Hi there. Need some help. Getting a P0172 only, no other codes. Tks

Hi, pleasure joining the forum. I´d appreciate some help from such experienced people here. I am getting a code P0172 only, no 0175 or any other code. I am thinking this would not be related to a MAF or O2 sensors since it is only affecting bank 1. Any ideas? Tks!

System too Rich (Bank 1)

P0172 System too Rich (Bank 1)
Are you using propane, ethanol or gasoline for fuel there in Paraguay?

Normally the SOHC V6 has lean codes instead of rich codes.

P0172 only, no other codes

Hi,

I normally use ethanol since this is a flex fuel engine, but right now it is running good unleaded fuel (95 octanes). Any thoughts?

Tks!

leaking injector?

I can't think of many sources for a too rich condition on just one bank. One might be a leaking fuel injector. Ethanol is hard on seals although your flex engine is designed for it. Another might be a defective O2 sensor - there actually is no rich condition. Have you replaced anything recently?

Haven't replaced anything yet. Shouldn't the O2 sensor trigger a code of its own? I have a snap on of the readings when the code goes active. Anything in particular I should look for to pint point the failure?
Tks

pids

I would start by checking the long and short term fuel trims for both banks.

Hi, finally got the specs of the snap shot when the FC triggered. Please let me know if you see anything that calls your attention. By the way, FC P0175 was also logged, which is system too rich (Bank 2). So now we technically have rich combustion on both banks.

Load PCT 60,8%
Shrt FT1 -3,1%
Long FT1 -25%
Shrt FT2 3,1%
Long FT2 -23,4%
MAP (KPA) 62
RPM 1502
MAF (G/S) 22,61
O2 B1S1 0,765 V.
O2 B1S2 0,635 V.
O2 B3S1 0,050 V.
O2 B3S2 0,665 V.
Shrt FT B1S1 -1,6%
Shrt FT B3S1 1,6%
BARO (KPA) 101

There are other readings but I believe these are the ones that could help us find whats wrong.

Tks!!

engine load?

What were the circumstances for the posted values? Was the vehicle accelerating or climbing a hill or was the transmission in Park?

60% load and 22.6 gm/sec seems excessive for 1500 rpm. Is the stock MAF sensor installed?

It was under cruising. Since I bought the vehicle from second hand, I am not sure the MAF is stock. Should I try cleaning the MAF sensor?

clean the MAF sensor

If the MAF sensor diameter is smaller than stock the readings will be higher than normal and the air/fuel ratio will be rich. I suggest spraying the sensor element with MAF sensor cleaner or alternatively electronic equipment aerosol. The element is fragile so don't touch it with any tool.

engine coolant temperature?

Read the engine coolant temperature that is sent to the PCM. If the reading is cold when the engine is warm the PCM will unnecessarily richen the air/fuel ratio.

53 Celcius. It would be 126 F

engine warmed up?

What is the thermostat setting? Did the engine have time to reach the thermostat setting? If so, then I suspect your rich problem is mainly due to a faulty engine coolant temperature sensor.

how can I check the Tstat setting or find out if it had time to reach its setting temp?
A erased the codes a couple of times and the light seems to comes on during light acceleration. This last time I deleted the codes, just P0172 came back on. It seems to be an intermittent problem

watch the temperature gauge

Do you have the SOHC V6 engine?
The typical thermostat setting is about 85 degrees C. Watch the engine temperature gauge on the instrument cluster when you cold start the engine. After driving for 10 minutes or so the reading should change from cold to about mid range and then not change. That indicates the thermostat is working and the engine coolant is at the thermostat setting. Then log the engine coolant temperature (a different sensor) and it should be about 85 deg C.

I can do the first part but unfortunately my scanner does not show live readings, only snap shot of a triggered FC. Still, I'll check how the gauge behaves and get back to you. Tks a lot!

disconnect the IAC valve connector

Drive the vehicle until the engine warms up, leave it running and open the hood, then disconnect something easy that triggers a DTC: IAC valve electrical connector, MAF sensor electrical connector.

Got it. I'll do that

Reporting back.. Removed the MAF sensor, cleaned it well, installed it back and the truck ran well for a little over a week. No CEL came on. Today, out of nowhere, CEL came back on. FC 0193 by itself (fuel pressure sensor high input). Don't have the tools the check the fuel pressure. Any ideas? Tks!

fuel pressure sensor

There is a fuel pressure sensor on the fuel rail that provides the PCM with the fuel pressure reading. Here's where it is on a 2005:

This is what it looks like:


Make sure the electrical connector has not come loose and that the vacuum hose is in good condition and connected.