W203 P0172 but Fuel Trims Rich?
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2003 C230
W203 P0172 but Fuel Trims Rich?
Hi,
I recently picked up a C230. Of course, just after I bought it the MIL illuminated with what seems to be a common problem P0172. The part that's confusing me is the Long Term Fuel Trim is pegged at +23 @ idle, less during accel. If the system is too rich, wouldn't the computer be trying to pull all the fuel it can resulting in negative LTFT? It doesn't make sense to me that it's complaining of rich mixture when it's adding 23% fuel. Car runs and drives fine and the indicated fuel economy seems OK @ around 8L/100km [haven't had a chance to directly measure it yet]
Can anyone help me understand what's going on here, I'd really appreciate it!
I recently picked up a C230. Of course, just after I bought it the MIL illuminated with what seems to be a common problem P0172. The part that's confusing me is the Long Term Fuel Trim is pegged at +23 @ idle, less during accel. If the system is too rich, wouldn't the computer be trying to pull all the fuel it can resulting in negative LTFT? It doesn't make sense to me that it's complaining of rich mixture when it's adding 23% fuel. Car runs and drives fine and the indicated fuel economy seems OK @ around 8L/100km [haven't had a chance to directly measure it yet]
Can anyone help me understand what's going on here, I'd really appreciate it!
