pump problem

[mudgeek]

Hello, I have a '93 w250 ext cab which has been a great ,reliable truck. A couple of years ago it started to ,very slowly ,develop a fuel delivery problem. Eventualy I realised that the main fuel injection pump had a leak. I had the pump resealed and tested by a reputable shop here in Denver. After the pump was reinstaled(by the local dodge dealer ship) the air in the fuel problem is worse than before. The symptoms are that I bleed the injectors then the truck will run for a while becoming more and more rough until it dies then wont start again untill I bleed the injectors again. Could any one suggest a systematic approach to tracking down where the air is geting into the system or what else I might try . thanks so much

 

[Kirwin]

Most likely not a pump problem

I would look for a leak in the pump fuel supply line including the fuel filter head and heater assembly. Most likely your just getting too much entrained air for the self venting fuel system to get rid of hence the injector lines eventually become air bound.

 

[cerberusiam]

Check your fuel pressure first to make sure you don't have a dying LP. There is a plug between the pump and the filter housing that will allow seeing what is happening.



The heater assembly is suspect after so many years. A more frequent event is the lines from the tank the LP either rusting thru or cracking and allowing air into the system.



The tank cannister itself can be a problem if the pick-up tube is loose or cracked.



That should keep you busy for a few days, good luck.

 

[JLEONARD]

You can pressurize the fuel tank thru the filler. Use an air gun and seal it with a rag. You only need a few psi in the tank to make a leak show.

That will get you to the lift pump.

Lift pumps are relatively cheap. If you still have the oem it would be wise just to change it anyway as part of this excersize.

Many of us have had lift pumps die... and we all go thru the same pains.

 

[mudgeek]

Thanks for the replies felas. I've already replaced the LP but will try some of the other sugestions tomorow. Cheers

 

[mudgeek]

Is the heater assembly refered to above on top of the fuel filter? I have the repair book and just want to confirm we're talking about the same thing . Thanks

 

[cerberusiam]

Above the filter, it unscrews using the filter thread stud.

 

[HHhuntitall]

I've seen several that have done this. My Ford (with Cummins) is one. The rubber line from the frame to engine had dry rotted and cracked, allowing the pump to suck air, until it lost prime... ... sounds like your problem..... like Cerberusiam said, that's where I'd start.

 

[mudgeek]

OK so I'm still trying to work trough my air in the fuel system issue. Thanks to you guy's advice I looked at the fuel heater and low and behold it was actually loose . The seal however appeared to be in fine shape. I reasembled everything, tightend it all up and presto no longer leaking. But still geting air in the system ! Don't know if this is a possibility but when I fill the fuel tank there is a bit of a leak from the pipe/hose to the fuel tank could this be the problem ? Sorry to be so thick but I'm just not 100% sure how the fuel system works . Thanks

 

[mudgeek]

So the saga continues . Injection pump was leaking, got it fixed . Fuel heater was leaking , fixed it . Problem persisted . Finaly traced this to the fuel line from tank to LP. I removed it from the LP and blew into it no bubbling in fuel tank . Did the same thing with the return line and got lots o' bubbling. Now my question ,I cant for the life of me get the bloody " quick disconect" fittings off the tank:{ am I probably going to have to drop the fuel tank anyway ? The truck has about 140000 miles on it and I've run about 20000 miles of B100 bio through it . Do I just go ahead and drop the tank or has anyone got a good trick for getting the "quick" disconects to disconect, you know, quickly ? Cheers

 

[Paychk]

I think the tank uses this style, see attachment

 

[mudgeek]

Thats what it shows in my manual too, but it's not what's on the truck. These have two tabs which you pinch together then slide the thing appart. got them off the LP no problem just can't get them off the tank . It's kind of a restricted space.

 

[HHhuntitall]

You should be able to lower the tank a little to get access. Try that, and see if you can get in from the outside of the frame between the bed and frame, reaching over the frame. There's quite a bit of give in the fuel lines, and they're somewhat forgiving. A good transmission jack or floor jack helps a lot. If you have the tabs pinched down, they should come apart. The o-rings may be stuck and need a little "persuasion. " Don't forget to check those o-rings when it comes apart.

 

[Paychk]

With some more thought on this, would it help to remove all the bed bolts except the last set, then jack up the front end of the bed to get more clearance?

Might need to be careful of the fuel filler neck

 

[MMeier]

Thats what it shows in my manual too, but it's not what's on the truck. These have two tabs which you pinch together then slide the thing appart. got them off the LP no problem just can't get them off the tank . It's kind of a restricted space.

How are you pinching those tabs ... inside or outside the connector itself ? Seems weird at first but try this, pinch the tabs on the outside while pushing the line inwards then pull the line off. There is a pic on here somewhere, I'll see if I can find it . First time I tried to do this I was pinching them inside the connector and got nowhere !!#@$%!

 

[ENafziger]

I had the pump resealed and tested by a reputable shop here in Denver.

Just out of curiousity, it wasn't Progressive Diesel in Englewood, CO was it?

--Eric

 

[mudgeek]

It was central motive power . goin' to give the lines another go this morning.

 

[ChrisWilliams]

I pulled the bed with a motor hoist, then have full access to the lines and tank module. Could use two people to handle the bed though. Remember, there is a line in the tank from the fitting down to the pickup.