P0175 Fuel System 2/1 Rich

[AAA94]

Hi everyone, Happy 4th (one day late). I recently added Belanger headers and exhaust to the car (driven about 600 miles since install). Everything has seemed to be fine but today when I started the car (after it was heated and parked for about 45 mins) I got a CEL and P0175 code 2/1 Fuel System Rich.

It’s to my understanding that this is the passenger side O2 (upstream) sensor reporting this?

The car is entirely too hot to do anything with at the moment but I came here to have a plan of attack. Check to see if o2 sensors are loose/and wires not damaged? Check air filter/MAF sensor? Any other recommendations?

Should I just clear the code and see if it comes back, or will the code remove itself if the problem is fixed?

 

[AAA94]

Update. I have replaced the spark plugs, I swapped (from pass to drivers) the upstream 02 sensors, I have swapped the MAP sensors (from pass to drivers), and cleared the code each time between. The code keeps coming back. I also noticed rough idle as well as hesitation/jerkiness when shifting to next gear under load. Fuel injector cleaner next? Thanks

 

[Viper Specialty]

Passenger side, upstream sensor.

P0175 indicates that even when the PCM is removing the maximum amount of adaptive allowed fueling, the system is still reading Rich.

Exhaust gasket issues/leaks and o2 sensor heater issues are common with aftermarket headers, as are misfires. However, all of those [except heater issues] result in a LEAN, code, not a rich code.

A rich code is caused by one of three things:

1. legitimately low oxygen content in exhaust, IE, too much fuel. Stuck open/leaky injector would typically be the cause here, but you would likely have other symptoms and its too coincidental. Also can be caused by MAP/MAF mismatches, but thats fairly rare.

2. Melted wiring and wiring crossed with a voltage source, resulting in sensor to read rich no matter what is done.

3. O2 heater not working or not adequate, causing sensor to remain too cool, which will read richer than actual.

#3 is the most common. Could be wiring, dropped sensor, sensor heater ground/supply, or even as simple as sensor location not allowing proper warmup.


This is all spitballing without the car in hand and the ability to run diagnostics directly.

 

[AAA94]

Passenger side, upstream sensor.

P0175 indicates that even when the PCM is removing the maximum amount of adaptive allowed fueling, the system is still reading Rich.

Exhaust gasket issues/leaks and o2 sensor heater issues are common with aftermarket headers, as are misfires. However, all of those [except heater issues] result in a LEAN, code, not a rich code.

A rich code is caused by one of three things:

1. legitimately low oxygen content in exhaust, IE, too much fuel. Stuck open/leaky injector would typically be the cause here, but you would likely have other symptoms and its too coincidental. Also can be caused by MAP/MAF mismatches, but thats fairly rare.

2. Melted wiring and wiring crossed with a voltage source, resulting in sensor to read rich no matter what is done.

3. O2 heater not working or not adequate, causing sensor to remain too cool, which will read richer than actual.

#3 is the most common. Could be wiring, dropped sensor, sensor heater ground/supply, or even as simple as sensor location not allowing proper warmup.


This is all spitballing without the car in hand and the ability to run diagnostics directly.

Thank you for the reply!

So after swapping upstream 02 sensors and map sensors I ran the car and got the same P0175 bank 2/1 code. I cleared it several times and I now got the code on bank 1/1 instead of bank 2/1. However, I plugged the obd meter in and looked at some values and at idle my stft is -8 to -15 on both banks and my ltft is -26% on both banks.

 

[AAA94]

Passenger side, upstream sensor.

P0175 indicates that even when the PCM is removing the maximum amount of adaptive allowed fueling, the system is still reading Rich.

Exhaust gasket issues/leaks and o2 sensor heater issues are common with aftermarket headers, as are misfires. However, all of those [except heater issues] result in a LEAN, code, not a rich code.

A rich code is caused by one of three things:

1. legitimately low oxygen content in exhaust, IE, too much fuel. Stuck open/leaky injector would typically be the cause here, but you would likely have other symptoms and its too coincidental. Also can be caused by MAP/MAF mismatches, but thats fairly rare.

2. Melted wiring and wiring crossed with a voltage source, resulting in sensor to read rich no matter what is done.

3. O2 heater not working or not adequate, causing sensor to remain too cool, which will read richer than actual.

#3 is the most common. Could be wiring, dropped sensor, sensor heater ground/supply, or even as simple as sensor location not allowing proper warmup.


This is all spitballing without the car in hand and the ability to run diagnostics directly.

So I have checked a lot of things since I posted this and still have the same issue. The 02 sensors are both new. Spark plugs are new. I checked fuel pressure and it’s rock solid at 60psi. When I start the car and idle and have the autel live data running, I notice STFT on both banks fluctuating from -5 to -10 and once it’s around 120F to fully heated STFT will get to -12 to -22 on both banks. What’s interesting is that around 130-135F the STFT slowly creep to +values for about 15-20 seconds and then proceed to go back to large negative values again. I should also mention that when the STFTs are negative, the idle is very rough. When they briefly go positive the idle is much smoother. I really have no idea what to check next and why the PCM is commanding such negative trims. Ang help is appreciated.