I have a 98 Chevy k3500 with the 6.5l, 248,345 miles. No mods except straight 3" exhaust. I use this truck primarly for the occasional truck type chore and trailering cars to the track. This time of year it can sit for weeks between uses. It developed a fuel tank leak so I just replaced the tank. Primed the fuel filter and Ip, it fired up and ran at idle for several minutes, then died. So after some thought and reading many posts on this forum I concluded it must have air in the the fuel system. So after confirming my lift pump is working properly I tried bleeding air out by running the lp, cracking the filter, and t valve. Eventually the truck would fire and sometimes miss and chug then die. I then replaced the fuel filter and watched the lp fill the filter housing. I saw many tiny air bubbles. So I assumed the fuel lines must be sucking air as they appeared to be orginal. I have replaced the fuel lines from the tank to the lp as they are the only ones I distrubed replacing the fuel tank. (I forgot to mention I also replaced the fuel sending unit and sock). I still can not keep the truck running, I get plenty of fuel and pressure out of the air bleed at the filter and fuel at the t valve. Also when I do get the truck to fire it does not die when cracking the t valve so I am confident the lp is working. My concern is can a lp push fuel but also intoduce air into the line, and are there other areas to look for air being introduced to the system. Thank you for any advice.

The truck ran fine before the fuel tank replacement, started everytime. No issues, so I believe it has to be related to the fuel delivery or I've missed a step in purging all the air.

 

It sounds like a fuel issue. Have you considered the PMD? I have a 96 3500 crew that had some issues 4 years back and replacing the PMD did the trick for me.

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One last thought: from a guy who has his truck at the garage getting the fuel injector pump replaced: The guys at the shop told me that my lp( which was rusty in appearance) had some moisture (fuel ) below it on the rail. Anyway, they surmised that it was sucking air through a pin hole, which i think was very plausible given the appearance of the lp. Anyway, that is an idea, but what i noticed they did to try and diagnose whether or not fuel was making it through the IP, was put a clear piece of hose on the outflow of the IP. This piece of hose connects to a metal T line which goes back to the fuel tank. Anyway, mine had no fuel going through the IP, therefore they were certain that the pump had froze up and needed replaced.

 

I dont think it could be the pmd, I have owned this type of truck before and the pmd issues alway happened when the truck was running, usually at operating temp. This is a truck I purchased used and I don't know the age of the pmd but I can't even get the truck to run long enough to warm up. But I never had an issue until I replaced the tank, so I would like to rule out all possible air leaks first. I still think air is an issue because when I open the fuel filter bleed the fuel comes out strong but looks to be foaming, and I'm not sure this is normal. Thanks for the reply.

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Thanks Clkeever, That is a possibility as this truck is no show truck and has its share of rust. And my lp is rusted, alone with the brakes lines, (old fuel lines), the snow and road salt really take a toll as it gets packed up in the frame rails winter after winter. Replacing the lp will be next as I have replaced almost everything else from the filter back. But I do apperciate any more ideas and I'm going to try locate the clear fuel line to put on my Ip (i've read many posts on it) but dont know who may sell in locally.

 

Suggestion on the clear line: it wasn't like totally clear but rather the type that I've seen before that has strands of either white/blue material in it. I'm not sure what it's called but I've seen it at Menards ect. i believe that some of that hose can be used on a short term basis due to the fact that it will get broken down by the fuel. Anyway, hope ya figure it out.
ck

 

Ok, I see this post has had many views but not many suggestions, here is the latest on the problem. As I stated before, this truck was not a daily driver but very dependable and always started and ran well. I have replaced the fuel tank and sending unit, thought I purged all the air, started it up, it ran. Then died. I went through a cycle of purging and starting, running and dying. Decided to replace fuel filter, the housing was barely filled with fuel. So I thought heres the problem somehow the filter housing was vapor locked. Filled the housing with fuel via jumping the lift pump then replaced filter. Truck starts right off run good for a few minutes sputters and dies. So I replace the fuel lines supply and return thinking they may be introducing air since I moved them to replace tank. No change, old lift pump was doing the job but since I replaced everything else I decided to put new one in for good measure. Still not running, but I keep getting the truck to run after priming the fuel filter via jumping the lift pump, runs perfect for a few minutes, sputters dies, repeat. So finally I pull the fuel filter after it dies. Its nearly empty. I this normal? Based on my untrained eye the fuel enter housing outside of the filter element then flows to the injection pump through the centrally located hole in the middle of the housing. If this is correct then my problem is in the fuel filter housing. Air is being introduced and causing vapor lock in the filter. Can someone please tell me what IM forgeting, Ive replaced everything from the filter back. Is there anything I may have missed, again, new fuel tank, new fuel sending unit including sock, new fuel lines supply and return, new lift pump. Any ideas of where I'm pulling air into the fuel filter would be appreciated. Thank you.