Fuel supply issues
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Trailering
Joined: Sep 2022
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Likes: 14
Fuel supply issues
I'm having a problem with fuel supply on my OBS 95 f350 7.3. Truck quit on me the other day. I've determined it to be a fuel supply issue. Im trying to figure out if it's my tank switch, fuel pressure regulator, or fuel pump.
My question is will the truck run when I manually fill the fuel bowl even if the tank selector is clogged. In my head it should, and since it is not either the FPR is stuck or the newish pump is bad. Mind you I also get zero psi while cranking at the FPR shrader but the gauge does get fuel going to it(clear hose) making me think at least the low pressure side of the pump works.
Thanks on advance.
My question is will the truck run when I manually fill the fuel bowl even if the tank selector is clogged. In my head it should, and since it is not either the FPR is stuck or the newish pump is bad. Mind you I also get zero psi while cranking at the FPR shrader but the gauge does get fuel going to it(clear hose) making me think at least the low pressure side of the pump works.
Thanks on advance.
Lead Driver
Joined: Apr 2016
Posts: 7,213
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From: Bahstun
suction foot can break off and you need 1/4 tank so get fuel and pieces of foot can get into selector valve.
it will idle on 0 PSI and make some rpms if bowl has fuel in it
the injectors can suck fuel from the tank, that why a vac sensor is on the bowl
clean the screens when changing fuel filter
https://www.ford-trucks.com/forums/1...-to-clean.html
it will idle on 0 PSI and make some rpms if bowl has fuel in it
the injectors can suck fuel from the tank, that why a vac sensor is on the bowl
clean the screens when changing fuel filter
https://www.ford-trucks.com/forums/1...-to-clean.html
Thread Starter
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Trailering
Joined: Sep 2022
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Here's where I'm at. Unhooked the fuel line from the tank selector and put them in a fuel jug, truck still made no fuel pressure and the fuel going through the line was very aerated. Ran it for about 5 minutes like that and still won't accelerate at all. The fuel gauge needle would bounce to 1psi when reved up.
Took off the fuel filter cap and watched the bowl fill as the truck runs so low pressure side of pump works.
Removed the regulator, cleaned the screen and inspected the spring and spool valve, all looked good. When running, the disconnected return line doesn't produce much fuel at all so I don't suspect the FPR to be stuck.
Basically I think I'm down to the newish fuel pump is bad, does that sound right to everyone or am I missing something.
Took off the fuel filter cap and watched the bowl fill as the truck runs so low pressure side of pump works.
Removed the regulator, cleaned the screen and inspected the spring and spool valve, all looked good. When running, the disconnected return line doesn't produce much fuel at all so I don't suspect the FPR to be stuck.
Basically I think I'm down to the newish fuel pump is bad, does that sound right to everyone or am I missing something.
Lead Driver
Joined: Apr 2016
Posts: 7,213
Likes: 1,342
From: Bahstun
If fuel going through the line was very aerated, that needs to be addressed.
Bowl system can remove some air but injectors likes to have no air at all.
Two stage pump, it needs the bowl full to make high pressure
You can test the high pressure side to rule out the pump
Bowl system can remove some air but injectors likes to have no air at all.
Two stage pump, it needs the bowl full to make high pressure
You can test the high pressure side to rule out the pump
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