1999 F250 V10 Fuel pump stuff..
#1
10-03-2007, 07:38 PM
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1999 F250 V10 Fuel pump stuff..
Anyone have a good write up on how my fuel pump works?
when you turn off the key, are the fuel lines supposed to stay pressurized, to a point where after a day or so they should stll have the same amount of pressure? When you turn the key on and the pump primes, is it on a timer?,or does it shut off at a certain pressure?
how do you tell when a pump is on its way out?, so you can replace it before it dies and leaves you stranded out in the middle of no where?
when you turn off the key, are the fuel lines supposed to stay pressurized, to a point where after a day or so they should stll have the same amount of pressure? When you turn the key on and the pump primes, is it on a timer?,or does it shut off at a certain pressure?
how do you tell when a pump is on its way out?, so you can replace it before it dies and leaves you stranded out in the middle of no where?
#2
10-04-2007, 07:42 AM
You have a "loop type" fuel system with an "in tank" pump, in line fuel filter, and a common fuel rail that is vacuum actuated regulated, and a fuel pressure sensor. The pump is turned on and off by the pressure sensor. Excess fuel is returned to the tank.
On the upper left as facing the motor you should see a Schroeder valve (looks like a tire valve and is sometimes covered with a red or yellow cap)
This is a "air purge" and pressure test port. I do not know the exact specs for the 99 V10 but you should have 30~40 PSI at this port most of the time. The best test is under load at cruise RPM and speed.
The system will keep some pressure when shut off but over time will bleed down to zero. On Key "On" The fuel pump will cycle on until pressure is correct ...in fact the PCM will not fire the plugs until it senses enough pressure to assure a cold start
The system craps out three ways:
The fuel filter is small relative to all the fuel pumped through it and back to the tank so they don't last as long as we like
The fuel pump has a pickup point low in the tank with a screened inlet that can clog with dirt and mud from a bad tank full of fuel
The early fuel pumps (1997~2001) get weak with time and wear out in 5 to 7 years or around 100~120K miles
On the upper left as facing the motor you should see a Schroeder valve (looks like a tire valve and is sometimes covered with a red or yellow cap)
This is a "air purge" and pressure test port. I do not know the exact specs for the 99 V10 but you should have 30~40 PSI at this port most of the time. The best test is under load at cruise RPM and speed.
The system will keep some pressure when shut off but over time will bleed down to zero. On Key "On" The fuel pump will cycle on until pressure is correct ...in fact the PCM will not fire the plugs until it senses enough pressure to assure a cold start
The system craps out three ways:
The fuel filter is small relative to all the fuel pumped through it and back to the tank so they don't last as long as we like
The fuel pump has a pickup point low in the tank with a screened inlet that can clog with dirt and mud from a bad tank full of fuel
The early fuel pumps (1997~2001) get weak with time and wear out in 5 to 7 years or around 100~120K miles
#3
10-20-2015, 09:44 AM
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Fuel Pump Location and Acvess 1999SD Crew 8'Bed
Help! Please. I have 1999 F250SD 4X2 Crew Cab, (Lariat 172" 8'bed) 6.8 EFI V10 Electronic 4Spd. auto trans. My question is please. Can I access the fuel pump by removing the bed, or is the location under the passangers seat and not accessible by just removing the bed? Thanks Truck sat for 5 years (divorce -long story) and am now able to see if I can get it running again. thanks gill nielsen
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