Hi everyone,
Asking this on behalf of my buddy. He has a 2012 Honda Accord EX-L V6 coupe with 125k miles, is not running right. It Has a check engine light and it's idling extremely high. I hook up my scan tool and it's throwing a P0172 code for running too rich. He says he got new spark plugs, ignition coils, timing belt, and fuel injectors cleaned at a chain shop (I advised him against chain shops but he says that's the only place he can afford to get his car fixed). My first thought is that it's something simple as an air mixer screw being out of adjustment or a gummed up carburetor. Is that his issue? If not, what else could it be?
My first thought is that it's something simple as an air mixer screw being out of adjustment or a gummed up carburetor.
On a 2012 Honda? Carbs have not been used on cars since the early 1990s.
Instead of throwing parts at the problem your friend needs to do some diagnostic work to find the actual cause.
https://www.carparts.com/blog/p0172-code-fuel-system-too-rich-bank-1/
@chucktobias I looked at Live Data and found that LTFT bank 1 -7% of fuel. Could this mean a bad O2 sensor?
The computer is subtracting fuel but it is not extreme. Test the O2 sensor output.
That vehicle may have a wide-band O2 sensor which is much more difficult to test than the old narrow-band type. However you should also test MAF sensor output and check for exhaust leaks upstream from the O2 sensor as suggested in the link.
@chucktobias I did some more testing. MAF is reading 0 volts when you hook up the multimeter everything else is fine per your recommendation. My buddy is looking to save a little money, can he get an aftermarket OEM MAF sensor for like $50 at the auto parts store and it will work fine or should he go with OEM MAF sensor?
What you need to do is check MAF sensor output in live data. At idle showing grams per second it should approximate the engine displacement. Also its output should smoothly increase with throttle position. In fact if that car has an electronic throttle and you graph throttle position against MAF sensor output they should rise in parallel as throttle is increased.
If the MAF sensor tests bad an OEM replacement is preferable by far. An aftermarket knockoff has a high probability of not working properly. You should be able to find discounts on OEM Honda parts online.
@chucktobias MAF Sensor tested bad, per your explanation. I replaced the MAF sensor and the problem was resolved. MAF was the culprit. Thanks for your help!
Good news, thanks for letting us know!