fuel pump wont prime
fuel pump wont prime
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
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Let me see if I understand this correctly; the fuel pump runs, but won't pump? So the truck won't run? When you first turn on the key the pump should run for about a second then shut off, so it just keeps running at this point?
If the pump is running, and especially if you just replaced it, it should be pumping. If it's not, there must be a blockage somewhere, perhaps in the pickup screen, the line coming out of the tank, or the filter. Have you disconnected the line from the filter and put it into a plastic bottle to see if anything comes out when you run the pump?
Has anyone worked on it and left a jumper wire on the EEC test connector plug that would make the FP keep running like that? Look at the EEC test connector and make sure there's no jumper wire in the end of it, it should be bare.
The fuel pump relay might be worth checking as well.
https://www.ford-trucks.com/guidelines.html
Let me see if I understand this correctly; the fuel pump runs, but won't pump? So the truck won't run? When you first turn on the key the pump should run for about a second then shut off, so it just keeps running at this point?
If the pump is running, and especially if you just replaced it, it should be pumping. If it's not, there must be a blockage somewhere, perhaps in the pickup screen, the line coming out of the tank, or the filter. Have you disconnected the line from the filter and put it into a plastic bottle to see if anything comes out when you run the pump?
Has anyone worked on it and left a jumper wire on the EEC test connector plug that would make the FP keep running like that? Look at the EEC test connector and make sure there's no jumper wire in the end of it, it should be bare.
The fuel pump relay might be worth checking as well.
More Turbo
Joined: Jun 2004
Posts: 690
Likes: 0
From: Sweden
With the caveat that I only know about the '87 E150 302:
The fuel pumps run continuously when the engine runs. The fuel pressure regulator bleeds off the pressure by bleeding the fuel back into the tank through the return line. Unlike some other systems, there is no feedback that shuts off the pump when the output pressure meets the desired pressure.
Does your engine run??!
The fuel pumps run continuously when the engine runs. The fuel pressure regulator bleeds off the pressure by bleeding the fuel back into the tank through the return line. Unlike some other systems, there is no feedback that shuts off the pump when the output pressure meets the desired pressure.
Does your engine run??!
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New User
Joined: Oct 2005
Posts: 1
Likes: 0
the pump does pump fuel but it takes about 5 min to prime and it will not run properly it wont idle. you have to give it a little gas to keep it going. if you give it too much fuel it dies. also if the pump does prime and you turn the key to off for a second it takes another 5 min to prime
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
Okay, the next thing I'd be checking is the Fuel Pressure, with an eye towards the Fuel Pressure Regulator. It works exactly as Dannym described it in the above post.
It sounds like it's just allowing the fuel to circulate through the system but not build any pressure, like it's wide open to dump it back into the tank. You'll need to check the pressure at the Schrader valve on the fuel rail, it should be around 40 PSI when the pump is running.
It sounds like it's just allowing the fuel to circulate through the system but not build any pressure, like it's wide open to dump it back into the tank. You'll need to check the pressure at the Schrader valve on the fuel rail, it should be around 40 PSI when the pump is running.
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