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5.4L F350 Code = P0506

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Old Oct 27, 2009 | 01:11 PM
  #1  
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5.4L F350 Code = P0506

Vehicle Specs:
2005 Ford F-350 XL
SRW
5.4L

I am running into major issues with this truck. I have a few codes throwing out via OBDII: Bank 1 too Lean and Evap System Gross Leakage.

I changed both sensors on Bank 1. Once the sensors were changed out, I started to get a hesitation and idling problems. The RPM would fluctuate and normal idling would be around 470-500 RPM.

I pulled the code today, the Bank 1 lean code is gone, now I have a P0506 ~ Idle Air Controle RPM Lower than Expected. The EVAP Leak showed up also, but have yet to pop back up after erasing it and driving it a few cycles.

Any idea what the PO506 code could be coming from? I wish it was a simple fix, just swapping the IAC valve but the 2005+ have dbw.

Thanks in advance.
 
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Old Oct 27, 2009 | 01:30 PM
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evap system could mean a vacumn leak..have you checked all your hoses? How about the gas cap? Good shape? check the cannister.
 
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Old Oct 27, 2009 | 02:26 PM
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Clean the throttle body. It will most likely fix the p0506. The EVAP leak could be a lot of things.
 
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Old Oct 27, 2009 | 02:30 PM
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The 3V engines (2005+) do not have an IAC. Idle is controlled directly by the PCM through the Throttle Position Sensor (TPS) since it is all throttle-by-wire. It sounds like there is an issue with the TPS and/or the mounts for the sensor are loose since you are having idle and hesitation issues.
 
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Old Oct 27, 2009 | 03:32 PM
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This DTC is set when the powertrain control module (PCM) detects an engine idle speed that is less than the desired RPM.
Possible Causes: Air intake restriction
Exhaust restriction
Engine mechanical fault.
Sludged throttle body
Damaged electronic throttle body (ETB)
Damaged PCM

Some 2004-2006 4.6L and 5.4L F-150 (excluding F-150 Heritage), 2006 5.4L Mark LT, 2005-2006 6.8L E-350 / E-450, 2005-2006 6.8L F-Super Duty (F-250 to F-550), 2006 6.8L F-53 Motorhome Chassis, 2006-2007 4.0L Explorer 4 dr, 2007 4.0L Explorer Sport Trac, 2006-2007 4.0L Mountaineer, 2006 4.0L Mustang, 2006 - 2007 4.6L 3V Explorer / Explorer Sport Trac / Mountaineer, 2006 4.6L 3V Mustang, and 2005-2007 Crown Vic / Grand Marquis / Towncar vehicles may exhibit one or more of the following symptoms: drive-away hesitation, loss of RPM on deceleration, difficulty starting, and/or idle RPM less than desired. Malfunction indicator lamp (MIL) may be illuminated with diagnostic trouble codes (DTCs) P0506 and/or P0505. These conditions may appear after battery disconnect, dead battery condition, or keep alive memory (KAM) reset. The symptoms may be due to engine deposits in the throttle leading to airflow less than desired.

These are copy and pasted from Ford service publications. Clean the throttle body, It should fix the p0506 and the idling problems you have.
 
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Old Oct 27, 2009 | 07:16 PM
  #6  
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The P0506 code is now gone, I spoke too soon. I ended up removing the throttlebody and noticed alot of gunk. I cleaned it up with some carb spray, threw it back on and now the idling and code is gone.

But! Now I am getting back a lean code. P0171; bank one too lean. I thought the replaced o2 took care of it but right after the cleaning the throttle and driving the truck for about 30 miles, P0171 came up. But as of right now, it's just pending.

Just to give you an idea of how the engine is running; at low rpm >1200 I have a very noticed ticking/knocking noise. Kinda like a diesel idling. It does sound like it is on bank one also. I have already replaced all the spark plugs, still get the noise.

The EVAP code hasn't popped back up, but it's in a non ready state right now so it may come back .

Thanks for the help fellas.
 
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Old Oct 27, 2009 | 07:51 PM
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The ticking/knocking noise may be the cam phaser on the bank 1 side. We replace lots of cam phasers. It should not cause the p0171 code. Most of the time p0171 or p0174 are caused by a vacuum leak. Do you have a way to check the short and long fuel trims ? 2005 5.4 3v had lots of problems with the fuel injectors sticking ( open and closed). Does your truck idle smooth or does it seem to have a miss at idle.
 
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Old Oct 27, 2009 | 07:57 PM
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My guess would be a leak at the PCV valve grommet, PCV valve elbow, or IAC elbow. You may also try to clean the MAF with a proper cleaner designed for it.
 
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Old Oct 27, 2009 | 11:39 PM
  #9  
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Originally Posted by Darrenigel
The ticking/knocking noise may be the cam phaser on the bank 1 side. We replace lots of cam phasers. It should not cause the p0171 code. Most of the time p0171 or p0174 are caused by a vacuum leak. Do you have a way to check the short and long fuel trims ? 2005 5.4 3v had lots of problems with the fuel injectors sticking ( open and closed). Does your truck idle smooth or does it seem to have a miss at idle.
Here's a freeze frame reading I picked up for the PO171 code

Calc Load (%)---------------80.3
ECT (F*)--------------------194
STFT B1 (%)-----------------3.9
LTFT B1(%)-----------------20.3
STFT B2 (%)----------------1.5
LTFT B2 (%)----------------11.7
ENG RPM ------------------2613
Veh Speed-------------------21
Spark Adv ------------------11
o2S B1 S1 ------------------0.355v
STFT B1 S1 --------------(-)6.2%
o2S B1 S2 ---------------0.605v
o2S B2 S1---------------0.300v
STFT B2 S1 ------------0.7%
o2s B2 S2 ---------------0.720v

I wish I knew what all those numbers meant, I hope you can decipher those numbers and help a lost soul out.

I did suspect a faulty injector since it is a lean condition, just on one bank.

As for idle, it does get a few miss here and there. But it's not a consistent miss.

khgmai,

I have tried to dig around of leaks but I can't find anything. I have doused areas with starter fluid. If there were leakage, the engine rpm would fluctuated but it doesnt.
 
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Old Oct 28, 2009 | 08:12 AM
  #10  
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This is my best educated guess with the information I have. With the engine rpm @2613 rpm's, vehicle speed @21 mph and the load 80% I'm going to assume you were accelerating when the code was set. The truck is running lean on both banks but the bank 2 is not over the thresh hold to set a p0174 ( ltft b2 would have to be 20% or higher to set bank 2 code). When a p0171 or p0174 are set on acceleration it eliminates a vacuum leak as the vacuum is low on accel. I would suspect a fuel delivery issue like a restricted fuel filter or a fuel pump going out. I would check the fuel presure and the fuel volume. The spec for fuel presure is wide ( 35-70 psi). I would expect it to be around the high 40's to low 50's. If you have a way to test it while driving make sure the presure does not go down while accelerating. If it does go down on accel that is a problem. The fuel is delivered to the bank 2 fuel rail first and then runs through the cross over to the bank 1 side, so bank 1 is the last to get fuel. I hope this helps out. If I think of anything else I will post it later.
 
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Old Oct 28, 2009 | 09:07 AM
  #11  
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Thanks Darren...The code did throw out while driving, I had the scanner hooked up during my 20 mile hike.

The freeze frame also gave me FP ~ 38.7 PSI and fuel level of 72.9%. I am assuming the FP reading is coming from the OEM fuel pressure sensor on bank 2 side. So it does seem like I am on the lower side of the range you have posted.

I actually have already replaced the Fuel Filter 2 weeks ago. I am hoping it's not a fuel pump since they are big bucks but what puts the fear in me is the fact that I have run the tank dry a few times.
 
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Old Oct 31, 2009 | 12:29 AM
  #12  
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On the back of the intake there is a rubber tube. Drivers side at the firewall under the fuel rails. It is buried back there. With engine at idle spray some intake cleaner along the back of the engine almost like your trying to hit the front top of the bell houseing. See if the idle changes. Also Ford has a recall on this tube. Its a rubber elbow that goes from the metal booster tube to the lower Left rear of the intake intake. A small leak there will cause idle concerns and lean codes. A big leak or break will cause a stall and loss of power brakes.
 
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Old Nov 5, 2009 | 10:52 AM
  #13  
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Thanks blade, I will check it out. This truck has become a nightmare on all level.

The evap gross leak code is back. I know there's a TSB on the charcoal canister. I wished I had addressed the issue while the car still had the factory warranty. I have always had the fueling issue, 8 months after purchasing the truck, but always thought it was the gas station's vapor recovery system.
 
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