimes the sensors are slow,lazy, depending on where the manufacturer placed the sensors as well.
04-30-2010, 07:09 PM
#12
Not everyone has a smoke maching do to the cost. You can use your scan tool and watch the STFTs while spraying. When you see the STFTs change(go lean due to extra air getting in) look closer at this location. The STFTs will react quicker than you will see a increase in RPM unless it is a big leak.
Last edited by eallanboggs; 05-01-2010 at 04:25 PM.
05-01-2010, 02:57 PM
#13
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Yeah I hear ya on the smoke machine. I tried everything I could think of and hardly drove my car for several months. Cleaned the MAF, replaced the MAF, replaced the front O2 sensors, used starter fluid to try and find a leak, etc. Finally, I took it to my tuner's shop. He charged me two hours labor for finding the leak, repairing the intake manifold, changing out the plugs (they were fouled), and retuning. He even sent me video of the smoke machine operating and the location of the leak at the back of the intake manifold. All for less than $200 (including the new plugs). I wish I had just gone ahead and spent the money with him months ago.
05-01-2010, 03:56 PM
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lean bank 1 lean bank 2 code 171 & 174 Loop Status Closed loop
ECT sensor 94* c
Long term ft bank 1 24%
Long term ft bank 2 24%
Engine speed 795 rpm
Spark 13*
MAF sensor 6.42 g/s
HO2S bank1 sensor 2 120 mV
Engine run timr 00:00:51
Fuel tank level remaining 23%
Distance since DTC cleared 56 km
BARO 101 kpa
Ignition 1 signal 14.1 Volts
Ambient air temp 3* c
Engine load 18 %
Short term ft bank 1 1 %
Short term ft bank 2 4 %
MAP sensor 32 kpa
Vehicle speed sensor 0 km/h
IAT Sensor 32* c
HO2S bank 1 sensor 1 565 mV
HO2S bank 2 sensor 1 80 mV
EVAP purge solenoid command 0%
Warm up since DTC cleared 2 counts
Fuel tank pressure sensor -.02 kpa
Calc. TWC Temp 499* c
TP sensor 1 indicated position 3%
TP desired Angle 5%
Car is an awesome 06' V LS2 ,tech did smoke test-no leak even though everything points to a leak,swapped MAF and o2's,flushed fuel injectors,cleared codes and they return on 2nd restart.Tech is stumped.Can anyone help unlock the mystery.Thanks everyone
ECT sensor 94* c
Long term ft bank 1 24%
Long term ft bank 2 24%
Engine speed 795 rpm
Spark 13*
MAF sensor 6.42 g/s
HO2S bank1 sensor 2 120 mV
Engine run timr 00:00:51
Fuel tank level remaining 23%
Distance since DTC cleared 56 km
BARO 101 kpa
Ignition 1 signal 14.1 Volts
Ambient air temp 3* c
Engine load 18 %
Short term ft bank 1 1 %
Short term ft bank 2 4 %
MAP sensor 32 kpa
Vehicle speed sensor 0 km/h
IAT Sensor 32* c
HO2S bank 1 sensor 1 565 mV
HO2S bank 2 sensor 1 80 mV
EVAP purge solenoid command 0%
Warm up since DTC cleared 2 counts
Fuel tank pressure sensor -.02 kpa
Calc. TWC Temp 499* c
TP sensor 1 indicated position 3%
TP desired Angle 5%
Car is an awesome 06' V LS2 ,tech did smoke test-no leak even though everything points to a leak,swapped MAF and o2's,flushed fuel injectors,cleared codes and they return on 2nd restart.Tech is stumped.Can anyone help unlock the mystery.Thanks everyone
05-02-2010, 10:48 PM
#16
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codes codes came after K & N cleaned and re-oiled.Waited an hour before replacing filter.Bought the car with K & N and everything was perfect.My tech is really stumped that's why even he suggested coming to LS 1 tech and maybe this has been tackled and solved by someone here.
05-04-2010, 05:10 AM
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codes Engine light went out for about a day after I drove her for about 40 minutes and during the run I floored her from a dead stop.Turned her off and restarted with engine light coming back on.Could this still be a leak?Wouldn't an intake leak show itself hot or cold-or can this be an exhaust leak?
