P0171 1997 Ford Expedition

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Tommie

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Yeah, I just replaced my head gaskets at 220k . Had them rebuilt while it was apart. Wasn't losing power, just a build up of pressure in the coolant reservoir and started seeing soot in the coolant. Now that everything's back together and running right I only see about 3-4 lbs of pressure in the reservoir. Cleaned the intake runners with Marvel Mystery oil and rags, they were carboned up, same as the intake ports. The machine shop cleaned up the heads and installed new springs and seals. I installed new rocker arms as well during reassembly.

Very nice!!! I'm eyeing a rebuild next year and looking at getting a stage 1 cam from modular head shop possibly if I can find more info on torque curves and peak power numbers on the 5.4, any idea when ford used the PI heads? I have the 2001 Eddie Bauer 4WD so hoping I have the PI head.
 

Tommie

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Eugenia this video will help you or a friend who can turn a wrench to get the job done....

 
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Eugenia Bermudez
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The shop that replaced the fuel pump and EGR preformed a smoke test on it when the found the EGR was bad. they replaced it and then after driving it 140 miles check engine light came on P0171 thats when they said it was the fuel pump. they replaced it i drove it for a few miles and it was losing power again worse. I replaced the battery and alternator myself cause I didnt want to pay another $500+ to have it done. Now it's running strong but now I hear a coolant leak. I have a feeling the thermostat is bad too. Ill find the leak get it fixed and replace the thermostat.
 
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Eugenia Bermudez
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Oh yeah, the shop mechanic told me he did another smoke test after he replaced the fuel pump and said there were no leaks. We'll see.
 

Hamfisted

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Very nice!!! I'm eyeing a rebuild next year and looking at getting a stage 1 cam from modular head shop possibly if I can find more info on torque curves and peak power numbers on the 5.4, any idea when ford used the PI heads? I have the 2001 Eddie Bauer 4WD so hoping I have the PI head.

The PI heads were introduced on the 5.4 motors in '99 . They actually have a "PI" embossed along with the part number on the head itself ( passenger side right above forward exhaust port , driver's side rear port... heads are interchangeable...).



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Tommie

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The shop that replaced the fuel pump and EGR preformed a smoke test on it when the found the EGR was bad. they replaced it and then after driving it 140 miles check engine light came on P0171 thats when they said it was the fuel pump. they replaced it i drove it for a few miles and it was losing power again worse. I replaced the battery and alternator myself cause I didnt want to pay another $500+ to have it done. Now it's running strong but now I hear a coolant leak. I have a feeling the thermostat is bad too. Ill find the leak get it fixed and replace the thermostat.

Has the intake manifold gaskets been replaced? That is notorious for vacuum and coolant leaks.... I know you plan on keeping the truck its def worth the work because its a known fault with many issues. Scanner Danner on youtube does a lot of trouble shooting videos on this that will show you what I mean...




If you do this then replacing the PCV is super easy and I'd highly recommend it.
 
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Eugenia Bermudez
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I just want to thank all of you who have responded and offered great advice about repairing my 1997 Ford Expedition 5.4l 4x4, and not treating me like some dumb girl. I'm not a certified auto mechanic but I have done plenty of repairs on several makes and models and am willing to learn more. And I've done alot of research online and even have a shop service and repair book for my Ford that weighs a ton. It's actually three book set. So I do know a little about vehicles. So I appreciate all of the comments and advice and respect from all of you. Love my Ford!
 
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Eugenia Bermudez
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Update. I'm at my wit's end. Now it seems like my truck has a coolant leak somewhere and I used a camera to try and locate it at the back passenger side of the engine. I couldn't see where the leak is but after running it then shutting it off I could hear it. Heater core? Coolant bypass tube? Intake manifold? All the above? Lol Can't be anything easy to spot of course. Anyone live close to Eureka CA that could help me? I'm losing hope but still have faith. Love my Ford.
 

Tommie

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So the leak is enough to see it visually? Is it going into a spark plug hole?

First thing I'd do is get a clean and DRY paper towel and hold it at the junction where the hoses leave the firewall on the passenger side, this is the piping to the heater core. If no sign of water leaking, check every pipe starting from the highest point to the lowest to clear out a coolant hose issue.

Then I'd inspect the area around where the head meets the block and see if there is a leak there, hopefully not because that's worst case scenario.

But like I said above the intake manifold gasket if never been changed MUST be bad, so that's a given to do regardless and would explain why you have the codes, and likely means you have a fouled coil or two like I did, just been through this my self.

Like Ham said I'd test the coolant system and see where the leak is, I'd look at the coolant cross over on the front near the Thermostat housing but across on the passenger side, that's where my leak was. and the most rear passenger side too like it sounds you possibly have.

Goodluck!
 
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