1986 E350 has no power to fuel pumps


fluedr
05-03-2007, 08:13 PM
We have a 1986 Ford E350 motorhome with a 460 in it. This is the model that has a carb and an electric fuel pump in each of the two tanks. The pumps are fed power when the starting solenoid is engaged but once the starter drops out so do the fuel pumps. I have hot wired the wire feeding the pumps off the solenoid and whenever I turn on the switch to feed the pumps this way they work fine and the engine runs with no problem. Will it harm the system running the pumps this way or where would I look for an electrical problem that supplies power to these pumps while the engine is running and not cranking. Does anyone have a wiring diagram for this model or know where I can buy one. I have tried our local Ford dealer and he says he has nothing on that model and to drive it the way it is wired now.

lankin g
05-23-2007, 01:11 PM
I have a 1984 ford econoline RV with a 351 engine. The unit ran out of gas twice shortley after I stopped to refuel both tanks. I rewired an inline electric fuel pump on the rear tank only , directly to the battery with a clip and limped it home. I can only get the pumps to work if I take the wire off the "I" terminal on the starter solinoid and hook it up directly.when I test the new solinoid there is still no power to the "I" terminal. A fellow said to make sure the solinoid is grounded. On this unit it has a fuel saftey shutoff . it's mounted down by the passengers right leg , it's about 2"x2" . This could be a problem. Also the tank selector valve seems to switch the fuel pumps on and off for each tank when called for but the fuel does'nt seem to be flowing past the valve. I don't know if I have 2 seperate problems or a combination of 1. I'm in the middle of this nightmare and will let you know if I fiqure it out. thanks .

skeezix3
01-04-2008, 02:24 AM
I have a 1984 ford econoline RV with a 351 engine. The unit ran out of gas twice shortley after I stopped to refuel both tanks. I rewired an inline electric fuel pump on the rear tank only , directly to the battery with a clip and limped it home. I can only get the pumps to work if I take the wire off the "I" terminal on the starter solinoid and hook it up directly.when I test the new solinoid there is still no power to the "I" terminal. A fellow said to make sure the solinoid is grounded. On this unit it has a fuel saftey shutoff . it's mounted down by the passengers right leg , it's about 2"x2" . This could be a problem. Also the tank selector valve seems to switch the fuel pumps on and off for each tank when called for but the fuel does'nt seem to be flowing past the valve. I don't know if I have 2 seperate problems or a combination of 1. I'm in the middle of this nightmare and will let you know if I fiqure it out. thanks . have you found the problem? i have a 1989 e150 that is acting the same way !

acmeracingpapaw
09-07-2014, 07:05 PM
I also have an 86 E350 motorhome with the 460 engine with the same problem for 10 years now so I decided it was time to find the problem. I untaped every wire on both the 4 wire and the 5 wire fuel pump relays and traced each wire to its origin. The red wire w/yellow stripe on #2 post on the 4 wire relay runs to the back of the engine and hooks to an oil pressure controlled sending unit. The purpose of this sending unit is to shut the engine down if the oil pressure drops to a dangerous low to prevent engine damage. It also lets the fuel pump run a few seconds when you first turn the ignition on. The blue wire on this sending unit goes to the fuse box to the left of the brake pedal. It is the second fuse from the bottom on the right. It says "Module". If this fuse is blown it will cause the same problem. If the fuse is ok then either the sending unit is bad or like mine, it has a bad connection. It will only run the fuel pump a few seconds the first time you turn the ignition on. It will not run the fuel pump again until the engine is started and shut off again. Then when you turn the ignition on the fuel pump will run again. I hope this is beneficial. This should make everything work normal again.

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