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I am continuing my quest to solve a problem with a vacuum leak. I have attached a few photos. The freeze frame, which I just learned about, thanks to #BareBonesXL. I have fixed a couple major vacuum leaks the were sucking in unmetered air. I was getting the P0171 and P0174 engine code errors around 10± miles. Now I am getting the same errors about 28± miles after a error code reset. (Testing this 2X.)
One of my problems was the EGR valve when I was doing a smoke test. The original EGR was leaking a lot of smoke and the new Napa Auto parts replacement is leaking some smoke from the UFO thing on top of the steel casted portion of the part.. Should a good EGR valve leak any smoke?
I have also seen the original idle air control valve is leaking some smoke. The
I am using seems to be doing the job. My first test was sending the smoke through the front of the air intake after the air filter before the MAF sensors. This time I used the brake booster line and pushed the smoke the other direction and got smoke from the new ERG valve and a little from the Idle Air Control Valve again. My first test I saw a little of smoke coming from the IAC valve but is was so small I didn't think is would matter. I replaced the EGR since is was leaking a lot of smoke. Much more that the new replacement. There was a small crack in the cast iron part of the unit. With the new EGR Valve. Now there is a little smoke coming from the thing on the top (not sure what to call it, maybe a diaphragm).
The freeze frame data does not show P0174 and only P0171. When I run the scan I see both P0171 and P0174 so this is a little odd.
I have not yet done a smoke test through the exhaust to see if I have and exhaust leak causing P0171 on bank 1. Maybe and exhaust leak or maybe low fuel pressure??? Not sure how to check that low fuel pressure.
Any suggestions are appreciated. I don't want to start replacing parts throwing money at this without a proper diagnosis. I am using a Blue Driver OBDII scan tool. This is my only scan tool experience. I have not use any other scan tools.
Thanks for any help pointing me to fixing this issue.
The fuel trims are a problem
Need to be within 7 percent
Yours, at 21 percent, are compensating for an intake leak or other air leak past the throttle plate (unmetered air)
Pretty hard if not impossible to verify on a 5.4 with the lower plenum
That's where they usually crack (at the bottom plenum)
I'd remove the intake and check it visually real close
Plan on replacing it
Actually, I think that your freeze frame data shows that you might be running out of fuel. Low fuel pressure. Engine is at 1288 RPM, engine load is 63.1%, which means you opened the throttle, but fuel trims are close to 50% (add long and short trims to get total trim). And you're at 45 mph.
Basically it shows that you were at speed, you hit the gas, and the PCM tried to add fuel by opening the injectors longer but not enough fuel is being added. Seems like fuel pressure at the rail, or wrong injectors.
But the missing P0174 is odd. If it was fuel pressure you'd expect it on both banks. P0174 might be "Pending". That's another screen on your scanner. You should be able to use Live Data to watch fuel trims on both banks while you drive. The good scanners will record data plots for later review. They will also show O2 sensor data, which might tell you something.
The big clue though is that it's not an idle RPM air leak. It's under load at higher PRM.
Are you sure that there's not more info down the screen? Usually engine temperature is shown.
Maybe I'm missing something, but I don't see any mention of the rubber elbow at the opposite end of the PCV valve on the intake. They rot and crack, and cause 171/174 codes. It also may be in the area of the IAC. Check the rubber elbow on the back of the intake.
Actually, I think that your freeze frame data shows that you might be running out of fuel. Low fuel pressure. Engine is at 1288 RPM, engine load is 63.1%, which means you opened the throttle, but fuel trims are close to 50% (add long and short trims to get total trim). And you're at 45 mph.
Basically it shows that you were at speed, you hit the gas, and the PCM tried to add fuel by opening the injectors longer but not enough fuel is being added. Seems like fuel pressure at the rail, or wrong injectors.
But the missing P0174 is odd. If it was fuel pressure you'd expect it on both banks. P0174 might be "Pending". That's another screen on your scanner. You should be able to use Live Data to watch fuel trims on both banks while you drive. The good scanners will record data plots for later review. They will also show O2 sensor data, which might tell you something.
The big clue though is that it's not an idle RPM air leak. It's under load at higher PRM.
Are you sure that there's not more info down the screen? Usually engine temperature is shown.
that is all of the freeze frame data. there is no second page, i just looked.
Maybe I'm missing something, but I don't see any mention of the rubber elbow at the opposite end of the PCV valve on the intake. They rot and crack, and cause 171/174 codes. It also may be in the area of the IAC. Check the rubber elbow on the back of the intake.
I saw a video of that last night. I reconnected the smoke machine and did more testing. Smoke was coming from in that are way in the back but it looks like it is coming from the IAC. I did look for the rubber elbow and didn't see it. From what I saw on the video it creates the vacuum for the ventilation controls. Is this correct? I may have to take stuff apart to get to it.
Today I replaced the fuel filter. Before I changed it out I rented a fuel pressure gauge to connect to the fuel rail. I read somewhere that a user of the rented unit didn't have a long enough depressor for the Schrader valve in the rail. I was not getting a pressure reading and tried several things and finally was able to get a 14# reading before and after the new fuel filter up in the frame. Not sure I was getting aproper reading since I wasn't able to get air out of the pressure line. I kept getting air bubbles coming out. I took apart and reconnected several time. I was getting fuel out of the valve with the motor running, but not much, and finally was able to get a a pressure reading but I am not confident the reading I was getting was correct at 14#.
Again the truck does have 281000+ miles on it so maybe the fuel pump is bad. But I don't know.. The fuel filter I change was not original BUT I know the filter is not clogged. :-)
You can take the Schrader valve right the hell out and re check the pressure
At 14lbs you are barely running
I would replace the fuel pump just for GP's at this point, fregardless of the pressure reading
Do a volume test for the pump
Sometimes the little hose in the tank will look like this and the truck still run 04 F150 4.2 fuel pump. The truck still ran, just like puke
Codes 172 and 174...
How many of you have ever looked at the "H" section of the PCED?
That is the section you "camp out" in for fuel concerns like the lean codes above
Those common codes are the reason they call the PCED "The H manual"
There is about a hundred pages in the H section, and you are to check about 200 things
You'll find (quickly) that you do not have what it takes to perform some of the pinpoint tests (even when sitting at a dealer with tens of thousands of dollars in special tools at your fingertips)
All of the computerized electronic engine controls are based on the assumption of a certain fuel pressure. If you checked pressure and didn't get the right number you should just stick on that problem until you fix it. Everything else is a waste of time if fuel pressure is not correct.
I did look for the rubber elbow and didn't see it. From what I saw on the video it creates the vacuum for the ventilation controls. Is this correct?.
No. Locate the PCV valve on the passenger side valve cover and follow the hose to the back of the intake where the elbow is located. Remove the elbow and thoroughly inspect for cracks while squeezing it. No need to remove anything else.
Also, get a can of MAF cleaner and spray the MAF sensor in the intake tube just past the air filter. Do not touch the wire, just spray clean.
If your new EGR is leaking smoke, it is not sealing right. A good one should not leak at all. The diaphragm vent can let out a tiny bit, but if you see visible smoke, it is faulty or mis-seated. I would cap that line and re-test. Also check the PCV hose and intake gaskets—those are common sources for P0171/P0174 together.
Update.. @manicmechanic007 @BareBonesXL
I ended up taking the Schrader valve out and still got 14# pressure with the rented fuel pressure tester. I ordered a new fuel pump and installed it. I rented (for free) from Orielly's auto parts after I got the new pump. Retested and still got 14# then installed the new pump and got 32# of pressure. I have put a couple hundred miles on the truck and lean codes are have not come back!
Thanks for your help guys!!!!!!!
BUT now an EVAP code came P0455. Going to start a new thread for that on.
