Hi, I have a 2011 f350 Lariat deleted with 186,000 miles. I’ve put about 30,000 miles on it in the last year. Lots of towing cattle, horses, and equipment, lots of rough roads etc. it gets used hard but I take good care of it.

over the summer, it went to the dealer for leaking exhaust manifolds, a noisy fuel pump, and a/c recharge. $6k 😭. I wasn’t very happy with the experience. When I got it back it was leaking oil from the turbo, they reluctantly fixed it, and the 4x4 wasn’t working —- they Claimed that it wasn’t related and that the whole vacuum system needed replaced. I found a chunk of vacuum line missing from the pump to the system and fixed it for $1.

fast forward to now, about 6,000 miles later and the fuel pump is extremely noisy again. Always worst when between a full tank and 3/4. It quiets when I request fuel and gets loud at idle. Sounds like it’s over speeding, kind of like a plugged shop vac. Occasionally it throws low fuel pressure warnings primarily when I let off the throttle or am coasting down a long hill. It never has problems under acceleration or conditions where I am asking for fuel. It’s never had reduced power or any symptoms other than the sound and the message. I added some power service and that seemed to help quiet it down and get the message less frequently. This is the exact same pattern that it followed before the dealer replaced it.

I plan to try filters today but I think it’s something else because that didn’t work before. I plan to check all the fittings back to the tank and look for any way that air could be getting in. But it’s strange how it gets so much worse with a full tank and goes away below a half.

any help would be greatly appreciated!

 

So are you talking about the CP4 under the hood or the DFCM primary pump under the truck? For that kind of money, I'd assume the HPFP CP4 but could be wrong...

 

under the truck.

 

Ok if you change the filters, use Motorcraft only IMO if you change them... seems strange a new pump would schitt the bed at only 6k miles.

Not saying you don't know but there are two stops on the primary pump, one on the cap and one on the housing, that when tightened properly, will meet to "stop" the cap from being over-tightened (just FYI). Also, use clean oil on the new O-ring and threads on the cap as it will tighten on much easier and come off easier.

And make sure the foil covering or anything else did not fall into the tank because it's possible that it's causing a "low pressure" fuel situation if it got pulled into the pickup, or if the DFCM cap is possibly sucking air.

Did it do the same thing when the original DFCM initially started to get noisy?

And yeah, what's happening is weird... maybe someone smarter than I will chime in...

 

The new pumps are junk, I went through 3 of them, finally ripped it out and put a fass pump on it.
This is something you don’t want to mess around with as it will starve your cp4.

 

Really? You're talking the recent replacement Motorcraft DFCM pumps?

 

Yes and the control module.

 

Appreciate the info... so the control module was replaced three times as well?

I have an Air Dog 4G pump that's meant to replace the DFCM... but I want to supplement or feed the DFCM with the Air Dog, so they sent me the 10 PSI spring... I haven't installed but will at one point. I also want to buy a 50 gal Titan Tanks fuel tank and S&B's fuel pickup as well. I'll probably wait to do it all at once...

How many miles when this happened to your truck?

 

250k miles. Yes the module was replaced every time to. I learned that back on the 6.2s, couldn’t figure out why the module kept going out every 2 months. Finally replaced the pump and the the module quit failing. So now I replace them as a unit if one or the other fails. Might be overkill but cheaper then a tow.

 

Wow... how many miles on the latest set of DFCM/module? Appreciate the feedback too...

 

They wouldn’t last a week. We finally bypassed the module and run the pump off a ko signal and the pumps still would not run? Installed the fass system and it’s been flawless for the last 20k.

 

I had a lot of corrosion on my drivers side battery terminal. When I cleaned it off and tightened all the battery clamps it immediately went quiet. A big difference.

so I went and filled it up and it’s dramatically quieter and so far no low pressure warnings and less fluctuations in the pump but I think it is still louder than it should be.

then I just tried letting it prime with the truck off and backed the filter housing off a turn and then closed it again and that made a big difference immediately also. It completed priming right away after that and when I cycled the key it sounded much more normal.

im not convinced I have it solved but i think I’m making progress and will post back.

I appreciate all of the input!

 

what makes the motorcraft filters better? I’d just like to learn, not challenging.

 

Good to hear that did it. When I change my fuel filters, I prime it at least 10 times... and go over ten. I wait for the full 30 seconds each time and wait for the DFCM to shut off.

If I'm remembering correctly, I contacted Donaldson, who I think makes quality filters as I use their oil filter, about their primary filter and if it had the water separating media in it. They got back to me and said it did not. I'll double check my emails and see if I can find it.

Also, I believe the secondary filter, in the engine bay, has an air purge valve built in I believe.... Just be aware of counterfeit sets of Motorcraft fuel filters that EBay and Amazon, the FD4615 set the 11 to 16 trucks use. I bought a set before on Amazon and posted about it here. There was another post here about the secondary filter, a new feature that helps for when the fuel is cold... maybe someone can remember where it was posted. I'll try to find it.

 

Okay re-thinking this, I believe when you said you replaced the pump AND the control module, you meant the whole unit as it is called a Diesel Fuel Conditioning MODULE (DFCM) which is the primary pump/primary fuel filter/ water separator in one because there is no control module for it, or what I thought of when you said control module like a glow plug control module for example... correct?