2006 4.6 v8, I have had ignition problems 301 and 305 for a few years Changed a few coils and plugs and no long term fix. Couple weeks ago I got code 172 - #1 bank rich .. I decided to pull all the injectors and clean them. Used a syringe to build up pressure on each injector and a 6 v battery to open it electrically. Squirted carb cleaner thru each. No real pluggage, but very fine contamination came out. Now they all have similar spray patterns and not leaks...... Also noted some dust come out of #1 injector elect plug when I pulled it off so I spray and dryed each injector plug male and female.. all clean. #1 bottom o-ring on injector had failure -- replaced all 16 O-rings.

Put everything back together and ran 15 miles one day, 50 miles today.. light comes on as I pull into the driveway.. Check and it is code 172- fuel rich on #1 bank.. no misfire..... Cleared the code and ran another 20 miles. No misfire, no code yet. Below is the info my scanner recorded when it stored the 172 code.. Fuel trim shows excessive rich on #1 bank.. Any other info from this ? I don't know what to look for in the data. Going by the 670 RPM engine speed and no ground speed, this happened as I stopped in the driveway ?

freeze frame data
fuel system 1 CL
fuel system 2 NA
load % 52%
ECT deg C 87
STFT B1 -14.8 %
LTFT B1 -25.8
STFT B2 -4.7
LTFT B2 -3.1
MAP 50
RPM 670
speed MPH 0
spark adv 8
IAT deg C 36
MAF 7.4
TPS 14.1%
OS2 B1 .7
STFT B1 S1 -14 %
O@S B1 S2 .73
STFT B1 S2 99.2%
O2S B2 S1 .76
STFT B2 S1 -4.7%
O2S B2 S2 .2
STFT B2 S2 99.2%
FP 278 kPa
command EGR 0
command EVAP 0
fuel level % 24
CAT Te 11 672 deg C
CAT T2 21 672
MIS enabled NO
Fuel enabled YES

 

Everything appears to point to one or more injectors, in spite of your efforts.
I would swap injectors, one at a time, between the banks, until the problem show up on bank 2.
If the problem goes to bank 2 and stays on bank 1 as well, you know you have more than one bad injector.
If it never moves over to bank 2 then I'd suspect the computer.

 

@wrvond is correct ----- AND I POSTED MIS-INFORMATION AWHILE AGO --@--> https://www.ford-trucks.com/forums/1...l#post16348254


P0172 and P0175 (Bank1 / Bank2 too rich) is one of those codes that challanges logic and seems to be backwards. Thank goodness for @wrvond and the ability to edit Posts. And I'm going to go back and do just that!


I realized after studying your freeze frame data that I had it backwards! Negative Fuel trims indicates the PCM is trying to 'choke off some fuel' (by shortening injector pulse width) to keep its fuel/air mixture optimum. A VACUUM LEAK will produce the exact OPPOSITE results - very positive fuel trims!


SORRY for my momentary lapse into ignorance!


The "attached pages: from the OBDII Theory of Operation manual snapped me out of it.


The reason for the P0172 is right at the bottom of the second page. LTFT < 25% and STFT <10% -- and both of those conditions are met in your Freeze Frame Data. Everything else looks fairly normal to me.

 

well that's what I wanted to know.. I knew the LT -25% and ST -14% were not good and set the code. I was wondering if anything else in the system might lead someone to believe it was caused by something other than an injector.......... I guess not... In testing the injectors with a pump and 6 v battery they all work, but I guess you cant see a 10- 20% difference in flow...... since it is TRIM down I would think that means one is leaking excess.. I had no leakage. To get EXCESS I would think the injector holes need to be oversize, or solenoid is stuck open... I don't have that.

I guess I will continue to monitor for the light to come back.. Don't know if my meter will read real time or not... would be nice to know if it constantly has the LT fuel excess or it just happens for a few seconds now and then.

 

Injectors are a bummer to diagnose since trim is common to four of them. A misfiring cylinder doesn't even tell you much. Could be the injector on the misfiring cyl that has the leaky one, or it could be because that cylinder misfiring is running TOO lean due to shortened injector pulse width. You might have to take a careful look at plug tips on bank1 to see if you can determine lean / rich ones.


Or like @wrvond suggested - swap injectors bank1 to bank2 (one or two at a time), but in an orderly fashion, while watching for the rich condition or fuel trims to migrate to bank2. I think one thing I would recommend is make sure there are no misfires (Check Mode $06 data for misfire count during the last 10 drive cycles). If there are any - you might do all the typical things to insure good sound ignition.


One other thing I know from personal experience - watch out for sporadic intermittent 'misfires'. I had a flaky COP connector, and when it would misfire because of a rough road or rail road track - I was shocked how quick it would drive STFT negative, and how quickly STFT would migrate into LTFT. Then how long it took for the condition to work itself out and return to normal without doing a battery reset and relearn.


Your Freeze Frame data confirms the Code was set when stopped - at idle. Fuel status was in closed loop, MPH 0, RPM 670, Throttle Position 14%, spark advance 8º, EGR valve closed, Fuel Rail Pressure 278 kPa [40.32 lbs], Mass Air Flow 7.4 grams per second). This was at the END of a drive cycle as the CATs were well warmed up 672º C [1241.6º F]. **Interesting that BOTH Cats are running the same temperature. And catalyst efficiency monitor test indicates both cats are operating at 99.2%. That tells me that at THIS point - the PCM is still able to compensate for the excess fuel in the intake. But it is at its MAXIMUM compensation adjustment (LT 25% & ST 10%). If it gets any worse - it would lead to a P0420 Code (Catalyst below efficiency threshold).

Engine might run a little more efficiently if coolant @ 87º C [188.6º F] ran a little higher with intake air temp @ 36 C [96.8 F]- but doubt that has anything to do with the problem at hand.


Hope this helps, and makes up for my bum advice in that other post! LOL

 

Well I was having a similar problem. At startup I would get a little smoke out of the tailpipe. At first I thought it was just the Chicago winter and condensation. but after the warm weather got here it was different. Let me digress to another symptom of the bad injector. I was driving around town and noticed a distinctly lower oil pressure than normal(I have an aftermarket gauge installed). I was due an oil change so when I got home I changed the oil. It came out like water when cold. I run 5w-30 semi-syn. I thought this was odd. It didn't look milky like coolant and after the change all oil pressures were normal. I ran the test to check for combustion gas in the coolant which came up negative. I drove for about another 1500 miles and the symptoms happened again. I did some research online and found that the injectors may not be closing all the way at shut down and may be flooding the cylinder, leaking past the rings and diluting the oil. I changed all 8 injectors with Ford OEM at a cost of $314.00 from Summit Racing. Next I pulled the plugs to check their condition. #1 was wet and tan all others were tan meaning normal combustion except for #1. I dropped an inspection camera into all the cylinders and only #1 was wet. After the injector swap out and an oil change the truck ran much better but now sounds like a diesel. I think the diluted oil lunched the left side cam phaser and some lash adjusters. GRRRRR, this is after a complete timing replacement including phasers. Believe it or not the Rt. phaser is quiet and the Lt one is making the tell tale tick. I replaced a 8 injectors because I believe that when one goes the others are not far behind and I do not like doing the same job twice when avoidable. I you are thinking about changing 1 or 2 injectors, replace them all and you wil; not be sorry.

 

Injectors don't wear out at a given time.. I have had 3 different trucks with up to 250,000 miles and all ORIGINAL injectors.. If you get a leaking injector, then it should be changed out. Only thing that would justify changing out all injectors is if you know you are using bad gas, water in the gas, heavy contamination, etc... We have 10% ethanol in Illinois and it does a continuous cleaning of all injectors... and MOST last indefinitely.

 

I drove the truck about 100 miles this weekend. Did not get a code for P0172- excess fuel. I checked and the code is stored as occurring once, but will not light until it occurs twice. The stored code again happened at 670 rpm, and 0 MPH --- setting in the driveway.
--- I have noticed if I increase idle speed to 700- 720 with foot feed, the truck seems to run a lot smoother. I get a slight rough idle at 670 rpm.
---I also noticed that in 90 degree weather, the truck has to crank ( cold) for 3 seconds before it starts up... My 2002 and EXP both start as the motor rolls over ONCE.
---I also noticed when the motor is HOT and you restart, it takes 4-5 seconds to startup.. Almost like the "choke" is closed ( related to an older vehicle)..again, I assume this is related to excess fuel.
---I put 2.5 gallons of E85 gas into the tank with 18 gallons of E10 gas. Will let the daughter run that for a month and see if anything cleans up, or still has the code.
---Since I only get the "excess fuel" on #1 bank, I guess that means injector problem, and not related to air flow sensors or other ?
---as I said before, I cleaned all injectors and popped them and had no leakers that I could tell...... will continue to monitor.

 

@steve(ill) , From your freeze frame data and symptoms it is sounding like an injector issue to me. I'm as far as anyone can get from 'expert' and my 'experience' is completely confined to that of my own, but FWIW I have developed doubts about the last four words of the above quote.

I had a rough/ragged idle (like SO MANY forum members report) and unbalanced fuel trims as you also mention. I tried to gather additional knowledge about injectors in one of the only two threads I've ever started: https://www.ford-trucks.com/forums/1...l#post15852658 , but finally decided to bite the bullet and replace all eight injectors as part of my overall phaser job. I finally sprung for the highest quality, new injectors I felt I could find - at $92.00 a pop. I can surely attest that I have never regretted it for one second right from the first startup. The idle and silence is phenomenal.

My reasoning was: I calculated that, at 212,000 miles, the injectors have each opened and closed approximately 125 to 150 million times - and had around 2,280 gallons of (sometimes cheap) gas pumped through each one of them !!! Yeeks. And NO ONE knows how many times the engine had cooled (allowing the gas on the tips to evaporate away completely - leaving behind hard residue/deposits). Then to expect each one to remain in calibration, and deliver preciously the right amount of fuel on a 'common', and very short injector pulse widths for all four cylinders on that bank! That's asking a lot from ANY component.


I know they are expensive. Good (non refurbished ones) are damned expensive. But I also think @flyguy108 is right:
Plus, individual injectors are difficult to diagnose. ?? Inspect plug tips for (subtle at best) lean / rich indications / swap bank 1 injectors to bank 2 and see if P0172 moves. ??? Not sure what else would be informative.


You do not mention if you did a 'battery reset & relearn' after the work in post #1. And there is no way to know at what RPM the ECU switches to the idle fuel trim table entry, but 670 RPM (or there-abouts) would seem about right. At that RPM and MAF flow rate, injector function would probably be at about the most 'critical' point of operating conditions. You do mention (as do SO MANY forum members) ragged idle unless you increase R's a little bit.


JMO. I won't blame you if you take it with a grain of salt though, after I was so wrong in my first post on this issue.... LOL


Anyhow - as always I wish only Good luck

 

F150 , I think there is a lot of truth in what you say. My point was I have a couple 5.4 motors with 250K miles and have the original injectors and no problems on the motors............. on the other hand this 4.6 has 135K miles and has had "something" wrong with it for 2-3 years... I think its ONE injector, but I do see the rational in putting in a set and being done with it forever ( if that is the problem and it sure appears to be).... I thought I had done a good job of cleaning them inside and out with the carb cleaner, but your only doing a visual spray pattern and that is very subjective at best.......... It does seem like a dumb idea to switch the injectors around 3-4 times to narrow it down.. Getting them out once was a PITA.. but I think that was due to hard stuck O-rings... might be easier the second time around.
I have not heard back from the kids yet... If the truck continues to have problems after running a tank or two of high ethanol gas thru them, then im probably doing the injectors later this summer or early fall.