Hi brand new to the forum it looks like great resource! My problem is the truck recently began to run rough and not want to idle. I replaced the fuel filter/water separator, no help. It seems like air is getting into the fuel system. I replaced the soft fuel hose that goes between the end of the hard line and the fuel pump. That helped, but It's still running rough with allot of white smoke. also when I remove the fuel filter it's only half full, so air is getting in there somewhere. I inspected the all the fuel lines from the engine back to both tanks and don't see any obvious leaks. any help would be greatly appreciated

 

It sounds like your fuel return lines are letting air into the system. They are the rubber lines between the injectors. To fix, you need to replace the lines, plastic Ts that install on the injectors, and the O rings that seal the T to the injectors.

Usually this only affects the truck when it start up as most leaks are very small and take a long time for the fuel to drain back into the tank. Check for leaking fuel around the injectors.

 

hawaiicruz welcome to FTE and the idi forum!!!!
the problem is more than likely return lines the soft lines between the injectors Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder - FORD 6.9L - 7.3L :: INSTALLATION KITS :: 83-89 6.9L/7.3L Injector Installation Kit does the truck have a knock or is the white smoke intermittent?

 

Also I would be inclined to check the flow from the lift pump. Should be, I think, 1/3 pint from the shraeder valve for 10sec cranking.

 

Thanks for the quick replies. the white smoke is pretty much all the time, when I first got the truck it used to smoke allot on startup but would go away after driving it a half mile or so. I have plenty of fuel coming from the shreader valve, so it seems like the lift pump is ok. all of the airlines around the injectors look ok. they look fairly new. but when I was inspecting the air return yesterday I did notice that the insulation around it, where it goes behind the exhaust manifold was old and coming apart. the line seems fine though. I will have to check that more closely
Bear with me. I have a fair amount of experience with gas engines but I'm new to diesels. I'm giving myself a crash course as I go

 

how much fuel is in the tank?? these older trucks are known to have the fuel pickup in the tank crack and start to suck air at around 1/4 tank.

also, do you have a F-350, or a F-superduty??
there is no such animal as a 89 F-450

 

F Super Duty. I will change post title. Yes, the fuel is low in both tanks I will try that next.

 

it may just be as simple as low fuel.

the reason i asked is that the first year for the F-450 was 1999. if you go into a parts house looking for parts for a 89 F-450, they will look at you like you have 4 heads because the computer will not list it.

but it will list the 89 F-superduty.

 

F-superduty = f450
technically speaking.despite what ford chose to call 'em.

you say tomato,i say tomahto

edit.yeah ford went on crack in '99.
good point! don't confuse the parts guys.but we know what your saying.

 

Yes that was it! I never had that problem before but rear fuel guage doesn't work, and I guess I never ran the front below 1/4 before. Funny, it happened right when it got to 1/4. Thank you very much