Engine/Transmission (1994 - 1998) Fuel Problems, air leak, lift pump and dropping tank

[henry_md]

I've always had a small air leak in the fuel line since I bought the truck about a year ago. Since I have not pulled anything significant it was only a problem at WOT or climbing a major hill at freeway speeds. In addition, the fuel pressure gauge only read 20lbs at best at idle and would drop to 13lbs WOT when the air becomes an issue. This is a 95 12v 2500, extended cab. BTW, changing the fuel filter made no difference here.



So last week I decided to replace all the original rubber fuel hoses, filter and lift pump. And also bypass the fuel heater.

So here is the problem:

1) New lift pump is not making pressure - 5 lbs is max

2) Still have small air leak (seen in site tube). I believe the air leak is actually at the tank where it draws the fuel.



For the lift pump, I'm going to hook the feed line directly to a jug of fuel. Then I will know if the new LP is bad or if there is restriction in the line somewhere.



If the source of the air leak is at the tank cap or something inside the tank, is there an easy way to test this? What is the best solution for a cure?



Also, any great ideas on how to drop the tank? I've attempted this twice last week. The problem is the front strap. The extended cab has a two piece drive shaft and the front strap is wedged into the mounting bracket for the drive shaft. I can easily unscrew the strap and pull it away from the bolt. But that is all the movement I can manage without removing the drive shaft mounting bracket. Ideas?



Thanks,

Michael

 

[LandShark]

I did a write up here a few months ago for similar problems. Use the search function to find it and many other comments on this problem.
I have always lifted the bed rather than dropping the tank. Easier for me.
Metal lines have also been know to leak, so replacing only rubber lines is not a sure fix.

 

[gcorron]

My truck had the "bouncing" fuel guage, figured it was the sending unit. Wrong! It was the lines on top of the tank rotted out! Had to replace the entire in tank module because it was rotted in half and the guage was just flopping around in the tank. I replaced the fuel lines from the tank module to just in front of the tank with rubber, since the lines beside the tank (much like my brake line) had also rotted badly.

I did a powerpoint of the thing, if you PM me with your e-mail address, I can forward it to you, not sure if I can post a powerpoint here or not. Also, here is a picture of the top of the in tank module, what a beauty!

George

 

[JPS]

George, just sent you an e-mail. Thinking about putting rubber hose from fuel tank to life pump. jps

 

[GAmes]

When you replaced the lift pump did you check the square cut o-ring that fits the metal intake line to the top of the prefilter? Also, did you wrench down the L fitting that you had to swap from your old pump?

 

[JPS]

GAmes, New pump won't be here for a few days. Have not taken old pump off yet. Suppose Geno's would have that square cut o-ring. Guess I could spend a little with our friendly Dodge dealer. Maybe napa. Trying to get new hose from Genos on a add to order deal. Have the starter off, makes it easier to get at. Notice I said not easy, just EASIER. Have a new 2 post hoist laying out back. Getting to dam old to put it in. Guess I'll have to get some help around. Thanks for the suggestions, by the way. I really appreciate the help. This is a heck of site. Thanks everyone. Hope new pump does the trick!!! jps

 

[JPS]

Any body have a part # for that square cut "0" ring GAmes is talking about? TIA Is there a good parts book available for these older trucks? Maybe on a CD! jps

 

[gcorron]

OK, I got the powerpoint sent out, I hope! Let me know if it didn't work. I thought I would load a closer picture of the top of the tank, you can see better how bad it was. Still puzzled about the in tank module rotting inside the tank, but what are you going to do? Also, I cheated, I used my little backhoe to lift the bed, HEY, I'm old, full of Arthritis, and grumpy, what would YOU do? :-laf

George

 

[JPS]

Yes, I received the write up. Great job and very good info. I know what you mean, health wise. jps

 

[crabman]

"Work smarter, Not harder"!!
Right, gcorron?

 

[GAmes]

Any body have a part # for that square cut "0" ring GAmes is talking about? TIA Is there a good parts book available for these older trucks? Maybe on a CD! jps

I had the thread bookmarked with a picture and the part #. It was from a few years ago and this new software won't let me go there. If I can find it I'll post a link.

 

[GAmes]

OK, I found the thread. Post 19 is the pics, post 20 is the part #. https://www.turbodieselregister.com...8-Lift-pump-failure/page2&highlight=lift+pump

 

[gcorron]

"Work smarter, Not harder"!!
Right, gcorron?

That's been my motto for several years now!!!!! I've taken tanks down half full, I don't care HOW careful you are, it's gonna hurt! I like the ATV stand idea, that may work better, but considering, the backhoe was easier. Gotta admit my neighbor was more like :--)

George

 

[henry_md]

So another week has gone by and I am getting real tired of taking down and putting back the starter, lift pump and fuel tank. After replacing all the rubber fuels, I still had a small air leak in the fuel. I finally replaced the draw straw and the original metal lines on Saturday. I think that took care of the air leaks. Unfortunately, now the fuel gauge stopped working - great!

The other issue: the new lift pump will not pressurize the fuel. It simply pushes the fuel back and forth creating foam. I see this in the site glass I added. How likely is it that a new lift pump is bad right out of the box?

So I finally re-installed my old pump to make sure there was nothing wrong with the rest of the fuel system. I was able to bleed the air out of the old pump easily and start the truck. Of course, the old pump only makes 15-18# pressure and runs right out WOT or climbing a hill. Thus the need for a new lift pump.