fuel pressure problem
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New User
Joined: Dec 2010
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fuel pressure problem
Hello this is my first post I am looking for some help, Last week my fuel filter cap cracked and broke during start up, thought it might have been a bad filter because I had just replaced one week before. I replaced the broke one with a new one and a week later it did it again. The truck hasnt sounded normal on start up and fuel milage went to crap about 3 weeks ago. It appears that there is a problem I am just not sure what. Any ideas? Thanks very much!
2002 f-250 7.3 stock truck 250,000 miles
2002 f-250 7.3 stock truck 250,000 miles
Cargo Master
Joined: Jun 2010
Posts: 2,771
Likes: 3
From: Louisiana
How did the fuel look? Like normal fuel or more of a black? Your fuel pressure regulator might be plugged. Man it seemed like it would take quite a bit of pressure to brake the cap, more than the fuel pump would put out! In normal operating conditions max pressure shouldn't exceed 60 psi or so.
Elder User
Joined: Oct 2005
Posts: 786
Likes: 0
From: Reno nv
sounds like crud in the regulator/return line that allowed overpressure. you can break a cap with regular fuel pump if the pressure goes to more than 75 psi, this might explain why it is running cruddy also.
Post Fiend
Joined: Feb 2007
Posts: 14,541
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From: Dallas-Ft. Worth
It should take a lot more than that to break a cap. It takes quite a bit of force to tighten & loosen the thing, more than what the pump would put on it by far. I've had my pressure up to 80+ psi with no issues. Are you sure the lids are going on correctly?
Cargo Master
Joined: Jun 2010
Posts: 2,771
Likes: 3
From: Louisiana
I can see how it would be hard to check pressure if he keeps bustin caps!
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New User
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The filter bowl is clean and fuel is normal color, were is the fuel pressure regulator located?
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Cargo Master
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Cargo Master
Joined: Oct 2009
Posts: 2,500
Likes: 14
From: South Carolina
Here is a picture, compliments of Guzzle's site. Note the arrow near the top, it is pointing towards the return/regulator.
Take that apart to see if it is clogged. Be very careful with the small housing (held in place by two screws). It is brittle.
Take that apart to see if it is clogged. Be very careful with the small housing (held in place by two screws). It is brittle.
)
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
This is a LINK to installing Guzzle's billet FPR Housing. Great info for FPR R&R.
If you're careful there is no need to remove the fuel bowl.
You really need a fuel pressure gauge to check pressure after an FPR R&R. If the spring gets cocked the fuel pressure will
hit about 100 PSI or more. Ask me how I know.
FPR Diagram:
If you're careful there is no need to remove the fuel bowl.
You really need a fuel pressure gauge to check pressure after an FPR R&R. If the spring gets cocked the fuel pressure will
hit about 100 PSI or more. Ask me how I know.
FPR Diagram:
Post Fiend
Joined: Sep 2003
Posts: 6,096
Likes: 26
From: Mesa AZ
The stock fuel pump puts out about 100 psi at idle. The stock fuel filter cap can handle that pretty easily. Aftermarket caps could be a lot weaker though....
If you can borrow a good fuel pressure gauge it would show you if your FPR is sticking. I am having problems with mine right now as well. You can try and clean it but the rubber seal on the poppet gets smashed to oblivion and needs to be replaced. I will have to order this kit to fix it correctly.
Replacement O-rings for Ford Diesel Engines
I was able to get mine working so-so by substituting an o-ring for the seal but it's not really the right way to fix the issue. The kit above is a better way.
Here are some photos that may help.
If you can borrow a good fuel pressure gauge it would show you if your FPR is sticking. I am having problems with mine right now as well. You can try and clean it but the rubber seal on the poppet gets smashed to oblivion and needs to be replaced. I will have to order this kit to fix it correctly.
Replacement O-rings for Ford Diesel Engines
I was able to get mine working so-so by substituting an o-ring for the seal but it's not really the right way to fix the issue. The kit above is a better way.
Here are some photos that may help.
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
If anyone has the change, about 100 bucks, these two things are great upgrade and maintenance items.
Guzzle's Billet FPR Housing and FPR Rebuild Kit.
I did it and it's one less thing to worry about for the next 100k+ miles and my fuel pressure is about 73 PSI KOEO
with black spring installed, and never dips below 65 PSI at WOT. My poppet valve seal was toast.
Nice info and pics Greg. tried to rep you but no go.
Guzzle's Billet FPR Housing and FPR Rebuild Kit.
I did it and it's one less thing to worry about for the next 100k+ miles and my fuel pressure is about 73 PSI KOEO
with black spring installed, and never dips below 65 PSI at WOT. My poppet valve seal was toast.
Nice info and pics Greg. tried to rep you but no go.
Post Fiend
Joined: Sep 2003
Posts: 6,096
Likes: 26
From: Mesa AZ
If anyone has the change, about 100 bucks, these two things are great upgrade and maintenance items.
Guzzle's Billet FPR Housing and FPR Rebuild Kit.
I did it and it's one less thing to worry about for the next 100k+ miles and my fuel pressure is about 73 PSI KOEO
with black spring installed, and never dips below 65 PSI at WOT. My poppet valve seal was toast.
Nice info and pics greg. tried to rep you but no go.
Guzzle's Billet FPR Housing and FPR Rebuild Kit.
I did it and it's one less thing to worry about for the next 100k+ miles and my fuel pressure is about 73 PSI KOEO
with black spring installed, and never dips below 65 PSI at WOT. My poppet valve seal was toast.
Nice info and pics greg. tried to rep you but no go.
With the 'incorrect' o-ring, my pressure is right about 80 psi now and drops to 55 at WOT. I'll still order the rebuild kit anyway because I think my poppet is shot. After looking at your 'old vs new poppet valve' photo, I can see how worn mine is after all.
SPONSOR
Joined: May 2010
Posts: 453
Likes: 18
From: Weldona, CO
Due to the extra thickness of an o-ring rather than using the molded poppet seat, the poppet is close to the maximum travel distance that it can move out when opening. The spring is compressed when in this position and what you have done by using an o-ring is to do a modified regulator shim mod.... LOL
80 psi is more pressure than what you want with stock injectors and a basic rule of thumb is anything over 70 psi will not yield any performance increase and will usually only result in a decrease in fuel mileage.
The 25 psi fuel pressure drop at WOT is a concern and should not be that great with a fuel pump in good condition. It could also be a symptom of having a restriction in the tank that is starving the pump during WOT demand. Your posts show the importance of having a fuel gauge that is readable in cab when determining if you are having fuel pressure issues. An underhood gauge will do nothing for you at all.
80 psi is more pressure than what you want with stock injectors and a basic rule of thumb is anything over 70 psi will not yield any performance increase and will usually only result in a decrease in fuel mileage.
The 25 psi fuel pressure drop at WOT is a concern and should not be that great with a fuel pump in good condition. It could also be a symptom of having a restriction in the tank that is starving the pump during WOT demand. Your posts show the importance of having a fuel gauge that is readable in cab when determining if you are having fuel pressure issues. An underhood gauge will do nothing for you at all.
__________________
Specializing in Viton® o-rings and leak repair kits for the 7.3L and 6.0L diesels
(970) 368-4455 aka guzzleguzzle's Mods & Maintenance website
Specializing in Viton® o-rings and leak repair kits for the 7.3L and 6.0L diesels
(970) 368-4455 aka guzzle
Post Fiend
Joined: Sep 2003
Posts: 6,096
Likes: 26
From: Mesa AZ
Due to the extra thickness of an o-ring rather than using the molded poppet seat, the poppet is close to the maximum travel distance that it can move out when opening. The spring is compressed when in this position and what you have done by using an o-ring is to do a modified regulator shim mod.... LOL
80 psi is more pressure than what you want with stock injectors and a basic rule of thumb is anything over 70 psi will not yield any performance increase and will usually only result in a decrease in fuel mileage.
The 25 psi fuel pressure drop at WOT is a concern and should not be that great with a fuel pump in good condition. It could also be a symptom of having a restriction in the tank that is starving the pump during WOT demand. Your posts show the importance of having a fuel gauge that is readable in cab when determining if you are having fuel pressure issues. An underhood gauge will do nothing for you at all.
80 psi is more pressure than what you want with stock injectors and a basic rule of thumb is anything over 70 psi will not yield any performance increase and will usually only result in a decrease in fuel mileage.
The 25 psi fuel pressure drop at WOT is a concern and should not be that great with a fuel pump in good condition. It could also be a symptom of having a restriction in the tank that is starving the pump during WOT demand. Your posts show the importance of having a fuel gauge that is readable in cab when determining if you are having fuel pressure issues. An underhood gauge will do nothing for you at all.
). You should expect to see an order from me for a rebuild kit. Might order 2 (one for each truck...)