Bigrome34

I have a 99 Si and I have a CEL on. I started out with 4 and now I am down to this last one. The code on the scanner is P0172 fuel system too rich... I have already changed the fuel filter to no avail. What could be another solution?

SeanK325

from obd-codes.com

Possible solutions include:

- Inspect all vacuum and PCV hoses, replace if necessary
- Clean the MAF sensor. Consult your service manual for it's location if you need help.
- Inspect fuel lines for cracks, leaks, or pinches
- Check the fuel pressure at the fuel rail
- Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
- Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

Bigrome34

would that be a maf sensor or a map sensor???

Sr420Det

Your honda uses a map sensor help tell how much air is entering the motor. How do your plugs look?

Bigrome34

spark plugs???

Sr420Det

yeah the spark plugs, do they look overly rich to you?

Former User

Measure the fuel pressure and check whether the fuel pressure regulator is working.

Also check for a stuck open fuel injector.

Bigrome34

spark plugs have a little bit of oil on them

Bigrome34

how do i check fuel pressure and wether the FPR is working or not? how would i check for an open fuel injector?

honda-992

yea if i were you i would check all vacuum hoses because it sounds like a vacuum leak..or a small crack before the first o2 sensor..on my 97 civic i had a tiny exhaust crack before the o2 sensor and it threw a cel for fuel mixture

Former User

See diagram and check for fuel flooded cylinders.

Bigrome34

well i know for sure that my headers have a leak in them...they are scraped on the bottom side...could that be the problem?

ron, i will try the test out and see if that works

Former User

An exhaust leak near or upstream of the primary O2 sensor would make the engine run rich.