Cel p0172

[freeon]

What causes CEL P0172 System Too Rich, Rear Bank (Bank 1)?

 

[docjohn]

http://www.nsxprime.com/forum/showthread.php/75525-Help-with-CEL-codes?highlight=p0172

 

[Old Guy]

So many possible causes. Presumably you have an OBDII code reader. Connect it up and watch the long and short term fuel trims. If the fuel trims are running big negative numbers on the back and closer to zero on the front then you have a problem exclusive to the back cylinders. If both front and back fuel trims are running big negative numbers then the problem is with both banks and you may just have exceeded the error threshold on the back cylinders first.

If the fuel trims are big on just the back, I would start with checking for a leaking fuel injector (s) on the rear bank. If the fuel trims are big on the front and back then the fuel pressure could be out of spec. There are other causes; but, I would start with the injectors and fuel pressure.

 

[freeon]

So many possible causes. Presumably you have an OBDII code reader. Connect it up and watch the long and short term fuel trims. If the fuel trims are running big negative numbers on the back and closer to zero on the front then you have a problem exclusive to the back cylinders. If both front and back fuel trims are running big negative numbers then the problem is with both banks and you may just have exceeded the error threshold on the back cylinders first.

If the fuel trims are big on just the back, I would start with checking for a leaking fuel injector (s) on the rear bank. If the fuel trims are big on the front and back then the fuel pressure could be out of spec. There are other causes; but, I would start with the injectors and fuel pressure.

My OBDII code reader is cheap one that I only used to read and clear codes. I'll check over the weekend to see if I can use to monitor. One thing I forgot to mention is that it always comes on when in slow traffic. Not sure if that points to a certain thing.