I have the above van with a 35 gallon fuel tank. When it gets down to about 20 gallons of gas in the tank it starts having problems causing engine codes and starts shaking really bad. After I fill it full with gas it runs fine. Is this the fuel pump? I have changed almost everything the codes spits out.

The codes

general misfire
misfire in #1
misfire in #2 (sometimes)
misfire in #3 (sometimes)
O2 Sensors bad

Here is what I have done

complete tune up
changed both O2 sensors
changed wiring under the car(dealship) It keep on blowing the fuel Pump fuse

My mechienic says

it needs a valve job

dealership

tells me to bring it at about half tank for they can look at

I do not think it is the valves. Would it do it all the time?

Thanks for the help

The van has about 125,000 miles if this makes a difference.

 

Yes, the fuel pump is failing. It's a classic sign of pump failure if the engine runs good above a half tank but not below.

 

2 days ago I realized my fuel pump is probably causing the problems that I have been having. I have a 96 B250, when I get to a quarter tank the van starts shaking like crazy, backfires when I really gun it. I only get codes for misfires, cylinder 1, 2, 3, and sometimes 4. I just realized that it always happens when I get to a quarter tank of gas.
The first time this happened the brake booster went at the same time, so that threw me off looking for a vacuum leak or something more like that.
I wonder how long it will run if I just keep it above a quarter tank though?

 

It is more likely just water in the gas tank from condensation and cheap fuel.

Get a couple of can of "Heat" or similar to get rid of the water. I had the same problem.

 

Been there, done that with my van: same year with 5.2(318)
I have only found the solution once in a 6 month on-going search.

It's not the valves or the fuel pump. It's the fuel filter.
It all starts acting up just before a 1/4 tank and progresses over time to 1/2 tank. It does not progress past this. The reason for this is the fuel filter is at the bottom of the fuel pump in the tank. The filter is at the base of a sleeve that shrouds the pump but the sleeve only rises to the 1/2 tank level. Once the filter get completely clogged, the only fuel that can get to the pump is that which dumps in from the top of the open sleeve.

So, drop the tank, remove the pump from the tank and replace the $35 filter.
ALSO, buy a new plastic clip for the fuel line. Its a cheap piece of $#!* that will stall your job until you get one. It's brittle being that old.

I still have the van and it will run fuel to the bottom now although I don't recommend running the tank that low. The fuel is ment to keep the pump cooled.

MOPAR engineering boys...put the fuel filter in the bottom of the tank!

 

I concur.

 

What you are referring to is NOT the fuel filter but the fuel screen. Yes is does filter SOME things before the fuel reaches the pump and the filter AFTER the pump. And yes it can become clogged from dirty fuel. And yes it may clogged over time leaving the only available fuel coming over the pump module sleeve.

The filter on these Magnum engine series vans are on top of the fuel pump module (the big round silver thing). But the pump module ALSO houses the anti flow back valve (designed to keep fuel pressure in the lines while the engine is not running), the fuel level sender unit, and the fuel pressure regulator.

The down side to replacing just the screen is that all these other components have been in the tank for how many miles? These other parts also wear out. So you may save a few dollars here and just replace the screen also know as a Fuel Pump Sock, but how long before you have to pull the tank down and still replace the pump module?

I personally recommend replacing the whole pump module and be done with it. And yes keeping the fuel level over 1/2 tank will help the pump motor to last much longer.

Side note: If you question whether you are getting clean fuel from your favorite retailer then buy or use a clean gas can and look into the can after you have bought some fuel and let it set for an hour or longer. If you see junk in the gas can then I would find a different place to buy fuel. Also if the gasoline is not see through like clean water (if it looks frosty/milky) then it is not good fuel.

 

Hat's off. Precisely so.
Thank you for enlightening the unenlightened.

 

this is the exact issue i am having! same thing.... multpile cylinder misfires, at 1/2 or less tank....

 

96 dodge maxi van..cut hole in the floor above gas tank..

in process of removing pump assembly from the tank...

detached the fuel line okay clip still 100%

how do I detach the electrical connector.. I don't want to break anything..

cutting the hole was a delicate operation.. did not make any holes in the plastic tank.... full access now available... took a couple of hours.. going slow..

I can take pictures.. how to post? them here!