Newbie Fuel System Issues

[Gamble]

I appreciate all the help. If the kids/wife let me I will try to drop the tank and check all the fuel lines this weekend. If that doesn’t do it, new fuel pump is next it would seem based on the TMs and the expected flow rate.

Those vent lines are not your issue. They are cut when they demil the fording capability from the truck. Mine has the exact same thing. I too saw loose lines and said wtf. Yep, just secure them and dont worry about them for now.

Did you address the fuel check valves at the rear right of your truck? Get under the truck on the right side and locate your fuel tank if you dont have an access panel in the bed. Follow the lines (flexible rubber lines not the hard fuel lines attached to the body) from the fuel tank that hug the right side of the frame about 3/4 the length of the truck back on the right (passenger) side. You will see two brass fittings. Those are likely the culprit. They are an absolute joy to reach in and get out You also need to take a look at that fuel pump and maybe replace it. They are cheap as far as hmmwvs go, only $35 bucks or so.

 

[AtlantaSBR]

Those vent lines are not your issue. They are cut when they demil the fording capability from the truck. Mine has the exact same thing. I too saw loose lines and said wtf. Yep, just secure them and dont worry about them for now.

Did you address the fuel check valves at the rear right of your truck? Get under the truck on the right side and locate your fuel tank if you dont have an access panel in the bed. Follow the lines (flexible rubber lines not the hard fuel lines attached to the body) from the fuel tank that hug the right side of the frame about 3/4 the length of the truck back on the right (passenger) side. You will see two brass fittings. Those are likely the culprit. They are an absolute joy to reach in and get out You also need to take a look at that fuel pump and maybe replace it. They are cheap as far as hmmwvs go, only $35 bucks or so.

That is this weekends project. Dropping everything potentially and going through it again

I appreciate the help!

 

[AtlantaSBR]

With 3 kids under the age of 6 last weekend was finally the time to drop the fuel tank, check lines and replace the fuel pump. But later than I planned but oh well.

Fuel tank was dirty and the baffle was no longer connected to the bottom of the tank. Beginning to wonder if a floating baffle was the cause rather than the dirt or check valves.

Got it all cleaned out and used some JB MarineWeld to epoxy the baffle back to the bottom of the fuel tank. Cure time moves me back to later tonight for my first attempted start up.

@Retiredwarhorses have you seen baffles come lose and cause fueling issues?? Hoping that was the cause at the end of the day. Either way the fuel system should be good until the IP now.

 

[AtlantaSBR]

Fired it up last night and idled rough for a couple seconds then smoothed out and was idling fine in the driveway for 10 min. Decided to take it on a drive around the block and Atlanta's fantastic roads coupled with some hills might have killed my epoxy fix.

Hit a couple speed bumps and up a hill and it stalled out. Fired right back up again and was able to make it home but something is still going on. Going to drain the couple gallons of diesel I put in and see if the baffle is floating around again in the tank. If so, might try another fix with some more prep (sanding, etc) before the epoxy goes down and if that won't hold time for a new tank.

 

[Retiredwarhorses]

With 3 kids under the age of 6 last weekend was finally the time to drop the fuel tank, check lines and replace the fuel pump. But later than I planned but oh well.

Fuel tank was dirty and the baffle was no longer connected to the bottom of the tank. Beginning to wonder if a floating baffle was the cause rather than the dirt or check valves.

Got it all cleaned out and used some JB MarineWeld to epoxy the baffle back to the bottom of the fuel tank. Cure time moves me back to later tonight for my first attempted start up.

@Retiredwarhorses have you seen baffles come lose and cause fueling issues?? Hoping that was the cause at the end of the day. Either way the fuel system should be good until the IP now.

I would have replaced the tank.....

 

[AtlantaSBR]

I would have replaced the tank.....

New tank is coming next week it seems. Have you seem similar issues before? Stalling out due to loose baffles?

 

[Retiredwarhorses]

No, but be sure to delete the check valves, they are problematic

 

[AtlantaSBR]

No, but be sure to delete the check valves, they are problematic

Ok, I will yank those out when I drop the tank again. They seem to be functioning just fine now but I have no way to test what the resistance is other than shooting a little compressed air through.

 

[AtlantaSBR]

Swapped in the new fuel tank with all fresh gaskets, removed the check valves, and replaced the rubber line connecting the hard line to the fuel pump.

My truck is back to normal! Was able to take the doors off and take my two oldest girls for a spin in the afternoon to get some diesel and pick up dinner.