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I don't use my front tank often but I get home today,smell raw gas look at gas coming out of filler door.tank is about 1/2,and rear is just below 1/2.I just looked again and its starting to seep out of front filler door again.how do I fix this issue.thanks all
The front fuel tank Fuel Delivery Module (FDM) has a bad shuttle valve which is allowing the return fuel from the rear tank to fill the front tank. A VERY common problem on this vintage truck. Search on crossflow in this forum.....
If the fuel gauge is reading half full then you also have a bad fuel sending unit and/or float. Another very common problem.
Best bet, replace the entire front Fuel Delivery Module (FDM). Then wait for the rear one to do the same thing.
I use rear tank mostly due to what I belive is bad front pump.it'll go great down road...take off/acceleration is different story.so I'm going to call parts house it'll be front tank fdm?that's the one filling up.and is it ok to drive it?
I called parts house.motorcraft $400.I almosted peed on myself.they have a carter at $159.they aren't sure if it comes with fdm.but it says motorcraft has,pump strainer fdm gasket sending unit etc.does anyone happen to have a pic of complete unit so I know what I'm looking at at parts house?thanks all for your help
Check the relay Mabey it's getting hot and sticking. What I don't understand if both tanks are half full why would it spit fuel from front unless gauge is bad and tank is really full. I would stick both tanks just to confirm the level of fuel you got in them. then swap relay just to eliminate it. Its alot cheaper than the FDM. would also check venting might be building pressure in the tank. Sometimes when I shut down my 460 and walk by the back of the truck (dual tanks also) I get a strong smell of gas.
I did make one assumption here....the OP's truck is 1990 or newer. 1984 -1989 model dual tank trucks used a three pump system with a dual function reservoir to switch between tanks. If this is the case the reservoir is most likely bad. They can be disassembled and potentially repaired.
Regardless the previous post with the theory of a bad relay is not plausible IMHO.
Update...I have called big parts houses,the pump is $500.oreillys has got a new plastic tank,pump,New strapes,and 3year warrenty for $349.ill keep tall posted.