Fuel pump
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Fuel pump
I bought a new motor for my 78 f150 and rebuilt the transmission myself, and everything works fine but I can’t get the fuel pump to work. Keep in mind it worked on the previous engine and has probably like 10 hours on the pump itself in total. I have it sitting right inside the engine so when the engine rotates it pushes it down. But I get no suction. What do I do. Anything will help.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
I bought a new motor for my 78 f150 and rebuilt the transmission myself, and everything works fine but I can’t get the fuel pump to work. Keep in mind it worked on the previous engine and has probably like 10 hours on the pump itself in total. I have it sitting right inside the engine so when the engine rotates it pushes it down. But I get no suction. What do I do. Anything will help.
Lead Driver
Joined: Jul 2017
Posts: 9,545
Likes: 1,156
From: San Jose, CA
How long did the pump sit while the engine was being rebuilt? If just a month or two, I don't see that as a problem. But if like some of us that project had the pump sitting for a year or more, your "new" pump might just be dead from sitting.
They can sit on the shelf dry and new for quite some time, but once they're used and have some modern gas run through them, they can die in as little as six months. Seen it many times over the past few years unfortunately. Had a new 302 pump go bad in three months while waiting for the wiring to get finished! But at least that was an exception and not the rule so far.
Other than that, can you remove the lines and put your finger over the ports to see if you feel any decent suction? Or have you done that already?
If you do that, try blocking off the output temporarily while you test the input. Sometimes that encourages the pump to prime.
Another way to prime it, if you have not done so already, is to fill the carburetor float bowl with gas through the vent so that at least the engine will start. This higher rpm will often force the pump to prime where just cranking with the starter is not quite enough.
Good luck!
Paul
They can sit on the shelf dry and new for quite some time, but once they're used and have some modern gas run through them, they can die in as little as six months. Seen it many times over the past few years unfortunately. Had a new 302 pump go bad in three months while waiting for the wiring to get finished! But at least that was an exception and not the rule so far.
Other than that, can you remove the lines and put your finger over the ports to see if you feel any decent suction? Or have you done that already?
If you do that, try blocking off the output temporarily while you test the input. Sometimes that encourages the pump to prime.
Another way to prime it, if you have not done so already, is to fill the carburetor float bowl with gas through the vent so that at least the engine will start. This higher rpm will often force the pump to prime where just cranking with the starter is not quite enough.
Good luck!
Paul
Laughing Gas
Joined: Nov 2013
Posts: 1,207
Likes: 60
From: S.E. Louisiana;so far USA
As Paul said, if the diaphragm in the pump get wet with fuel it's best to keep it wet continuously. If it dries out the diaphragm can become very stiff and brittle. Then when it gets moved it will crack & leak. You probably just need another pump.
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executive284
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Feb 23, 2006 06:56 PM
