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!

 

Were any of your filters of the spin on type? If so ,did you fill the spin on filter with clean fuel before installing it?

If you created an air pocket that cannot get out, when you shut the engine down that air pocket will push fuel back down to the tank as the pressure is allowed to drop.
Don't know if this is the case, but we have to start somewhere.

 

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!

 

When you prime the system, a pump pumps fuel into the system and by passes when the correct pressure is achieved.. If there is air trapped in the fuel lines to the injectors. It must be allowed to get out and we usually do this by loosening the lines at the injectors one at a time while the engine is cranking., and then it starts.

Techs usually have the necessary tools to do this alone.
If the system is allowing air to get in., you would have a low power complaint.
I suspect the problem is just trapped air that cannot get out ..