86 F250 w/6.9 IDI. When I changed the fuel filter I knew I would get air in the system. After replacing all the return lines as well as the lift pump I still can not start truck cold with out help. No, I do not use the glow plugs when using either. After truck is started, she runs very well with just a hint of blue/charcoal grey smoke under heavy throttle. I also have nothing but a trickle of fuel coming out of the return lines, I could almost run without them attached from the amount of fuel that's coming out of them. A new problem that just arose is sluggish throttle response from idle. There is no snap to the throttle as there used to be. I am not a newbie at working on vehicles but this is my first diesel so any and all help would be most appreciated.

 

Come on people, isn't there anyone who has had the same problems. If there is a post with similar question, let me know please.

 

Since you have replaced the lift pump and filter, have you made sure that all the fittings are tight. Also check to see if you are getting air in somewhere down the line coming from the tank. I would check to see if maybe a line has collapsed somewhere, causing fuel delivery restriction. I have also heard of the pick-up tube in the tank can come apart, causing fuel issues. Check the simple stuff 1st, always works for me.

 

My guess is glow plug system not working. With air intrusion, usually the truck will start and then die in a few seconds and take some cranking to restart.

 

ok. I replaced the rubber fuel line coming from the tank(s) to the lift pump as they were in rough shape. The fittings have all new and very tight spring hose clamps. The glow plugs were replaced last summer with BERU ZD1A GP's and they are on a manual momentary switch that I held for 6-7 seconds when she was running right. There is a nipple on the IP side of the filter that I attached a clear long tube going to a clear pitcher. After letting the truck run awhile I noticed no more air bubbles but I still have no fuel to speak of in the return lines at the injectors as the tubing there is clear also and still I have a very, very, very sluggish throttle and if I try to snap the throttle she will try to die on me.

Back during the filter change I even blew thru the return lines back to the tank to make sure they were clear. I took the return connection from the top of the IP and made sure the fuel shutoff valve was clear, which it was to no avail, still no return fuel and no snappy throttle. Is there anything serviceable on top of the IP such as where the FSS is located that I can remove and check to see if there is an obstruction?

This truck has 416,000+ miles on her and the last owner stated the engine was gone thru at 350,000. Since I have had it she has ran great except for the present which all happened after changing the fuel filter. I am about to be bald trying to find this gremlin as this is my only transportation. This is how I carry my daughter's 300lb electric wheelchair. Thanks for the suggestions.

 

well if it is running but not very well now i would say it may have to do with the lift pump not pumping the proper amount. i always prefill my fuel filters with diesel kleen and slap them right back on she fires off no problem at all like i never even took the filter off. defiantly sounds like a pump to me if she's now firing but running like its fuel starved

 

Just to see what happens if your not against it put an electric pump on alot of people in here have there opinions about them I know mine is over 3 years old and other than I had issues with the power supply to it (now it's on a toggle switch) it has always worked and I have always had plenty of fuel and as much power as I needed (till I fried headgaskets and a couple valves, it was my fault though running her hard with no pyro) but I personally prefer the e-pump because of the ease of either turning the key forward or flipping the switch letting it sit while I warm up the glow plugs and the fuel system being primed for me when I first turn the key (I always have had drain back issues with my ol girl

 

I am not opposed to trying anything at this point. Whet e pump do you recommend? I have had one person, not on here, thinks it is my IP. Stating that maybe the transfer pump is not building enough pressure. Have you ever heard of that situation?

 

If you don't have fuel at the injection pump it can't push fuel into the injectors mine is just one off the shelf from advanced auto parts but I have heard good and bad things just make sure you don't get one that has above 6-7 psi because if you go higher than that you can blow out the seals in your ip and I would try the e-pump before replacing the ip

Forgot to mention make sure the e-pump is for diesels if you don't it will wear faster and you get the e-pump it's best to bypass the lift pump because if you don't the lift pump can lose its seals and fill the engine with diesel fuel... You can for a short period of time run the lift pump dry but don't do it for long you can use rubber hose and fill the hose with oil and let the lift pump pump into itself or use a block off plate for the hole

 

So if i get a 3-5psi epump (30gph) and run it right outside the tank, it will blow my liftpump??

 

Will be ordering one online as the prices out here on the island are sinful at best. Will let you know if that fixes my problem. Thanks for the advice.

 

It could blow a hole in the diaphram and dump diesel into the crank case

 

(i planned on using the epump to prime before starting not all the time) if i bypass the liftpump wouldnt i have to use the epum all the time?

 

Yes but if you only use it to prime the system you should be ok my truck from the po was ran into the the lp but I could feel a power difference with my e-pump off but it could just be my lp is worn

 

Has anybody every heard of the transfer pump going out on the IP. Is there a way of testing if the transfer pump is at the right pressure. I read elsewhere that the transfer pump should have a pressure between 58 and 102 psi from idle to 2000 rpm. I am not sure if this would be creating my problem but while im waiting on my e-pump to get here thought I would get rid of any doubt and test the transfer pump pressure if I knew the steps.