This afternoon we were going to drive my truck over to my parents house for thanksgiving dinner. It's about mid 20's here with windchill probably in the mid teens. Anyways, i go out to start my truck to warm it up a little and it starts to crank over then it dies. It did this a handfull of times, so i tried stepping on the fuel pedal right as i was starting up and it started up. It rumbled pretty good and a bit of smoke came out of the exhaust. I figured it was just being cranky because it was cold outside. I let it run a bit then i tried to move the truck around a little so i put it in reverse, backed up 15' then put it in drive and pulled back up to the same spot in the driveway and my wife was waving her arms at me saying something was leaking on the bottom of the truck. So i put it in park and look underneath the truck and i saw diesel fuel pouring out from near where the engine & trans meet. I think it almost looked like it was pressurized and not just dripping out slowly. It poured out about a couple gallons i guess. I looked under the hood and i saw a little spatter on the starter, and the leak slowed almost to nothing on the underside in a few minutes.

I was too dressed up to crawl under the truck to get a good look at where the fuel was leaking from, but like i said it was mainly around the area where the engine & trans meet, on the drivers side, and there was a little wet spatter on top of the starter.

Any ideas on what could be the problem? I'm hoping it is something with a fuel lines (had originally planned to replace them this spring ), or do you think it could be something with one of the pumps????

Thanks,
Tim

 

The pump/fuel heater is right above the starter area. The stock fuel filter location is next the head near the firewall, above the starter towards the back of the motor.
Could be ther fuel filter or could be a line coming from the pump.

 

If you were getting squirts of fuel when the rig was being cranked, and it ran while leaking, then look to the return hose and to where it joins the steel line that returns to the tank. That is right above the starter, too.

If you spring a leak in the fuel heater the truck will not start at all as it will air lock the injection pump.

 

Both the supply and return lines are prone to failure. They both go from metal to rubber right at the bellhousing to block area. Its a PITA to get at them. The best fix is to get what is considered "marine grade fuel line" so it dosent happen again. someone here sells a kit for these trucks. If I remember correctly one is 5/16`s line and the other is 3/8`s and 3 feet each is plenty. Also Ive read many bypass the metal bellhousing section due to the difficulty of getting at it.

 

Most likely the hose in red below has failed

 

I looked under the truck this morning and i saw that one of the braided flex lines came off at the connection right under the d.side door. I am assuming it was a return line because the truck was running when it was leaking out.

Bill,

I searched a bit this morning on replacing the fuel lines. I came across a few posts of yours saying you cut the metal lines about 2' from the fuel tank and run rubber from there. Do you just cut them with a hack saw, and press a small flare on them with a flaring tool, then attach the hose with a hose clamp? Would that seal it up good enough? The 2 metal lines seem like they are the same size. Is there any way to tell which one is which just by looking at them along the frame rail?

And i called a local diesel shop (where i've ordered cummins parts from before, they service big rigs) and asked them if they carry diesel grade fuel line. They said they do and it's labeled "Fleetrite Oil & Fuel Hose 34289." It looks like it is about 1/8" or so thick and has a cloth layer in the middle. I don't think that it is the marine diesel fuel line that has been mentioned in other posts. I called all over and i can not locate that marine type of fuel line. I need to get this done by the weekend so i can get to work on monday. Will this "oil & fuel hose" work? The shop say that they use it all the time without any problems.

Thanks,
Tim

 

I think all "fuel" line is now dino diesel and gas rated. You may need special stuff for biodiesel or alcohol.
My 96's return line began to squirt where the rubber degraded, right over the bell housing, and it all leaked from the bottom of the bell housing. I did not have any 5/16 line available that night, so I cut the end off and reinstalled it. I need to get back under there and replace all of that line. It is probably additionally degraded now because I run B100 every chance I get.


Chris

 

Tim, I remove a couple of the tubing hold down bolts and use a miniature tubing cutter.
No flairs, just a hose clamp.

 

infidel is the red hose you show the delivery or return line?? I found a leak under my truck today.........

 

Hey I was looking at my fuel filter and I noticed two black wires coming from the bottom of the filter? What are they for? And how do you drain the water from the filter? My fuel leak seems to be coming from the fuel filter. The filter was loose so I gave it few more turns.



Thanks..... Dave

 

The red hose is the return line. The intake hose starts where the right side red in the diagram ends.