88 f250 losing its prime

[Joe cregan]

Have a 88 f250 with non turbo 7.3. Truck is losing its prime. So far I have changed the fuel pump and fuel filter and fuel filter head. Both tanks are full. Gauge in the front tank does not work n gauge in the rear tank does work. Could it be the fuel tank selector valve causing it to lose it' prime? Also the truck blows alot of white smoke at start up. Smoke continues after warm up but thins out. Thinking it' sucking air in some where. Any ideas would be appreciated.

 

[Brandon Crislip]

Check lift pump for leak/wetness

 

[Dieselcrawler]

Are all the returns dry?

 

[Joe cregan]

Lift pump is brand new n dry. Just put it on last week. Old lift pump was leaking. Return lines are all dry

 

[Thewespaul]

Did you replace the soft line at the frame where it connects to the pump? I like to add a check valve there, helps trucks hold prime. Probably pulling from the selector valve if that line is new

 

[Joe cregan]

Did not change the soft line from the hard line to the pump. Probably be trying that next. Have a part number on the check valve? If none of this works i will be doing the selector valve next.

 

[Thewespaul]

Nope just a generic check valve that’s safe for fuel, pick it up online or at your parts store

 

[SethB]

Do your glow plugs work?
I also had a similar problem, I replaced my glow plugs and it starts right up.
I can tell you a way to test i you would like.

 

[Joe cregan]

As far as I know they are all working. Can still get the truck to start in cold weather. Just thinking the air problem due to the white smoke n I get air coming from the Schrader valve while the truck is running.

 

[Joe cregan]

Changed out the soft line from the fuel line on the frame rail to the pump. Still have the same problem.

 

[Joe cregan]

No longer losing its prime. Still having issues with alot of white smoke at start up n smoke thins out after warm up but still has white smoke. So far I have changed the soft line to the pump, fuel pump, fuel filter, filter head and injectors.