Engine/Transmission (1994 - 1998) Help!! Fueling Problems?!?!?!

[Mbschmidt]

My '96 2wd auto is having some serious problems with the fuel system.

The truck usually starts and runs fine, but once in a while I have this problem:

I will be running down the interstate and all of a sudden it will start to miss, sputter, shake, and lose power. This will not clear up on it's own if you keep on driving. When you pull off the road, it will idle roughly and eventually die. It will then not start unless you give it at least half throttle, and will not stay running unless you keep your foot in the throttle. If I shut the truck off and pump the primer about 20 times, the truck will start right back up and usually run fine... sometimes for days, sometimes for minutes. Usually happens at highway speeds, but I have had it happen to me in town too.

I don't know if it has any affect on it, but the sending unit in the tank must be messed up too, as it will read full when you fill it up, but will drop to empty and stay there after about 50 miles or so.

I have changed the fuel filter and cleaned out the screen (which was filthy!). I also changed the overflow valve, all to no avail, it still will do this to me.

I bought a lift pump today and am going to borrow a friends shop tomorrow to put it in. I would drop the tank too, but I cant get a sending unit until Monday, and I dont want to drop the tank twice.

Does anyone have any insight as to what is going on here? Do you think that it could be the lift pump, or am I wasting time and money? Any thoughts about the fuel tank and possibly the pick-up tube? Could the problem be something more serious even, like injectors, or God forbid, the injection pump?

Please help, I am about at my wit's end!

 

[EKlem]

Are these sypmtoms related to how much fuel is in the tank? If you refill, do they go away?

I would doubt that a faulty lift pump would cause problems like this. It sounds like you are introducing air into your fuel lines or not sending fuel to all of your injectors.

 

[Mbschmidt]

seems to happen most often when the tank has had at least a quarter of the fuel run out of it, and yes, many times the problem clears up once the tank is filled. What do you think might be the cause then?

 

[KAlder]

If the pre-filter was dirty, I could only guess what is in your tank. Sounds more like you have something plugging your p/u tube.

 

[Missouri Mule]

I have read where the pickup tube has had a whole in it (rubbed) and caused this type of problem.

 

[DSeamans]

It does sound like a pinhole in the pickup tube and/or clogged screen. Some stores sell a combined unit with the sending unit, pickup tube all together. Unfortunately, neither napa nor autozone list one for these. When you drop the tank, look for a waxy buildup on the prefilter. That alone could cause this. If its there, look for goo buildup in the tank. If its not there, try to pressurise the line and look for a leak.

Good luck,



Dave

 

[EKlem]

seems to happen most often when the tank has had at least a quarter of the fuel run out of it, and yes, many times the problem clears up once the tank is filled. What do you think might be the cause then?

As stated above, this can be symptom of a problem with the pickup tube inside the tank. What happens is that it develops a small hole in it which is not a problem if it is covered by diesel. However, once the level in the tank gets low enough, you will start sucking air. Even a tiny hole can cause major problems. If you can pinpoint it to always happening at about a certain level in the tank, this is most likely your problem.



Good luck.

 

[JGK]

When it is experiencing these problems, before you shut off the key, reach in and make sure your fuel shutoff solenoid is fully up. It may be that it's sagging a little and restricting fuel flow.



-Jay

 

[Joe G.]

Email me at -- email address removed -- for my write up on the 12 valve fuel supply system, how it works and how to fix it.

 

[CEdwards]

Had the exact same thing happen to me on my first dodge. I replaced the pickup in the tank, all fuel lines everywhere, overflow valve. Always had good pressure when it would cut out. I would hear a ticking sound. I thought it was only when tank was low but then it did it with a full tank. I finally sold the truck and got a different one. Seemed to happen most when traveling down the highway or when it was hot out, but not always. Are there any other symptoms like blue smoke, ticking sound, poor mileage lately? If you follow joe g. 's write up you can eliminate all fuel delivery problems. I am in the process of doing the same to my current truck. When I was having problems I was incredibly frustrated and I could only find a few cases of these symptoms when searching threads. No one on here seamed to experience this same problem and alot of posts never followed up with a solution. Hang in there and start eliminating fuel delivery problems first, then see where you are at. Follow joes write up and eliminate every possibility one by one and hopefully you will find the problem. If you find something please post back for everyone else to see.

 

[Mbschmidt]

well, since i started this thread, i haven't done a thing to my truck except for i ran a bottle of lucas fuel treatment thru it, and i have not had a repeat of those symptoms as yet. i bought a new lift pump and was going to change it, but i had some transmission line issues so i decided to wait a week, and since it stopped i am just going to let it ride for a while.