mavrik2747

I've had the P0172 code for awhile, and figured it was due to my Bank 1 Sensor 1 o2 sensor being out. Last weekend I replaced the o2 sensor and the passenger side cat.

Now I'm still getting the P0172 code. My o2 sensor is working and runs fine. Yesterday I was looking at the fuel trim levels in my Torque Pro app. My long term fuel trim on bank 1 looks like where the issue is.

When accelerating, the LTFT1 runs between -7 to -13%, but when I let of the gas and just idle, it jumps to -27 to -33%. From everything I've read, the range that the trims should be in is +20 to -20%, so clearly it's running out of range. The weird thing though is that the short term fuel trim levels run in the normal range.

Anyone with any advise or ideas on what the problem could be? I'm assuming it's the fuel injectors, but would it be all 4 on bank 1? I have no idea how it could affect the long term fuel trims but not the short term.

F150Torqued

Possibly could be a fuel injector. BUT, you have a marvelous tool in the Torque App for sorting things out before throwing expensive parts at it. You did not mention what bank 2 is doing, but fuel trims (both short & long) going very negative on 'decell' is normal.


However, Just a few 'intermittent' misfires will produce the exact symptom you describe, and is a common issue on our 5.4L's. Each misfire pushes all that unburned fuel into the exhaust and swamps the O2 sensor on that bank. The PCM's immediate response is to decrease STFT trying to compensate. That STFT fairly quickly propagates into LTFT 'multi-dimensional' table -for the current operating environment (Idle, low rpm, medium rpm, upper rpm at different engine loads). If a FEW misfires are occurring under a given operating environment (RPM/LOAD) - you will see LTFT more and more negative in THAT operating environment. [That's because the ONLY thing that corrects LTFT, in that operating range, is proper STFT in that operating range over an extended period of time.


This WILL happen, 'before' the misfire counts exceeds the EWMA (Exponentially Weighted Moving Average) formula used by the PCM to set a P0300 or P030X code. You may be seeing the 'precursor' to the above misfire codes, or FLASHING CEL, or P0420, or - heaven forbid - cam phaser related issues.


With Torque - look at the FREEZE FRAME report to determine what the operating environment was at the instant the P0172 code was set. Run a Mode $06 diagnostics report ('Test Results' from main screen) and take a look at misfire counts during the last 10 driving cycles. Generally should all be zero or very near zero.


Then, I would suggest doing a battery disconnect reset and a relearn procedure to clear fuel trim tables and codes. Set up a Torque dashboard to monitor short/long trims on both banks together with some other parameters (such as front O2 sensors as in the photo below) and figure out a little more about what is going on under different driving conditions. If the same symptoms reoccur on ONE bank, (or it it is just TIME for new plugs) carefully inspect the plugs for one black / sooty tip like it is running rich. I was able to locate and replace the exact single bad injector on my wife's car with this procedure.







Good luck and happy Torqueing

mavrik2747

Man thanks for all the good info!

I got the torque app to monitor misfires as I have the dreaded shudder at 45-55 mph even after I put in new plugs about 2 months ago.

This morning I had 3 misfires from cylinder 3, 1 at start up and 2 random ones during normal driving, NOT during any time it shuddered. But I've also had misfires on cylinder 1, 5, 6 and 7 before, which most occur during start up. (I don't get any misfires when it shudders, so I'm stumped on that issue for now)

I do have my torque app set up to view both long term and short term fuel trims, and right next to the o2 sensor data. STFT is usually between 10 to -10%, it's only the LTFT1 that has the high reading.

I'll try the battery relearn process tonight and see what that does, since I didn't do it after I replaced the bad o2 sensor and my passenger side cats.

F150Torqued

I note you said you got Torque Pro to "MONITOR" misfires. I may have mistook your meaning, but a small word of *caution* that might save you some effort ----. I know Torque Pro has selections for Misfire Count for each cylinder with the "FORD ENHANCED PIDs". That MAY WORK on some vehicle models / configurations, but it does NOT on my 2004, 5.4L 2wd Lariat. My (extensive) "hacking" efforts on the OBDII system reveals Torque is using PID #'s $160E thru $1615 for misfire counts on cyl 1-8 respectively. Those specific PIDS may work on Ford Ranger or Ford Focus or some models, but do not respond on my 5.4. { The MODE $06 "Test Results", however, does show the count for each cylinder - current drive cycle and last ten drive cycles, but can't be used to "MONITOR" live data. }


I took a look at some of your recent postings and note you have recently changed spark plugs and are still experiencing the 45-55 mph shudder. Did you have spark plugs break on removal? If so, you have (fortunately - or unfortunately, depending on how you look at it) ran into someone who has a rather unusual theory about that based on personal experience with fixing it. And it is NOT the torque converter. It is Misfires!


An extensive write up about it is here: Theory on Random Misfire (45-55 mph shudder)
http://www.f150online.com/forums/v8-...ml#post5159499
Also, some reasoning behind the theory is here: Heat Range
http://www.f150online.com/forums/v8-...ml#post5161039
As always, I hope this helps.

mavrik2747

I didn't have any plugs break on me, but a few of them had some serious carbon build up. The latest effort I've been working on is replacing the COPs. They had a cheap aftermarket COPs on them and I just got soem OEM COPs to put back on.

Thanks for all the great info, good to know about the Torque App. During the drive I use Real time info to monitor misfires...the misfires that I do get show up on the total count, but don't show up on the individual cylinder misfire monitors. When I do get a misfire, then I go into the test results to see which cylinder the misfire was on. Not sure of which mode it is, but it's down towards the bottom of all the modes where it lists misfire info 3 different ways for for cylinder. This is where the misfire information will match up to the live data misfire counts I get.

But again I still don't get misfires during the shudder, I'll take a look at mode $06 on my way home after work.

As for the p0172 code, last night I did the battery relearn process. The LTFT1 still gets up to -25% or so, but not up to 30 on up. The p0172 code hasn't come back yet, so hopefully it corrected itself. If the code pops again I'll take a look at the freeze frame report and see what comes up.

Now just need some time to be able to start pulling plugs again to check 'em, never enough time in the day! Thanks again for the help.

mavrik2747

Here's the freeze frame log

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 17.647 %
Engine Coolant Temperature = 186.8 °F
Fuel Trim Bank 1 Short Term = -15.625 %
Fuel Trim Bank 1 Long Term = -27.344 %
Fuel Trim Bank 2 Short Term = -0.781 %
Fuel Trim Bank 2 Long Term = -10.938 %
Engine RPM = 1,312.5 rpm
Speed (OBD) = 34.797 mph
Timing Advance = 25 °
Intake Air Temperature = 75.2 °F
Mass Air Flow Rate = 9.29 g/s
Throttle Position(Manifold) = 14.118 %
Fuel trim bank 1 sensor 1 = -15.625 %
Fuel trim bank 2 sensor 1 = 0 %
Fuel Rail Pressure (relative to manifold vacuum) = 37.778 psi
Voltage (Control Module) = 13.94 V
Relative Throttle Position = 2.353 %

mavrik2747

I ran the Mode $06 test, got test incomplete or dependent test failed on each one, so don't know what that is supposed to mean.

Test report:
------------------
MID:$01 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Test incomplete or dependant test failed
--
MID:$01 TID:$80
- O2 Bank 1 Sensor 1
Test incomplete or dependant test failed
--
MID:$01 TID:$81
- O2 Bank 1 Sensor 1
Test incomplete or dependant test failed
--
MID:$02 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$02 TID:$81
- O2 Bank 1 Sensor 2
Test incomplete or dependant test failed
--
MID:$03 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 3
Test incomplete or dependant test failed
--
MID:$03 TID:$81
- O2 Bank 1 Sensor 3
Test incomplete or dependant test failed
--
MID:$05 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 2 Sensor 1
Test incomplete or dependant test failed
--
MID:$05 TID:$80
- O2 Bank 2 Sensor 1
Test incomplete or dependant test failed
--
MID:$05 TID:$81
- O2 Bank 2 Sensor 1
Test incomplete or dependant test failed
--
MID:$06 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 2 Sensor 2
Test incomplete or dependant test failed
--
MID:$06 TID:$81
- O2 Bank 2 Sensor 2
Test incomplete or dependant test failed
--
MID:$07 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 2 Sensor 3
Test incomplete or dependant test failed
--
MID:$07 TID:$81
- O2 Bank 2 Sensor 3
Test incomplete or dependant test failed

F150Torqued

@mavrik2747

Oh my, I have unintentionally misguided you. Do not be 'alarmed' by your Torque Pro diagnostics test results. It's not Torque's fault or your fault - but I should have told you more about the massive amount of stuff going on in the computer on your truck.

I recommended you do a battery reset ---- and then recommended you run a mode 6 test. (JUST NOT BACK TO BACK)!!. We managed to clear everything out on the ECU. Then we had the Torque App ask the ECU for results of OBDII mandated diagnostics tests. That didn't work out too well for us. (shot ourselves in the foot).

There are literally hundreds of diagnostic "Monitoring tests" performed by the PCM continuously. Each is identified by a Monitor ID (MID:$XX), and each monitor is broken down into individual "Tests", identified by Test ID (TID:$XX). The "results" or "completion ID" of these various tests are what ultimately lead to DTC codes being set if the "completion ID" is outside factory determined parameters.

Each of these tests require a certain set of 'conditions' to be met before the test can start, or continue, and complete. For example, Catalyst Monitor operation and entry conditions are shown here from the Motorcraft OBDII Theory of Operation Manual.



As you can see from the last table entry, 25-35 mph steady state driving must occur for the test "to complete". Your Torque Mode $06 test was simply done prematurely, and the only thing the PCM was able to report was "test incomplete or dependent test failed". So don't stress over it. IN FACT, mode 6 test "failures" should all be taken in proper context. Remember - Torque reads a snapshot of the current tests that may ultimately _lead_ to a DTC, but in many cases failures have to occur multiple times to set a DTC - and completion ID's filtered through an exponentially weighted moving average (EWMA) before a DTC is set.

This is complex theory, and you didn't ask for OBDII 101. But if you are interested in the technical stuff - it is thoroughly discussed in the Motorcraft OBDII Theory manual. It is INVALUABLE reading. You can download a copy for your truck from this link.

http://www.fordservicecontent.com/fo...t/OBDSM407.pdf

Also, the freeze frame data you provided is most useful when considered with the code that caused the freeze frame record to be taken. Presumably, codes were cleared (and I think freeze frame data, IDK) with a battery disconnect. So I assume a code (or at least a 'grey' code - one that has to occur multiple times before setting the MIL). I am going to assume P0172 - BECAUSE two readings in the freeze frame data MATCH "Rich malfunction" in the bottom table of page 31 of 98 in the above linked OBDII Theory for fuel monitor malfunction thresholds. LONGFT <25% and SHRTFT <10% = rich malfunction. THAT is the trigger conditions for a rich condition on that bank.
It looks to have occurred early in the drive cycle. Engine temp was barely up to temp (186º). Nice day, IAT 75º (under the hood - might have been 65-68 outside). You were lightly decelerating, or at least just coasting along (engine load 17%) at 35mph, probably 2nd gear (1312 rpm), foot barely on the pedal (RTP 2.35%) (TP 14%). Fuel rail pressure @ 37.778 psi is fine for the above load conditions. All looks pretty normal.

I do notice two (non-conclusive - but verifiable) things. The Mass Air Flow Rate of 9.29 grams/sec (at 1312 rpm) strikes me as possibly less than what I //think// might be normal, unless deceleration was more significant than I am gathering. And, Bank 2 is actually reading slightly negative (on the long term side). Just not as much as bank1. Unfortunately, might know it, but the Diagnostics REFERENCE chart (ATTACHED BELOW) gives MAF reference values in Volts - NOT grams/sec. But it is something you can test - and remove / clean without lots of cost. I know MAF effects both banks equally, but other subtleties may exist - such as a few misfires on bank 1 throwing it more into rich territory.

Did you 'inspect' each plug when removing them from bank 1 looking for ANY signs of a rich mixture (black sooty snout on a plug)?

mavrik2747

WOW, that is a ton of information and I definitely learned something new today! Thanks for all the info....

A few things for me to clarify...the freeze frame occurred after I did a battery reset and the P0172 code came back. I've previously cleaned the MAF but I'll do that again. I swapped out the COPs from aftermarket ones to OEM ones this weekend. I only pulled sparkplug from cylinder 1 since I got a lot of misfires from it, picture attached. Only 2 months old, so there is some carbon/soot on it. I put it back in to see if the new COP might make a difference and haven't had a misfire on it yet.

I'm going to pull the rest of the plugs on bank 1 this week when I can get some time. I've had mostly misfires on cylinders 1 and 3, and periodically 2. I occasionally get a misfire on bank 2, but of course that won't contribute a rich condition on bank 1.

mavrik2747

So the P0172 code came back and here's the freeze frame report for it. Also did a screen grab of the live data, you can see the range of the fuel trims on bank 1.

The one thing that's noticeable to me on the freeze frame report is that the LTFT1 % is exactly the same as it was in the first freeze frame report above, and the MAF rate is even lower than the previous one.

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 31.765 %
Engine Coolant Temperature = 170.6 °F
Fuel Trim Bank 1 Short Term = -5.469 %
Fuel Trim Bank 1 Long Term = -27.344 %
Fuel Trim Bank 2 Short Term = -3.125 %
Fuel Trim Bank 2 Long Term = -7.812 %
Engine RPM = 657.25 rpm
Speed (OBD) = 0 mph
Timing Advance = 24.5 °
Intake Air Temperature = 80.6 °F
Mass Air Flow Rate = 8.35 g/s
Throttle Position(Manifold) = 14.902 %
Fuel trim bank 1 sensor 1 = -5.469 %
Fuel trim bank 2 sensor 1 = -3.125 %
Fuel Rail Pressure (relative to manifold vacuum) = 38.628 psi
Voltage (Control Module) = 14.118 V
Relative Throttle Position = 3.137 %