2000 Expedition 5.4 4x4 P0171 & P0174

[Mr67Stang]

I think I got these codes right, but they equate to Lean on banks one and two. Eventually, I get the codes for Bank 1 & 2 Oxygen sensors lack of switching indicating lean condition. When I start this truck up it revs to 2200 rpm and takes a bit to come down. I have done the basics as far as replacing the PCV hose, elbow etx. I have sprayed no less than three cans of carburetor cleaner all over this intake with no results. My LTFT is pegged at 25% at idle and about 0%-8% at 55 mph. Yes, I have a live data scanner. This of course indicates vacuum leak. I have isolated every vacuum port one at a time blocking it off to see if anything makes a difference. Nothing did but one. I removed the Idle Air Control Valve and used electrical tape to block the ports. I started the truck and it initially revved to 1500 RPM and quickly went to 700 rpm. Normal by my understanding. Once the computer goes to closed loop and the Oxygen sensors are working LTFT is 0% and STFT is 5% or so, Again, normal. At this point it is idling horribly and dies out occasionally and is less responsive to throttle inputs.

What else have I done?

* I have shot carburetor cleaner into a vacuum port to observe O2 sensor reaction for detecting rich mixture. It does on both banks. Conclusion: O2 sensors are working properly.

* I have allowed the same port to pull extra air in to to observe O2 sensor reaction for detecting lean condition. It does on both banks. Conclusion: O2 sensors are working properly.

* I have cleaned the Mass Air Flow Sensor. This should not be the problem but WTH? Why not?

* I replaced the Idle Air Control Valve... No change what so ever.

* I have gone through several of the trouble shooting pages for these codes with no luck.

Remaining suspects... EGR valve. DPFE sensor, I have not ruled out a cracked intake manifold (just have not found it). Bad vacuum canister (iffy at best). and Satan lives in this engine.

4 March 2017:
* Okay, I hooked up a new DPFE sensor... No change.

* I removed the vacuum tree from the passenger side of the intake and plugged the port at the manifold... No change

* I removed the vacuum hose from the brake booster and plugged it... No Change.

* I unplugged the NEW Idle air control valve electrical connection... It started normally and only revved to 1500 rpm briefly ten fell quickly to a rough low idle and died out within a minute or two. I plugged it back in and started it again and it revved to 2200 rpm and took a bit to come back down to about 1100. I never warmed it all the way up as I know my problem still exists if it revves to 2200 rpm at start up. Cold warm, hot, it does not matter. It goes to 2200 at first start.

* the saga continues.

Any experience out there that might be able to help?

Thanks in advance.

 

[1997SCEBFEX]

what year? How many miles?
agree. sounds like unmetered air somewhere.
throttle position sensor?
egr?
original 02 sensors?
any other stored codes?

 

[Bedrck47]

Read the attached

http://troubleshootmyvehicle.com/ford/4.6L-5.4L/troubleshooting-p0171-and-p0174-page-1

 

[Bedrck47]

P0171 - System to Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

For lean and rich DTCs:

• Fuel system
• Excessive fuel pressure.
• Leaking/contaminated fuel injectors.
• Leaking fuel pressure regulator.
• Low fuel pressure or running out of fuel.
• Vapor recovery system.
• Induction system:
  • Air leaks after the MAF.
  • Vacuum Leaks.
  • PCV system.
  • Improperly seated engine oil dipstick.
• EGR system:
  • Leaking gasket.
  • Stuck EGR valve.
  • Leaking diaphragm or EVR.
• Base Engine:
  • Oil overfill.
  • Cam timing.
  • Cylinder compression.
  • Exhaust leaks before or near the HO2Ss.

P0174 - System to Lean (Bank 2) The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

See Possible Causes for DTC P0171.

 

[Mr67Stang]

what year? How many miles?
agree. sounds like unmetered air somewhere.
throttle position sensor?
egr?
original 02 sensors?
any other stored codes?

It is a 2000 model EB. 175k miles. The O2 sensors look new... like the previous owner could not figure it out either. He was a scammer. He had a 1998 transmission in it and told us it shifted hard because it needed a speed sensor. I ended up finding the '98 transmission has no place to put that sensor and had to get a 2000 model transmission so at least the transmission shifts normal and the speedometer works now.

With that said, it did not seem to have this lean running condition before I swapped the transmission. I know I have all the O2 sensors hooked back up and they are working as I can see them on my scanner when I go to live data. I thought that maybe that hose from the transfer case was my problem and I just forgot to plug it back into some port but I am reading that that is just a breather and does not hook up to anything...???

 

[Mr67Stang]

Read the attached

http://troubleshootmyvehicle.com/ford/4.6L-5.4L/troubleshooting-p0171-and-p0174-page-1

I went through every bit of that a few times... no questions answered but I did learn a lot. That guide is why I upgraded and bought a scanner with live data.

 

[Mr67Stang]

P0171 - System to Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

For lean and rich DTCs:

• Fuel system
• Excessive fuel pressure.
• Leaking/contaminated fuel injectors.
• Leaking fuel pressure regulator.
• Low fuel pressure or running out of fuel.
• Vapor recovery system.
• Induction system:
  • Air leaks after the MAF.
  • Vacuum Leaks.
  • PCV system.
  • Improperly seated engine oil dipstick.
• EGR system:
  • Leaking gasket.
  • Stuck EGR valve.
  • Leaking diaphragm or EVR.
• Base Engine:
  • Oil overfill.
  • Cam timing.
  • Cylinder compression.
  • Exhaust leaks before or near the HO2Ss.

P0174 - System to Lean (Bank 2) The Adaptive Fuel Strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.

See Possible Causes for DTC P0171.

I have been through all of this too... I fear I am about to remove the intake manifold and inspect for cracks.... The carburetor cleaner test did not find any.

 

[Mr67Stang]

I have edited the original post to add additional tests and observations I have done today.

 

[Gumbyalso]

I have a 2000 EB 4WD with 285K on it now. I had pretty much the same indications when it had about 210K. I went through several cans of carb cleaner listening for revs and lots of soapy water looking for bubbles. I started trying to diagnose by replacement up to and including the brake booster (which I had convinced myself was the source of the vacuum leak). After about 6 months of messing with it I finally took it to Ford and paid them an hour to diagnose. It was a cracked intake manifold (you have to love plastic intake manifolds) back near the firewall where I never would have found it with the carb cleaner. Cracked intake manifolds are common on those 5.4s for those years. Anyway, I had the manifold replaced and no problems in the last 75K miles. I think the new manifold is an improved design because they rolled the part number. There's even a youtube video on replacing them now. If I'd had that video back in 2010 when I had the leak I might have replaced the manifold myself, but I thought I would induce more vacuum leaks in the process. I've had this 2000 EB since new. It has the original 02 sensors.

 

[Mr67Stang]

I appreciate the input Gumbyalso. I am leaning heavily in that direction. Did you get your replacement manifold from Ford or one of the local parts houses? Also does anyone know if a 1998 5.4 manifold would fit on a 2000 5.4? I also have a '98 and it's manifold is aluminium instead of plastic.

 

[MikeA]

Mr67Stang,
If i read everything correctly, everything was fine with the 98 transmission and when you installed the 2000 transmission back in and hooked sensor back up, you started having all these problems, my question to you is,


Did you clear pcm after trans swap so the computor can learn the new settings for the trans?

 

[Mr67Stang]

Yes, I cleared the codes. In fact, right now there are no codes. But, I can see the idle run up to 2200 rpm at start up and see the LTFT go to 25% after getting to closed loop running. So, the codes will come back given enough time.

I checked the EGR valve today. I removed it and applied vacuum to it and it worked as designed.

I am removing the intake manifold tomorrow.

 

[grantpa]

What is the best replacement manifold to buy??? I've read differing opinions on the Dorman manifold. Is there an aluminum replacement-perhaps a performance-type-that will LAST and work??? I've got an '00 EB with the 4.6 and 177K with no issues-YET! But I'm trying to prepare myself for when the SHTFordPlasticManiflod. Suggestions?

 

[Gumbyalso]

I'm not sure, but I doubt it. Rock Auto shows two different Dorman part numbers - one for the plastic entire 2000 manifold (DORMAN 615188) and a different one for the aluminum lower intake manifold for the 1998 (DORMAN 615285). I got mine from Ford. I priced it online and then got my local dealer's part department to (begrudgingly) match that priced. (They have never done that since.) Possibly Dorman makes them for Ford. You may want to pay Ford an hour to diagnose first. Of course, that hour will cost you about as much as the Dorman intake manifold from Rock Auto. Diagnosing by replacing can be expensive sometimes, but I'm probably more guilty of that than most. I do get lucky on the first try more often than not.

I just read that you were removing the manifold. Saved yourself the diagnostic hour with Ford. I'd go with the Dorman. It's not too expensive.

 

[Mr67Stang]

I'm not sure, but I doubt it. Rock Auto shows two different Dorman part numbers - one for the plastic entire 2000 manifold (DORMAN 615188) and a different one for the aluminum lower intake manifold for the 1998 (DORMAN 615285). I got mine from Ford. I priced it online and then got my local dealer's part department to (begrudgingly) match that priced. (They have never done that since.) Possibly Dorman makes them for Ford. You may want to pay Ford an hour to diagnose first. Of course, that hour will cost you about as much as the Dorman intake manifold from Rock Auto. Diagnosing by replacing can be expensive sometimes, but I'm probably more guilty of that than most. I do get lucky on the first try more often than not.

I just read that you were removing the manifold. Saved yourself the diagnostic hour with Ford. I'd go with the Dorman. It's not too expensive.

Yes, I cant stand that I cant see the manifold well enough to be certain that it is not the problem. Once removed, I will thoroughly clean it and inspect it for cracks. I was not impressed with the condition of the upper gasket. the amount of dirt on top of the gasket where you would expect it to be clean by being compressed and sealed, was not. I am not stopping there. the whole intake is coming off. It may just need new gaskets.

 

[Mr67Stang]

For anyone following, I will let you know the problem appears to be solved. After removing the intake manifold and inspection revealed NO cracks but the gaskets appeared that they could allow undeterred air in, I replaced the gaskets and put it all back together. Just for good measure, I soaked the fuel injectors in marval mystery oil then hooked each one up to a 9 volt battery and shot carb cleaner through them and then re soaked them in the marval mystery oil. I also changed all 8 spark plugs while the manifold was off as it would never be easier to do then while the manifold was off. I fired it up and it no longer shoots up to 2200 rpm. It sounded good. I warmed it all the way up to get into closed loop running and my fuel trim numbers, both STFT and LTFT where bouncing around + or - 3%... PERFECT! Before, The LTFT was pegged at +25% and the STFT was about +15% to +19% at idle in closed loop. I still have to test drive it, but the numbers are where they should be.

Edit:// I put a little over 40 miles on it today and all is good. No more CEL/MIL on my dash. Thanks to everyone who helped.