First post for a long time lurker (thanks for all the past help and entertainment).

I've had my truck for about 6yrs now and I've been down for the last 3wks.
This started by changing out cracked fuel hoses (supply and returns).

Long story short, I shut the truck down when I noticed the leaks, changed out the fuel lines, then had a heck of a time getting it started. The truck sat for about 1.5wks through rainy weather. Went through every bleeding proceedure I could come across. Finaly take the filter off and it wasn't full. Filled it, then truck fires within 30 sec. runs rough 30 sec. idles smoothly for 3min, then dies. Refill the fuel filter, go through the same sequence. Put a new lift pump in from cummins, still have the same prob. pull the supply line off the tank and disconnect near the filter and blew air through to clear line, seemed fine. Put back together, started again with a fresh filter fill-up. Dies again. Even tried the 10-15psi in the tank to push fuel up to the pump. I can keep the truck going a little bit longer than the usual 3 min interval, but it eventually dies again. Some suggestions would be appreciated. I haven't pulled the return line from the tank for lack of a tool to get the fitting off, hence trying to avoid dropping the tank (about 3/8 full and no way to drain).

Sorry for the long post.

 

It seems obvious that your lift pump is not working. Have you tried taking the input hose off the filter and cycling the pump? I wouldn't start the engine until you get the lift pump working. You should consider moving the lift pump back on the frame rail. ( Vulcan kit ) Can you hear the pump run? Maybe it's an electrical fault.

Keep us informed of what you are doing, 20.000 heads are better than one.

 

I put a new one in. When there is good fuel getting to the lift
pump (pressurized tank) I can manually run it and get a pretty good surge of fuel out where the filter is (filter removed while I'm pumping to check).

 

....I think you are on the 24 valve page.

 

Not filling the filter would make me to start looking in the fuel inlet system. There is also a screen in the fuel heater that some have found clogged. Personally I've never run into a prob with it, but it is a possibility. I also wonder how it would act with a full tank. Some have reported finding a mounting screw on the fuel module in the tank that comes in contact with the plastic line eventually rubbing a hole in it causing air to enter the system. Full tank it will run fine, but as soon as the fuel falls below that level you start getting air. You can take the fuel tank and inlet out of the game and use a 3 gallon gas can to substitute as a fuel tank. Just route two hoses (inlet and return) into it and go from there.

 

The tank was my last resort so I just dropped it a few minutes ago, it was the last thing I wanted to do. I pulled the Module from the tank and it doesn't look servicable really. At this point I think I will try the seperate tank idea. I did replace the pre filter/heater screen while I had the started out. After 6 years there wasn't anything but a bit of black crud built up around the sheetmetal nut. I did see some screws that could cause the problem you mentioned, but I haven't looked that closely. (Just went outside) There are four screws that hold two halves of the tank module together (they slide relative to each other). There is a bend in the supply line that rubs right on the point of the screw. I could feel a burr on the tube. I'll inspect further and let everyone know for future reference.

 

Just saw this post. Did you ever manually pump the liftpump with the fuel filter off? This would prove the liftpump was working. I read somewhere a few years ago it was possible to misinstall the 12v liftpump. Might try a search?

 

Yes, I did run the LP manually to see what I was getting out. Seems to me, that it is a pretty good shot of fuel as long as there was fuel on the supply side of the LP. I also put my hand on the pump when the truck was running to make sure I could feel it pumping (not the safest thing to do, make sure the shirt is tight on your body before getting anywhere near that fan shroud).
It had a good surge to it, but maybe only 3/4 to 2/3rds the stroke you could push by hand. About the only thing I see you could do is put the gaskets in the wrong order with the pre-strainer housing. I will search the LP install though.

I don't have the supplies I need to set up a seperate tank, so I'll have to run down some more fuel line and fittings and try that tomorrow night.

 

I tried the seperate tank idea. I used 3gal in a plastic can. Still had a heck of a time getting it going. Finally started pressurizing the 3gal can, took about three more fuel filter fillings to run the air out of the supply line. Then the truck started running well for at least 5 min. Then realized the return line was filling my smaller can. Shut the truck down, broke the seal for pressurizing the supply can and put the return in there. Started the truck up without pressurizing the supply. It made it about 6-7min before it died in the usuall manner of loosing fuel.

My question. I have a truck I can't run without pressurizing the supply tank. The tank is sitting on the ground so the lift pump has to pull fuel an extra 1- 1.5ft more than when the tank is in the frame. Should the LP be able to pull fuel without a presurized tank? Before I tried all this I took the fuel lines off at the engine (supply and return) and blew them out, seemed like it was fairly restricted. I'm having a hard time understanding why I didn't have trouble long before I noticed the lines leaking. Can some unknown force cause my fuel lines to clog while it sat for 2wks? My patience is comming to an end with this. I can't even begin to consider the tank module yet. I don't want to know what the fuel lines cost from Dodge, maybe they are the next logical step?

 

Have you checked the fuel pressure? Maybe a bad overflow valve. Or, I have heard of the fuel heater leaking air into the system around the electrical connector as well.

 

Well with you not having the special tools for the fuel psi test I would get it running and use a pair of pliers to restrict the return flow some. I could be a overflow valve issue as bmoeller suggested though I'm not certain they can fail to a point where they would cause a no run condition. Any chance the valve has ever been changed? The originals were painted black with the pump. You may be due anyways.

 

Try this website:

http://www.dodgeram.org/tech/dsl/tro...2v_trouble.htm


Under "Rough Idle and low power" is the procedure for Overflow Valve testing

 

Thanks for the help. It just took me a long time to trouble shoot. It turned out to be the Steel Braided fuel Supply line letting air in the system. I have
currently bypassed the entire line and all is well, but I intend to replace it with the original OEM part so it is as designed. I didn't want to think it was this line because the truck ran fine, I shut it down until I could get to replacing the return line that was leaking. I may have bent and cracked the
hard line too during the rubber line replacement work.

Thanks for the suggestions on the overflow valve, but it was replaced a few
months ago when I first put the TST plate in.

I also screwed up my fuel gauge while I had it out, now I have to drop the tank again and fix the pivot I guess.

 

Thanks for the update!! always good to have closure.

 

Quote:

I may have bent and cracked the hard line too during the rubber line replacement work.

This is the very reason I no longer replace just the short hoses but rather run new hose all the way from the engine to tank. The metal lines on top of the bell housing have a tendency to crack where the bolt down tab is welded on even without your help.
Besides that running hose all the way is a much easier job, well worth the added cost of longer hose.