97 dual tank issue... Maybe...????

[Dieselmaster]

Hey guys... my nephew has a 97 F250 PS with the dual tanks...

He was asking me last night if there was something that would help him when switching tanks to eliminate the lag time of one to two minutes..

I wasn't feeling well and had lost my voice last night so I didn't go into to too many details but from what I gather, when he drains a tank and switches over to the new tank it takes up to a minute or so before the motor sees the fuel..... He says everything on the dash shows the up instantly but if your going down the highway, it takes a while for the fuel to get up to the engine..

I didn't ask last night if he was running the tank out of fuel and then switching it or if this did it everytime he switched his tank.... knowing him the way I do, I can safely assume that this is happening everytime he switches tanks and he is doing it well before he actually runs out of fuel.

He said he has checked everything mechanical and electrical and pressure wise he has plenty... This only happens when switching tanks and only for the 1-2 minutes after the switch... once that time span is over it runs like it's suppossed to...

Anyone have any ideas or is this a known problem with a common fix?

Sorry I didn't do a search first... it's early morning and I am trying ot get this off before I have to take my daughter to school and be to work....

 

[Double-S-Diesel]

does it do it on just one tank, or on both tanks?
the fact that the guage is responding makes me think the valve is moving, if the switch valve dont move , the guage doesnt move.
other than that he is running the tank dry or to the point of sputter and getting air in.

 

[Mike]

other than that he is running the tank dry or to the point of sputter and getting air in.

bingo!

Tell him to switch his tank 1 gallon sooner, right now his injectors are HATING him for not doing it sooner and he will eventually pay the price.

 

[Dieselmaster]

Yeah, I never did get the story of if he was running it dry... My first thought after I got off the phone with him was that if he's running it dry then he's going to have to wait for the line to purge of air...

I will have to find out more to see if it happens when switching from tank to tank..... or just one of the tanks does it .... or if it happens anytime he switches tanks no matter what the fuel level is.

I will give him a call in a bit.