Why?
Ditto, fill me in!
How to do the bb mod
Thread Starter
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Senior User
Joined: Oct 2009
Posts: 281
Likes: 0
From: West TN
How to do the bb mod
This is how i performed the bb mod on my truck. This mod is to boost fuel pressure up from 55 to about 75. First i removed thermostat housing by removing using a 10 mm. I then pushed the thermostat housing to the front to give me room to remove fuel pressure regulator. Then remove the line on the fpr. The bolts on the fpr are a t27 torx. Remove all four bolts holding it to the upper fuel filter. Watch out because the spring has it under pressure. Make sure the spring and brass poppet valve doesnt fall out. Take a .177 bb and slide it in the brass poppet and reassemble everything. You will lose some coolant doing this mod so make sure you have some on hand. Some companies sell a longer spring but the bb is cheaper.
Lead Driver
Joined: Jun 2007
Posts: 6,757
Likes: 5
From: Corvallis, OR
Its better for the injectors, but it won't raise from 55 to 75. I did the mod because my idle fuel pressure was only 53 and dropped to 44 at WOT, after the BB mod it idles at 62 and drops to just 55psi. 8-10 psi increase is standard.
More Turbo
Joined: Aug 2006
Posts: 598
Likes: 5
From: Burlington, NC
Isn't that harder on the fuel pump? Seems to me it would make the fuel pump work harder and therefore shorten its life. The more I tinker the more I seem to find that not much seems to improve any OEM settings if you are using it as it was intended. Just my thoughts. So, would that not be harder on the fuel pump?
Fleet Owner
Joined: Nov 2003
Posts: 27,881
Likes: 3,595
The pump does not work any harder. The BB is in the regulator that returns fuel to the pump suction. With the BB in the spring, it reduces the fuel return, thus elevating the fuel pressure to the injectors (the pump discharge pressure is not affected much at all).
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Resident smarta$$
Joined: Aug 2006
Posts: 4,929
Likes: 9
From: Oaks,PA
Wow, who thinks of stuff like this? I might have to attempt this, when it gets warmer outside! Bismic, would you say this is a good mod to do?
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Fleet Owner
Joined: Nov 2003
Posts: 27,881
Likes: 3,595
I am either doing this mod or buying an upgraded spring.
I didn't really describe it well in the previous post. The BB isn't acting like a restriction (which is how it sounded after I re-read my previous post), but it is (in effect) making the spring stiffer and thus requiring a higher pressure for the fuel to recycle back.
Cheezit stated that it might be adviseable to get a replacement fuel regulator kit since some internal parts can experience some wear (the plunger). The replacement regulator kit should also come with a stiffer spring. For me, I only have 60k miles, so I do not think I need the replacement regulator kit yet.
I didn't really describe it well in the previous post. The BB isn't acting like a restriction (which is how it sounded after I re-read my previous post), but it is (in effect) making the spring stiffer and thus requiring a higher pressure for the fuel to recycle back.
Cheezit stated that it might be adviseable to get a replacement fuel regulator kit since some internal parts can experience some wear (the plunger). The replacement regulator kit should also come with a stiffer spring. For me, I only have 60k miles, so I do not think I need the replacement regulator kit yet.
Lead Driver
Joined: Jun 2007
Posts: 6,757
Likes: 5
From: Corvallis, OR
Actually, it does make the pump work harder, but I'd rather the pump work harder than the injector feed drop below 45 psi. If you look at pump flow charts, higher pressure creates more current draw for the same flow rate.
Fleet Owner
Joined: Nov 2003
Posts: 27,881
Likes: 3,595
Your fuel pressure is first regulated to 100 psig out of the HFCM, so your pump is really not increasing its pressure based on what is happening at the fuel filter regulator. The fuel pressure is first regulated at the HFCM and then further regulated by this spring loaded regulator at the fuel filter to the 45-65 psig we see with our gauges.
Fleet Owner
Joined: Nov 2003
Posts: 27,881
Likes: 3,595
Here is a pic of the fuel line tie-in where the regulator is:
https://www.ford-trucks.com/forums/p...ictureid=24055
The fuel pressure regulator kit number (if you would want to go that route) is either:
4c4z-9t517-aa
or
3C3Z-9T517-AE
There are two kits one is a reseal kit and one is a complete kit with the housing.
A Tech told me that the one he installs is 3C3Z-9T517-AE it should be the complete kit. It is the same from 03 to 07.
Because of his input, I am not sure what is included in the 4c4z-9t517-aa part.
https://www.ford-trucks.com/forums/p...ictureid=24055
The fuel pressure regulator kit number (if you would want to go that route) is either:
4c4z-9t517-aa
or
3C3Z-9T517-AE
There are two kits one is a reseal kit and one is a complete kit with the housing.
A Tech told me that the one he installs is 3C3Z-9T517-AE it should be the complete kit. It is the same from 03 to 07.
Because of his input, I am not sure what is included in the 4c4z-9t517-aa part.
