Hi guys. Posted about this on another site but I'm looking for as many opinions as possible. My truck is a 2004 F-150 5.4. It had 119k miles when I bought it last Fall, and I'm only up to 120k now.

It ran perfectly fine until last month, we were driving on the highway and suddenly the truck felt like it was missing, and black smoke started coming out of the tailpipe. I was losing power and barely made it to a parking lot before the truck died. The truck wouldn't start after that so we called a tow. I was afraid it was a catastrophic failure so I had them bring it to a shop rather than home.

The shop diagnosed a bad fuel rail pressure sensor, and replaced it (for about 10x the cost that I could have done it myself, ugh). Everything seemed back to normal until a week later, when I got a check engine light. Had the truck scanned and the codes were P0191 and P0452. It still seemed to be running fine so I didn't take any action right away.

Fast forward to this past Sunday and I'm right back to where I started. I was dumping some trash at the local transfer station and when I went to leave, the truck almost stalled out. I punched the gas to keep it going and sputtered my way home, puffing out black smoke the whole way. Thankfully I only had a mile to go because the truck died as soon as I pulled into the driveway.

So that's where I'm at. P0191 is a fuel rail pressure sensor fault, so either the brand new unit is defective, or something is causing it not to read right. I'm guessing P0452 is related.

One person suggested checking out the fuel injectors, so that will be my next step. Anyone have any other ideas?

2004 F150 5.4 Lariat Supercrew, 120k miles
P0191
P0452
black smoke
stalling
hard to start

 

Check your FPDM for corrosion and cracking. It's above the spare tire.

 

Check those injectors before trying to start again. If they are leaking it could hydrolock.

 

"so either the brand new unit is defective,"

That is the most likely IMO. Where did they buy the part from and what brand is it? Very few parts manufacturers are bothering to test their parts before they send them out so you, the lucky consumer aka the guinea pig, get to test them for them and then make the repair again if the part is defective. NAPA and Motorcraft (Ford) parts are usually ok but anything from a DIY auto parts store is a gamble.

The shop that replaced the part should warranty their work and the part and should fix repair this at no charge. If you paid for the repair on a credit card, you may want to take this to another shop and have it repaired and (assuming that the 2nd shop finds that it's the same problem that you already paid to have fixed) then dispute the charge for the first repair through the CC company.

Just hope that the excessive fuel didn't ruin your cats!

 

Read this if you haven't.

https://www.obd-codes.com/p0191

And this

https://www.obd-codes.com/p0452

Did the shop use a scanner and verify the fuel pressure?

 

Thanks for the replies guys. The FPDM is in good shape and installed on standoffs, I believe the previous owner did that. The pressure sensor the shop installed is a part# FPS507.

This afternoon I replaced the fuel filter and then made sure I was getting a 5V signal at the pressure sensor and checked the fuel injectors for power too.

While I was under the hood I think I found the cause for the P0452 code and -hopefully- the source of my problems.




This little check valve at the evaporative emissions solenoid was full of dirt and after cleaning it out and giving it the suck/blow test it was allowing air to pass both ways. I'm going to replace it ASAP and see what happens.

 

I replaced that check valve this afternoon and took the truck for a short test drive. Started up fine, check engine light is gone, no black smoke, no hesitation, no stalling, everything seems normal. I'm hesitant to say it's fixed because I already thought that once, but it's looking good so far.

 

Not fixed. Ran fine this morning then failed again this afternoon. That check valve was once again full of crud and allowing air to pass both ways. I don't know what to do anymore.

 

What kind of crud? Can you follow the line to the source?

 

It honestly just looks like orange dirt.

I just started it up and tried unhooking the vacuum line with the bad check valve and nothing changed whether that line was hooked up or not, it was still running terribly and puffing black smoke no matter what. I unhooked the battery and the CEL is gone but it there is obviously still something bad going on.

 

I wonder if you can put an inline fuel filter in the line going to the check valve to catch the crud before it gets to the valve?

OTOH You need to find out where that curd is coming from and fix the problem there.

 

I've verified the evap purge and canister solenoids are functional and receiving the proper voltage.

I tried bypassing the FPDM and that didn't change anything, so that suggests the FPDM isn't the problem. I could hear the fuel pump running, so I don't think the pump is the issue.

 

Still getting nowhere with this thing. Last move was to replace all 8 fuel injectors, did nothing. Running out of ideas. Probly gonna have to take it back to the shop and pay 2 arms and 3 legs to have them "fix" it again.

 

Try finding the source of the contamination in your vacuum line. It might be a vacuum hose that is disintegrating internally. Or the air filter is coming apart, some of those did have an orange colored seal.

 

Thinking about this more. How does the air filter look is it all in one piece?