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first off i want to thank the group - about 10 years ago you gave info and advice which helped me to make most excelent repairs - no trouble since. but now same truck 1981 ford standard cab dually 400 engine auto. i have been told that the fuel tanks - front left - are suppose to have electric pumps - something i have never had to deal with before - and when i dropped the tank i found only the float assy. the parts catalog shows electric pump on the assy. i have been driving it like this for 20 years just thinking its a dog. i guess it is possible for the mech. pump to pull fuel out of the tank.please tell me this is not right and that someone was messing up the truck before i got it. can someone tell me the right way this should be setup ?
first off i want to thank the group - about 10 years ago you gave info and advice which helped me to make most excelent repairs - no trouble since. but now same truck 1981 ford standard cab dually 400 engine auto. i have been told that the fuel tanks - front left - are suppose to have electric pumps - something i have never had to deal with before - and when i dropped the tank i found only the float assy. the parts catalog shows electric pump on the assy. i have been driving it like this for 20 years just thinking its a dog. i guess it is possible for the mech. pump to pull fuel out of the tank.please tell me this is not right and that someone was messing up the truck before i got it. can someone tell me the right way this should be setup ?
I assume this is an F350 ad IIRC not all of them had ELEC pumps. Do you have a shot of the top of the tank.
The diagram below is the only one in the electrical manual for the 1981 series trucks with dual tanks. Ford makes mistakes all the time in the their manuals and literature, but the diagram below shows no electric fuel pumps, and you do not have electric fuel pumps. If you only have two wires going to your sending units, then it's a safe bet your truck never had electric fuel pumps, you would need another wire to each sending unit to power them.
The diagram below is the only one in the electrical manual for the 1981 series trucks with dual tanks. Ford makes mistakes all the time in the their manuals and literature, but the diagram below shows no electric fuel pumps, and you do not have electric fuel pumps. If you only have two wires going to your sending units, then it's a safe bet your truck never had electric fuel pumps, you would need another wire to each sending unit to power them.
Electric in-tank fuel pumps WERE fitted to some 400 applications. The tanks were unique to that application hence why I asked to see the top of the tank. Cause I cannot recall if all F350 applications had them or not.
The only trucks I'm aware of with electric pumps in 1981 would have been California models with EEC-III ignition systems. My 1981 F350 400 dual tanks has mechanical everything.
Electric in-tank fuel pumps WERE fitted to some 400 applications. The tanks were unique to that application hence why I asked to see the top of the tank. Cause I cannot recall if all F350 applications had them or not.
this truck does have a smog pump but is cat excempt and does have mech pump on the block. but ive been told over and over that it is suppose to have pumps in the tanks and it would explain why the truck is such a dog
The only trucks I'm aware of with electric pumps in 1981 would have been California models with EEC-III ignition systems. My 1981 F350 400 dual tanks has mechanical everything.
YMMV
The F350 with the 400 starting in 80 could have elec pumps, IIRC it was the same in-tank Elec pump Ford used till the late 80's so they should be still available after market.
(A quick check of Rockauto reveals they still are.) https://www.rockauto.com/en/catalog/...fuel+pump,6256
The elec pump was very common on the C&C's and a pile of F350's pick up's had them. And IIRC EEC III was never fitted to the 400 in the F350. The F350's exceeded the maximum GVWR for more stringent emissions so there would be no need to fit EEC III.
The F350 with the 400 starting in 80 could have elec pumps, IIRC it was the same in-tank Elec pump Ford used till the late 80's so they should be still available after market.
(A quick check of Rockauto reveals they still are.) https://www.rockauto.com/en/catalog/...fuel+pump,6256
The elec pump was very common on the C&C's and a pile of F350's pick up's had them. And IIRC EEC III was never fitted to the 400 in the F350. The F350's exceeded the maximum GVWR for more stringent emissions so there would be no need to fit EEC III.
If they did have electric in tank pumps, it would be some oddball early setup or it would have had a oddball fuel tank. When they went to in tank pumps on the 460's, they changed all the tanks to the large sending unit hole style so the pump style sending unit would fit into the tank.
I believe you, but it would not have been something very commonly produced. I suppose if you order enough trucks, Ford would build you anything you wanted.
this truck does have a smog pump but is cat excempt and does have mech pump on the block. but ive been told over and over that it is suppose to have pumps in the tanks and it would explain why the truck is such a dog
Not sure what you mean about the truck being a dog. The 400 is not a powerhouse stock, but it's a workhorse, made to pull heavy loads with no complaints. If everything is working correctly with the engine, it should feel pretty slow empty, and it should feel the same pulling a load. Get what I am saying? It has low end torque, a 302 would probably out run it empty, but put a load of wood in the bed or a trailer behind it, and that will kill the 302, but the 400 is going chug along pretty much like it did empty.
what i mean by a dog is that it does not accelerate very fast at all. but you are right about being a power house, my brother in law broke down and i went to help him. i pulled a mid 90 ford truck extened cab with his trailer load with another full size truck all the way home and almost didnt fell it. 411 or 410 gears it been a while since i have been looking at the rear end. you are so right about being strong. but it is definly not fast.
the harness only has two connections which could tell you no electric pumps. the electric pump in the catalog shows three connections.i cant see how to make that work.
the harness only has two connections which could tell you no electric pumps. the electric pump in the catalog shows three connections.i cant see how to make that work.
No reason to try and make it work. As long as you have a good supply of fuel, the truck will run as good as it's going to with a mechanical pump.
The only reason Ford came out with that in tank pump setup on the 460's (they do list some 351w applications also but I have never seen one) is to combat fuel overheating or "vapor lock" or something related to the fuel getting too hot causing problems. They pumped the fuel from the tank to the top of the engine, where they have a tee fitting up there with a orifice. A portion of the fuel went back to the tank through a return line, and the rest went to the carb bowl. This constant circulation kept the fuel cooler and helped get rid of any vapors forming in the fuel line.
Like your truck, the 460's were workhorses. For large rv's, delivery vans and trucks, sitting there idling on a hot summer day in the middle of city traffic or creeping up a long mountain pass fully loaded. They got to see the worst fuel conditions I suspect.
i am thinking that i should get all this electric pump thoughts out of my head. even if i bought an elec. pump i could not use it because of my harness.i will just get a new pick up assy. with gas level sender and filter. the only complain i ever had with the truck is acceleration. the fuel usage is even acceptable. it will move anything you want. it is solid as a rock, no squeaks, no rattles, a real survivor. never been hit or even dented. never seen one in salvage yard, i live in a city of a million plus and in 22 years only ever seen two of them and that was only one time each, and this is truck country, i would expect more. we actually pulled over the side of the road to check out each others truck.
