I have a 2004 Acura MDX that continues to throw a P0175 code. It has about 87,000 miles. Headgaskets were just replaced and all the valves were adjusted. Vehicle runs great at idle and under load. After it sits at idle for a while it will give a P0175 fuel trim bank 2, system too rich. There are no air leaks that I can find. The EGR valve is clean. The fuel pressure is about 64psi. Any ideas would be a great help. Thanks in advance!

Wednesday,15,February,2012
Freeze Frame Data for address 09
PID02 DTC that caused freeze frame data storage: P0175
PID03 Fuel system 1/2 status: Closed loop, using O2 sensors
... Closed loop, using O2 sensors
PID04 Calculated load value: 36.5 %
PID05 Engine coolant temperature: 86 °C
PID06 Short Term Trim - Bank 1: 0.0 %
PID07 Long Term Trim - Bank 1: -1.6 %
PID08 Short Term Trim - Bank 2: -16.4 %
PID09 Long Term Trim - Bank 2: -16.4 %
PID11 Intake Manifold Absolute Pressure: 36 kPa abs
PID12 Engine RPM: 726 /min
PID13 Vehicle speed: 0 km/h
PID14 Ignition timing advance for cyl #1: 10.5 Degrees
PID15 Intake air temperature: 71 °C
PID17 Throttle position sensor: 14.1 %

Monday,27,February,2012
06:Short Term Trim - Bank 1 2.3 %
07:Long Term Trim - Bank 1 -2.3 %
08:Short Term Trim - Bank 2 -0.8 %
09:Long Term Trim - Bank 2 -3.9 %

Monday,27,February,2012
06:Short Term Trim - Bank 1 1.6 %
07:Long Term Trim - Bank 1 -5.5 %
08:Short Term Trim - Bank 2 -1.6 %
09:Long Term Trim - Bank 2 -7.0 %

 

Swapped in good known B2 S2 O2. Smoke tested and found no leaks. Swapped in good known EGR valve and coolant temperaure sensor. Also swapped coils across banks. Performed fuel injection cleaning and still get the same result when it stays running at idle. Going to recheck the valve adjustment on bank 2 and perhaps swap the injectors across banks.

 

could be one of the injectors on bank 2, what is the reading of the map sensor? how do the spark plugs look on bank 2.

 

-vacuum leak
-exhaust leak before the first sensor (unlikely but, maybe)
-fuel pressure (already checked)
-fuel injectors

Also, I saw this code pop up on my friends Tahoe and it turned out to be a restricted exhaust (bad cat)

 

Have your valves adjusted. I adjusted the 05 Odyssey EX at 75,000 and every single exhaust valve was too tight.

Check your valve clearances at 50K miles (or less) and not 105K as Honda recommends.

 

Check the map voltage, the car has three wires at the sensor. bat voltage ground and ref voltage. Ref voltage should be at .85v to .90v. From .95v to 1.05 will throw a rich code. 1.05 and higher will throw a misfire code. Plus the fuel injectors like to leak down on that vehicle

 

Adjusting the valves is what changes the map voltage higher and lower. The tighter the valve the higher the map ref voltage reading.