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Discussion Starter · #1 ·
ok this truck has inline 6 4.9 manual trans....when you try to start it.. fuel pump stays on does not cycle off after turning key on...if you can get it to start (not very often)in chugs and blows smoke and runs like hell....if you floor it while its doing this it clears up and revs fine but goes back to runnin like crap when u let off pedal...if you can get pump to cut off when u turn key on it seems to start ok....it also has developed a wanting to die sometimes driving it around....problem is very bad when cold..............help very much apprieciated!!!!!
 

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2013 F-150 XLT 4WD with 5L
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When the ignition switch is turned to the ON position, the PCM energizes the fuel pump relay for 2 seconds allowing the fuel pump to pressurize the fuel system. If the PCM does not receive any ignition reference pulses (engine cranking or running) within 2 seconds, the PCM de-energizes the fuel pump relay; this causes the fuel pump to stop.

Any interruption in this operation can cause your problem. The pump itself could be bad as well as the PCM. That said, before you go swapping out anything, check your wiring and make sure you have a good ground to the pump as I have seen that cause this same issue.
 

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Discussion Starter · #3 ·
When the ignition switch is turned to the ON position, the PCM energizes the fuel pump relay for 2 seconds allowing the fuel pump to pressurize the fuel system. If the PCM does not receive any ignition reference pulses (engine cranking or running) within 2 seconds, the PCM de-energizes the fuel pump relay; this causes the fuel pump to stop.

Any interruption in this operation can cause your problem. The pump itself could be bad as well as the PCM. That said, before you go swapping out anything, check your wiring and make sure you have a good ground to the pump as I have seen that cause this same issue.
thanks for your help....dumb question...where is the fuel pump grounded so I can check...thank you once again..
 

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2013 F-150 XLT 4WD with 5L
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1,777 Posts
The ground for the electric fuel pump is likely up near the relays under the hood. Determine the color of the power wire, locate it up by the relays and then the other side should be ground wires. All of them should be solid.
 
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