Hello. I have seen my specific issue on this forum, and have tried the provided solutions (so please be patient with me). The truck has been deleted and I have installed the new fuel pump to prevent the known potential issue of fuel pump failure (I went beyond just installing the Disaster Prevention Kit).

I have a 2015 Ford F250 with the 6.7 diesel motor. Love this engine! I keep up with all routine maintenance including checking for water in the fuel and changing the fuel filters. For this application, Ford has an upper filter cartridge on top of the motor, and a bottom filter underneath the truck. I have performed this maintenance previously with no issues.

When I went to do the filter change this year, I could not get the vacuum to quit draining fuel. The normal process is to drain the fuel in the fuel filter housing by turning the yellow valve and draining the fuel (normally less than a quart of fuel drains). I unscrewed the fuel cap and this did not solve the problem. I next unscrewed the filter housing and this managed to break the siphon and fuel stopped flowing. After I thoroughly cleaned the area and lubricated the new O ring on the fuel filter housing I put everything back together and performed the procedure to prime the fuel system (turn key on, wait 30 seconds, turn off, repeat 6 times). This is where my problems began.

After the fuel system primed, I was able to get the truck to start and run. However, it took a longer key action to get the vehicle to start (which is not unusual for the first start after a fuel prime procedure). Prior to the fuel filter change, it normally only took maybe 3 seconds to start the vehicle when engaging the key. It now takes probable 6-10 seconds of cranking before the truck will start. It does not matter whether I wait for the glow plugs to cycle or not. Also, the same prolonged cranking issue exists if I shut the truck off and try to restart right away (or if I wait).

I made sure I fully tightened the fuel filter housing (making sure it was tight at the top). It is difficult to know how far to tighten it, but in the past it was not overly tight and I normally just take it around to make sure the sensor connector is oriented properly.

I took everything back apart and again cleaned the filter housing. I put a light coat of grease on the O ring and reassembled everything and primed the fuel system. This did not help. I should note that the same previous siphon existed and I could only stop fuel flowing after loosening the fuel filter housing.

I took everything back apart and used another new O ring from another fuel filter pack. This did not help.

So I don't know where to go from here (aside from taking it to a mechanic). I figured maybe try here first to see if there is something I am missing. I think the extended cranking issue is being caused by air getting in the fuel system somewhere since the issue did not exist prior to the fuel filter change.

(1) Is it possible that I am getting air in the system from the upper filter? I changed it but have not disconnected and reconnected since the filter swap.

(2) I have driven the truck even with these issues and do not notice any performance issues (the only issues are the need to crank longer on startup). Is it possible that this could harm the engine or is it just an inconvenience?

Thanks for any assistance or ideas that you folks can provide!

 

Hello and thanks for the response. No, this is a cartridge type filter (on the bottom). It slips into the filter housing then the whole thing screws in. You don't preload it with fuel (which is what necessitates the need to prime the system). Thanks!

 

I need to do a little more reading before I can offer any worthwhile suggestions.

The 6.7 is new to me also.

 

Make sure the lower fuel filter housing is filled with fresh diesel then prime it with a capable scanner (Foxwell NT510 Elite w/ Ford for instance) if you have one then the scanner can run active test on your behalf to the low pressure fuel pump continuously to bleed the air out.

 

2015 Ford F250 SuperDuty with 6.7 diesel and 4WD automatic transmission VIN "F" (8th character)

So a quick update to my maintenance headache. Remember, I was having ZERO problems before I performed this "simple" maintenance (which I have successfully completed in the past).

I took the truck today for a short trip to see how it would do at highway speeds, thinking that highway speed might be able to help the system purge the air. Drove it 50 miles at highway speed (65 mph) with no issues aside from the aforementioned extended cranking at initial startup. Truck ran fine the entire time. Parked it at our destination and truck was shut off for 5+ hours.

Amazingly when I went to start the truck to return home it was back to a normal crank cycle and only took the regular short crank to fire over! Yay! Problem solved!!

My life is never that easy....

Getting back on the interstate I had to put more immediate pressure on the accelerator to merge into traffic. Truck did not like that at all and produced an "idiot" light (which I took personally but did feel was merited) and a "Reduced Engine Power" alert.

I ended up limping the vehicle home. Power was greatly reduced (60 mph or less maximum on highway, under 20 mph sometimes). I thought truck was going to die so I backed off the accelerator and this actually helped it regain power. Then it would downshift, lose power again, then regain power as I backed off accelerator. Frustrating.....

Based on the prior advice, I will be taking my truck into the service shop to get the air in the injectors purged and hopefully this resolves my issue.

I am thinking I may not attempt to do the fuel filters myself in the future....

I will continue to share developments on this issue as it may benefit others going through a similar problem.....

Uggggg.....

I sincerely appreciate the advice and input..

 

So you have multiple issues any DTCs causing the limp mode? Check and see if you have P259F.

 

So, the vehicle made it to the repair shop and has now undergone (professional) diagnostic scan. The repair shop indicated it was code P0087 Low Rail Pressure. They will be replacing the lift pump.

I asked if the fuel filter change had anything to do with the lift pump failure. The tech indicated that there was no way that the fuel filter change could have caused the lift pump to fail, and that it was just coincidental.

So I have just a few followup questions for the forum.

(1) Do you folks generally agree that the lift pump issue was coincidental to the fuel filter change?

(2) Is it possible that the long crank issue I was experiencing caused the lift pump to fail?

(3) I do understand that if I have air in the system in the future after a fuel filter change that I always have the option of bleeding the injectors (as suggested previously). However, aren't these systems made to purge air on their own? Wouldn't driving the vehicle at highway speeds purge the system through the increased fuel flow?

(4) The vehicle has approximately 135000 miles on the motor. Is it abnormal for the lift pump to fail at this mileage?

Thanks everyone! Once the repair is completed, I will report back the final resolution and whether this resolved all the issues.

 

Lets hope that diagnosis is FINAL.
I say that because if the power that operates the lift pump is not verified, just like a gas fueled engine, the pump can't deliver what it should.

Thank you for the update..

 

I picked up the truck today. I spoke to the mechanic who worked on the vehicle and he said that the lift pump was original to the vehicle and was simply just worn out (sounded like gravel grinding). He again reiterated that the fuel filter change was coincidental to the event and unrelated. He did state that the lift pump was likely causing air to be in the system because it was starving the high pressure fuel pump (top side). He did say under normal circumstances the lift pump DOES expel any air in the system (when properly functioning).

I got a mile away from the repair shop and the check engine light returned (UGGGGG). I went right back to the shop and they hooked up the scanner. The code indicated "Excessive Turbo Boost". He had never seen this code before. He checked things over and said it was likely just a glitch (the turbo is operating within correct parameters). He cleared the DTC and it did not reappear when I drove it home (about 20 miles).

So, it appears that this has resolved my issues. I guess I won't be afraid to do the next fuel filter change after all lol.

I wonder if my initial issue (unable to break the fuel siphon when removing the lower filter) was also a symptom of the failing lift pump?

Not a cheap fix (final bill right at about $1400) but glad it wasn't something worse.

Thanks everyone for the input.

 

Appreciate you posting the conclusion.