I have an 88 E350 With a 460 EFI . Problem is there fuel is comming out of the ecs cannister . It has the dual cannister set up fuel comes out of the rear one after the engine starts. I have never seen this before. Anyone an idea what would cause this ?

 

My first guess is too much gas. Have you checked fuel pressure? I'm not sure how the canister is hooked in on the FI units. Is the a check valve? My guess is a FPR or a check valve bad. On a carbed unit the canisters are hooked to the fuel bowls, I have seen it with these when a float bad or too high or a leaky needle & seat.

 

The EFI return line from fuel rails goes into the upper connection,then there is a connection below that one that goes to the fuel tanks,it also has a larger line running to the second cannister.
guess I will try to find any check valves or solenoids in the fuel circuit.