Best way to go about making sure fuel lines are free of gunk?

[ericconn]

This weekend I am going to make sure the fuel system on my 84 6.9L is free of gunk in the tanks and the lines, probably all the way up to the injectors. The truck hasn't been run since 2005, if not longer. Sad but true.

I am replacing the rear tank because it had a hole in it at one time, plus how long it's been sitting. Once that is done, should I unscrew at the injectors and bleed the system all the way through? Or should I do it before the injection pump so nothing gets clogged in there? Or even before that? I can't remember if there's a sending unit after the tank switch, I know the 5.0L EFI fuel system a little better than this truck, and it's in another town at my mom's house.

Any help much appreciated.

 

[OLDBULL8]

Since your replacing the rear tank, no need to worry about that. Drop the front tank, dump any fuel left in there, if it's clean you can reuse the fuel, unless algea is in it. As long as you haven't started the engine before doing this, I wouldn''t be concerned about the lines, just change the filter before starting the engine. Myself, I would put about a gallon of ATF in each tank with about ten gallons of diesel in each. If all the lines from the Tanks to the injectors seem good, just start her up and let her run while you inspect all the system for leaks. After shut down, pull the filter, check how dirty it is if any, dirty, then change it. Let set for a day if you can, then start her up again, if you have a hard start, then check for air intrusion.

 

[icanfixall]

The above really sums it up. I'm not sure I would do anything differant about starting up the engine. After the filter we have a feed line to the injection pump. That line has a seal called an olive usually so hard and stuck in the brass caps. They are 5/16 in size. any injection pump repair shop will have them or typ4 aka Russ or agnem aka Mel @ Conestoga Diesel has them. Both of these guys a good members here and treat us fairly everytime. Also welcome to the forum. We have more collective experiance with these engines and trucks than any dealer anywhere. So please ask for help before turning a wrench. there are some things we can help you avoid doing uselessly.

 

[ericconn]

Guys, thanks a lot. I don't have a lot of time to wait for a whole day to pass, I'll only be working on the truck for the day and trying to get as much done as I can, so could I just pull the filter off, and just cycle some fuel out of it? I was worried about algae, but that won't be in the fuel lines after the filter because there's no air, right? I'll have some air in the lines after that, but I can bleed those. I'll have a friend helping me this weekend, but might not have a second set of hands the next time I work on it.