Archived fuel system wont prime

[Ncostello]

My truck is dead in the driveway. Changed the fuel filter with a Mopar filter yesterday. All went well. Bumper the starter 4 times, let the pump run to prime, started, ran for about 3-5 seconds, died. Will not start.



The lift pump runs, although it sounds quiet unlike the one on my ISC 330 HP firetruck. On the firetruck, you can notice when the lift pump slows down cause the air has been purged.



I even took off one of the brass plugs in the aluminum filter top to let air bleed out. No fuel ever comes out after 6 more prime attempts. I guess the lift pump wont pump. And the fuel tank does not have a cap on the roll-over valve.



I can get a new pump today for $150 but dont want to put it on and not solve the prob. How loud should the pumps be. Mine is barely audible.



I also opened the drain and about a teaspoon came out after all this. LP must have gone south. I seemed to run fine before all this.



Help and thanks.

 

[B.G. Smith]

Lift pump

The pump will run and still not pump fuel, mine did. Go for the new pump. Be aware that the pump is covered by the engine warranty of 100,000 miles. Some folks have had problems with dealers but mine was replaced under warranty at 82K. bg

 

[Steve St.Laurent]

If you've pulled one of the plugs out of the top of the fuel filter and bump the starter and can hear the lift pump run but no fuel comes out then you DEFINATELY have a bad lift pump. If you didn't hear the pump run at all then there's a possibility that it could be the wiring to the pump, the ecm, etc. But since you hear it, it should be pumping and obviously isn't.

 

[Ncostello]

Thanks a million for input. Only thing is, at 78000 miles its under warranty, but I would have to have it towed and then wait for the install. I dont have time. I hate to buy it but I just cant wait. I can install it tonight. Will cummins parts like this lift pump have its own warranty incase it is bad or goes out in 100 miles??



Plus, I bet I got air in the injector pump. It ran for 5 sec then quit. Must have emptied the lines. Hope like heck I didn't get air in it. Then its bleed injector lines. Where do you crack them at?? Had to do this on a Cat 3208 but that one was easy. This one looks different.



PS..... can I just open the canister drain valve during priming as long as my hose is above the canister level?? That should help purge air. OR should the new LP purge fine enough on its own.

 

[B.G. Smith]

Prime

I doubt that the new pump will prime since you are going to drain the line back to the tank and allow more air to enter. The best place to bleed the air is at the banjo fitting on the side of the injector pump but you need someone to bump the starter for you so you can tightren the bolt as soon as you get clear fuel, you can get the air out up through the filter like you state above by holding the drain hose above the filter and bleeding. I you have to bleed at the injectors, just loosen the nut where the line ties into the injector at the cyl. head, loosen the front three as they are easy to access. Soon as you get good flow of fuel there, tighten the nuts to 28ft. pounds. bg

 

[Ncostello]

Got the new lift pump OK. Will install the afternoon. I hope this new pump will prime even though air will get in the line between the pump and the tank. I'll try my best to bleed it out without messing with the injector pump. I'll go there as last resort.



Question 1. How do you torque the injector lines at the injectors? my torque wrench wont go over the line will it? I bet you have to have a special socket dont you?



Question 2. Have I read somewhere that many VP44 failures occur after the install of a new lift pump? Or is this failure when people do some "bombing". I cant remember.



Who knows how long this has been like this. The VP 44 must have been supplying its own fuel all this time. Im sure the previous owner has no idea. But I sure dont know how they would have got it running on the last filter change if I cant.



I'll find out in about 3 hours it all this works. Man, I just bought this truck and all this. Wasn't what I had in mind at all. But at least I had read this forum for some time prior to buying so I know what to do.



My own opinion is that the LP needs to be bigger. It just looks too small. That has to be it!

 

[B.G. Smith]

Lift pump

Yes, the VP-44 will run without the lift pump working until it loses prime. There is a socket with the side cut out and I have a set but they are not metric. Also could use a crowfoot wrench, I have those too but not metric. I use an open end metric and a calibrated right arm to get 28ft. pounds. (educated guess). Not the best in the world but if you know what the torque is supposed to be, you can be more careful and not strip the thread or leave it too loose. Have fun and don't worry too much about the VP-44, it, is probably OK. bg

 

[Ncostello]

Thanks a billion. I figured thats what I needed. An old diesel mechanic showed me how to bleed the air on injector lines on a Cat 3208 in a fire engine. I asked him about the correct torque and he just smiled. He just had the feel for tightness. It works. Thats what I was going to do. Thanks again.

 

[Ncostello]

New LP on. Truck started and runs now. Thanks everyone.

 

[RBSOB]

Way To Go Neil

Discussed, diagnosed, fixed! Not a single call to D. C. ? This seems to be a fairly common scenario... replace fuel filter and discover LP is shot. Time to consider a Fuel pressure gauge on your "new'' truck . Congrats on the quick fix. Jim G.

 

[Ncostello]

Fuel guages are in the works. Big smile on my face when it roared to life and stayed running. In fact, it started alot easier than I thought it would. Thanks again.