03 Expedition P0171 Help
I just picked up a 2003 Expedition XLT RWD with a 4.6L SOHC and 163k miles. It is throwing code P0171 Too Lean on Bank 1. The IAC Valve had an internal short to the case, I found a Collapsed PCV Hose and a broken vacuum line and fixed all of those but still have the lean condition and the code keeps coming back. The only noticeable symptom is a little shaking at idle, under load everything seems fine. It has new Upstream O2 Sensors and Catalytic Converters, but the Downstream O2 Sensors look like the original ones so I am going to swap them tomorrow clear the code and see if P0174 comes up instead. Here is my freeze frame data, any help would be greatly appreciated:
FUELSYS1 CL FUELSYS2 -- LOAD_PCT(%) 21.6 ECT(*C) 74 SHRTTFT1(%) 5.5 LONGFT1(%) 26.6 SHRTFT2(%) 3.9 LONGFT2(%) -15.6 RPM(rpm) 803 VSS(km/h) 31 SPARKADV(*) 15.0 IAT(*C) 9 MAF(g/s) 6.58 TP(%) 19.6 O2B1S1(V) 0.745 SHRTFTB1S1(%) 5.5 O2B1S2(V) 0.330 SHRTFTB1S2(%) N/A O2B2S1(V) 0.660 SHRTFTB2S1(%) 3.9 O2B2S2(V) 0.270 SHRTFTB2S2(%) 99.2 |
Check to makes sure the fuel pressure is up to specs. If it is then you still have a vacuum leak. If you don't find any issues with the hoses it can be the intake manifold gasket.
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Isn't this the one with the integrated coolant crossover tube on a plastic intake manifold? They're known to crack and leak where the coolant crossover is
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Originally Posted by Skauber
(Post 15934735)
They're known to crack and leak where the coolant crossover is
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On the 2v 4.6l (or was it the 5.4?) they have the plastic intake manifold with an integrated aluminum coolant crossover tube, which also shares the same gasket as the intake manifold. The plastic gets brittle and cracks near the coolant crossover, voila, vacuum leak, or worse, coolant leak into the intake ports.
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Originally Posted by alloro
(Post 15934705)
Check to makes sure the fuel pressure is up to specs. If it is then you still have a vacuum leak. If you don't find any issues with the hoses it can be the intake manifold gasket.
A few years ago I replaced an Intake Manifold on my 2001.5 Mustang GT with a 4.6L SOHC, it had the plastic/aluminum crossover and started leaking coolant but never threw a code. I put a Dorman one on and it worked fine, came with the Gaskets and everything. Does anyone know if its the same procedure for the Triton 4.6? Thanks for the input. |
2 Attachment(s)
Originally Posted by CycleVIN
(Post 15935497)
Do you know what the correct spec is at idle and under load for fuel pressure? I heard it was 55-65 psi.
Does anyone know if its the same procedure for the Triton 4.6? Thanks for the input. |
Originally Posted by alloro
(Post 15935662)
Fuel specs and intake R&R procedures are attached.
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About 5 days after I did the fuel filter, the light came back on. I ended up replacing the intake manifold gasket, it was blown out at the back of Cylinder 4. While I was in there I noticed the gasket that goes in between the aluminum upper intake manifold, and the plastic lower intake plenum was also leaking so I replaced it as well. While I had the intake manifold out I checked the plugs and they were all Motorcraft and looked pretty new. The gap was good on them so I just re-installed them. I swapped out the O-Rings on the injectors, and found one injector with a broken tip. I swapped that injector out to the other bank a few days ago have not had a code come back yet. Hopefully if the CEL does come back it will be on Bank 2 and then I will know it is the Injector.
https://cimg2.ibsrv.net/gimg/www.for...84ce722eaa.jpg |
Originally Posted by CycleVIN
(Post 16070242)
I checked the plugs and they were all Motorcraft and looked pretty new. The gap was good on them so I just re-installed them.
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Originally Posted by alloro
(Post 16072358)
While I understand the concept of don't replace what isn't broke...considering how difficult they are to replace I think I would have done so and then taken comfort in knowing they were good for another 100K miles. But that's me. $$
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