P0171 & P0174 and Service Engine Soon Light

[Kenerator]

2004 5.4 EB. Service engine soon light came on. Idle is occasionally a tiny bit rough, but otherwise runs fine and there is no other indication of a problem. Used BlueDriver to check for codes. I received the following:


I cleared all the codes and the SES light went out, but light and codes returned a few days later.

I smoked the vac system using the brake booster hose as the smoke insertion point. Smoke came out of the throttle body, IAC, EGR valve and the two large hoses that connect to the air intake just prior to the throttle body. I pulled the air intake back enough to seal off the the TB and two large hoses, but still had smoke leaking at the IAC and EGR valve. No smoke anywhere else that I could see. All of the little vacuum lines appeared to be intact.
Question - Is it normal for the IAC, EGR valve to leak smoke?

Thinking that maybe there was an intake manifold leak or something like it, I put the intake back on started the engine. While running I sprayed starting fluid around the top of the intake manifold and throttle body. There was no discernable change in RPM.

So, unless my smoke test was done incorrectly, there appears to be no vacuum leaks (smoke test) or intake leaks (starting fluid test).

Were my test methodologies erroneous?
Should I start looking at component failures? i.e. O2 sensor, MAF, etc?

Any thoughts are appreciated. Thank you!
Ken

 

[Hamfisted]

It is normal for a small amount of smoke to escape from the IAC and EGR valves. It is not normal for smoke to escape from the small hoses prior to the throttle body, or any other hoses. I would connect the smoke machine's hose to the Evap vacuum supply nipple there at the top of the throttle body elbow. Just to see if the brake booster is leaking.





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[Kenerator]

Great idea Hamfisted!
I inserted the smoke at the top of the throttle body elbow as suggested. I got smoke from the usual suspects - IAC, EGR and side of the throttle body, but no smoke at the brake booster or booster hoses. However, I did find smoke coming out from under the fuel injector of the first cylinder on the passenger side. The yellow arrow in the photo is pointing where the smoke was present. The smoke looks like glare and is difficult to see in the photo. It was much more visible in person. I suspect this means bad intake manifold or intake manifold gasket.
Question - Doesn't seem plausible, but is it possible that the injector, or injector o-ring is bad and leaking?
Again, any thoughts are appreciated.
Thank you,
Ken

 

[whtbronco]

Sure it's possible you have an injector o-ring that's failed and from the looks of it I think you're on to something. I'd say it's unlikely to be the injector itself. I haven't messed with these fuel rails/injectors yet, but it's a pretty cheap and simple process to pull the fuel rail and replace the injector o-rings on the vehicles I have done so on.

 

[whtbronco]

I looked up the process in AllData. It doesn't look terrible, but AllData shows it's a more involved process than any I have done to remove the fuel rail, 2.2hrs of book time. I think I could do this on a GM 3800 in 30 minutes.

 

[Hamfisted]

To leak enough air to trigger a P0171 and P0174 at the same time it would have to be a good size leak. Not likely with a fuel injector O-ring. Much more likely to be the intake manifold gasket. Did you look around the engine with a bright flashlight during the smoke test ?



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[whtbronco]

Hmm, good point. A single injector o-ring seals a rather small gap.

 

[Kenerator]

Yes, I looked for several minutes with a bright flashlight. I scanned every hose that I could put my eyes on. There may have been a little bit of smoke at the last cylinder, same side, but I couldn't tell if it was a leak or if it was smoke carried over from the IAC. The brake booster, vac lines, vac reservoir, both sides of the engine, etc, all appeared to be intact.

I also rescanned and P0171 is now the only confirmed trouble code. P0174 is no longer indicated.
Question - Is the passenger side Bank 1?

If it was Summer, I would tackle the gaskets myself, but since it's cold in my garage I may take it to the shop. Is $1,200 - $1,600 a good estimate for a shop to fix?
What is the level of urgency for this fix? <25 miles, <100 miles, <500 miles?

Thanks Hamfisted and whtbronco for your input.

 

[riphip]

Before I spent that kind of $$$, I would check/replace any/all rotted vacuum hose, hose assemblies, PCV & hose & elbows that look rotted or feel spongy. Does not cost near the gasket replacement but will need to be performed especially if nothing has been done during that 154k miles. I replaced most of mine for under $200 and a little grime on my hands (use Nitrile gloves). Go to www.rockauto.com
I do not know the current discount code but someone else may chime in. There is a vacuum assy behind the battery also. Heat and age are terrible on these vacuum lines/hoses.

 

[Kenerator]

Thanks riphip. Many of the hoses, elbows, and the PCV have been replaced. I specifically looked for smoke behind the battery. As far as I can tell the vac/evap systems are intact.

 

[whtbronco]

Well the codes are for running lean which is not good. It also implies that you have unfiltered air entering the combustion chamber which can lead to increased wear in the valves, pistons, rings and heads. In my opinion performance issues should not be put off any longer than absolutely necessary as they can lead to other problems.

The job pays 6hrs, plus parts. I'll let you decide if it's worth $1000 for labor or considering the purchase of a small heater and some mechanics gloves if the garage temp is an issue.

 

[Hamfisted]

Yes, the passenger side is bank one . I'm not sure what the going rate for an intake gasket change is in your area. Have them replace the coolant crossover gaskets ( Fel Pro ES-71213 ) while the intake is off. Since that is a common failure item as well, and the intake has to be removed to replace those gaskets anyway.



Coolant Crossover Gaskets ( Fel Pro ES-71213 )





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[Kenerator]

Thanks whtbronco. Great input! Thanks for looking up and posting the hours.
Thanks Hamfisted. Excellent idea.

Actually, I discovered the following YouTube https://www.youtube.com/watch?v=IJJTlDrCaUQ by FordTechMakuloco. It doesn't seem like it's too bad of a job. If the book says 6 hrs like whtbronco says, then it will take me 12 hrs. That's not too bad. My local Napa Auto Parts has all of the Fel Pro gaskets and there is an added benefit of being able check all of the hoses and their connections up close.

If I do this myself, in addition to the intake gaskets, I plan on replacing:
Throttle body gasket
Thermostat + gasket
Crossover gasket
Spark Plugs
Any suspect hoses

Anything else should I do while I have it apart?

 

[Hamfisted]

If you don't already have one, get yourself a good 3/8" torque wrench. Proper torque is very important with all these components, and you're only working with plastic. You don't want to over torque stuff. A good intake gasket set should come with new fuel injector O-rings, but if yours doesn't, pick up a set of those too. The coldest you can go on the thermostat is 180. Pickup a couple gallons of Zerex G-05 or Ford Gold Premium coolant too. Since you'll have to drain the coolant for the job anyway.





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[RichardH]

I can almost swear that I had the same codes for my former 2001 Expedition - I replaced the hose that connects to the rear of the throttle body and it fixed the codes.

Dick

 

[whtbronco]

Kenerator, you sound like me, I generally double the book time for myself as well. After I have done the job a few times I can get close to the book time, but certainly not the first time.

 

[texasscot]

Thanks whtbronco. Great input! Thanks for looking up and posting the hours.
Thanks Hamfisted. Excellent idea.

Actually, I discovered the following YouTube https://www.youtube.com/watch?v=IJJTlDrCaUQ by FordTechMakuloco. It doesn't seem like it's too bad of a job. If the book says 6 hrs like whtbronco says, then it will take me 12 hrs. That's not too bad. My local Napa Auto Parts has all of the Fel Pro gaskets and there is an added benefit of being able check all of the hoses and their connections up close.

If I do this myself, in addition to the intake gaskets, I plan on replacing:
Throttle body gasket
Thermostat + gasket
Crossover gasket
Spark Plugs
Any suspect hoses

Anything else should I do while I have it apart?

It may be worth getting some spare plugs for the injectors and coils. These get brittle with age and the retaining tabs often come off when you’re messing with them which can lead to random misfires down the road.
it’s been suggested here that removing the wire pins using a special toolset and switching the plastic plug body is better than soldering on new ones. Either way, with the inlet manifold off it’s a lot easier than reaching down and in to strip and solder tiny wires.

 

[Kenerator]

Copy on the injector O-rings, torque wrench, crossover gasket, thermostat, Zerex G-05, hose on the rear of the throttle body, and spare plugs for injector/coil connections. Thank you.
Seems like Motorcraft spark plugs are hard to get around here. My local Napa Auto has NGK Iridiums, Ruthenium HX, Laser Iridium, and Platinum. Thoughts on these?
Lastly, I believe the gap should be 0.052". Can anyone confirm?
Thank you so much everyone for your input! Not exactly what I wanted to do during Christmas break, but y'alls input has gotten me well prepped!

 

[Hamfisted]

You can order any sparkplug from Rock Auto and get it in a few days. Some plugs recommend .054 and others recommend .052 . Just depends on what you end up installing. I used NGK Iridiums in mine when I replaced the head gaskets a year ago. They're fine. I probably won't have to replace the plugs again. I don't notice any "performance" difference over the stock Motorcraft SP-479 Platinums that were in it before. If you have any concerns, I would just stick with the Motorcrafts at a minimum.

Sparkplugs available online at Rock Auto







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[Drae]

I've had the intake manifold off of my 03 5.4 a couple of times now. Not a bad job just time consuming getting things out of the way for clearance. The first time I had to replace the leaking Dorman Intake Manifold that someone put on there at some point before I bought it. Not sure if it was just gaskets or if it was cracked but once I found out it was Dorman it was getting pulled regardless for a Ford replacement.
The second time was after I brought it from Alaska to Texas and it began to overheat while running the A/C often. It turned out to be the cylinder head temperature sensor which was right under the intake manifold in the front. My suggestion would be to replace all that was mentioned above and that sensor as it's about 10 to 12 bucks on Rockauto. Also take plenty pictures of everything you remove as a reference for when you're putting it back. I even got out masking tape and colored markers for hoses or whatever to color code things to make it that much easier.