Notices
1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by: DP Tuner

Fuel System

Thread Tools
 
Search this Thread
 
Old Oct 10, 2009 | 10:28 AM
  #1  
74baja's Avatar
74baja
Thread Starter
|
Elder User
Joined: Oct 2007
Posts: 672
Likes: 0
From: NJ
Fuel System

Hi all,
I have been reading up on the common 7.3 fuel system mods (hutch, harpoon, RR etc.) but I think in order to understand them better, I need a better understanding of the stock fuel system. Could anyone describe it, or better yet, provide a diagram?
Thanks
 
Reply
Old Oct 10, 2009 | 11:40 AM
  #2  
Izzy351's Avatar
Izzy351
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
It's actually fairly simple. The pickup in the tank feeds the pump on the fuel rail. The lines between them have quick disconnects that leak under vacuum. The fuel pump feeds the fuel bowl in the valley of the engine. There the FPR and return line makes it's way back to the tank. There are also two feed to each of the head from the passenger side of the bowl, and drain on the rear of it (yellow handle). The pickup also contains screens that can get clogged up, and the return line actually feeds directly into the pickup. And there is a small duckbill aux pickup on the side of it to allow the system to suck fuel if the pick up foot gets clogged. That entire ***'y is removed when the Hutch is done, and the return line is extended away from the pickup. Lastly, the line between the pump & tank is replaced with a piece of hose with a filter of some type put in line there.

Hope that helps...
 
Reply
Old Oct 10, 2009 | 12:03 PM
  #3  
74baja's Avatar
74baja
Thread Starter
|
Elder User
Joined: Oct 2007
Posts: 672
Likes: 0
From: NJ
Thanks Joe, great post (reps). So there is only one fuel pump, the one on the frame rail under the driver's seat?
 
Reply
Old Oct 10, 2009 | 12:05 PM
  #4  
Izzy351's Avatar
Izzy351
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
Correct. And the stock system (mod'ed, of course) is plenty for more HP than the stock block can handle. The Hutch/Harpoon & Reg Return/CCK is all I'd do (and all I have done) to mine.
 
Reply
Old Oct 10, 2009 | 01:02 PM
  #5  
ernesteugene's Avatar
ernesteugene
Postmaster
Joined: Jun 2006
Posts: 2,647
Likes: 0
From: Fulltime RVer
Club FTE Gold Member
Here's a diagram...


 
Reply
Old Oct 10, 2009 | 01:07 PM
  #6  
Izzy351's Avatar
Izzy351
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
That's close, but missing the mixing chamber in the tank. The return line ties directly to it, which makes the aeration issue more problematic. The more air that gets sucked in and sent to the return, the more air is in turn sucked into the pump until eventually, I can imagine it running on foam. Not a very smart design...
 
Reply
Old Oct 10, 2009 | 02:09 PM
  #7  
jkidd_39's Avatar
jkidd_39
Posting Guru
Joined: Dec 2003
Posts: 2,392
Likes: 0
From: NW Arkansas
Originally Posted by Izzy351
That's close, but missing the mixing chamber in the tank. The return line ties directly to it, which makes the aeration issue more problematic. The more air that gets sucked in and sent to the return, the more air is in turn sucked into the pump until eventually, I can imagine it running on foam. Not a very smart design...
I think you have to look at the reasoning of the ford engineers. Which is a bigger issue... Clogging the pick up and the truck is stranded? or The system gets some air in it?

I would say that the obvious best choice is the hutch w/ an pre pump filter. But I understand the logic behind the design.

Now I am not trying to be a d!ck or anything just saying that air in the system is better than dropping a tank on the side of the road.
 
Reply
Old Oct 10, 2009 | 02:31 PM
  #8  
Izzy351's Avatar
Izzy351
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
The screens in the mixing chamber can STILL clog. That's one of the reasons we get rid of it, because if they clog, you'll still have to drop the tank. Air getting in there just adds to asinine design, because they followed that with a dead-head fuel feed from the bowl. And I don't think you're being a d!ck, just for the record. LOL
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-1

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-2

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-3

Every 2026 Ford Engine Explained

 Brett Foote
story-4

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-5

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-6

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-7

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-8

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-9

Top 10 Ford Truck Tragedies

 Joe Kucinski
Old Oct 10, 2009 | 03:22 PM
  #9  
74baja's Avatar
74baja
Thread Starter
|
Elder User
Joined: Oct 2007
Posts: 672
Likes: 0
From: NJ
Cool stuff, guys. So, with this added info, why does #8 deadhead? I've seen CCTs where #8 scores much worse than all the others, and it is normal. What's the deal? I've read about it before, but never fully understood why, or why a cross-over would help. Also, why cross-over the high-pressure oil?
 
Reply
Old Oct 10, 2009 | 03:31 PM
  #10  
Izzy351's Avatar
Izzy351
Post Fiend
Joined: Feb 2007
Posts: 14,541
Likes: 2
From: Dallas-Ft. Worth
Injector #6 fires just before #8, and they're right next to each other. The theory is that #8 is shorted a little fuel, so they put in an AE that shoots in a little more fuel to make up for the difference. When you put in the CCK or RR, the fuel isn't dead-headed there, so you can put in a regular AD injector, if you wish. I was going to do that, but decided not to because I knew I was putting in a complete set of hybrids at some point (which I have since done). The RR or CCK also allows any air making it past the fuel bowl to be sent through the heads to the return line without necessarily going through your injectors. This makes it much easier to purge all the air from the system with a few cycles of the key. I know when I have my system open, I just cycle the key three times before I start the engine. Never had any problems with air in it.

The HPX is completely different. That is for connecting the high-pressure oil rails together, which evens out the pressures on the system allowing for a smoother, quieter engine.
 
Reply
Old Oct 10, 2009 | 03:35 PM
  #11  
74baja's Avatar
74baja
Thread Starter
|
Elder User
Joined: Oct 2007
Posts: 672
Likes: 0
From: NJ
Ahhhh, I see. Thanks all!
 
Reply
Old Oct 10, 2009 | 04:21 PM
  #12  
clux's Avatar
clux
Post Fiend
20 Year Member
Joined: Feb 2002
Posts: 10,600
Likes: 3
From: Carhenge
Originally Posted by jkidd_39
I think you have to look at the reasoning of the ford engineers. Which is a bigger issue... Clogging the pick up and the truck is stranded? or The system gets some air in it?

I would say that the obvious best choice is the hutch w/ an pre pump filter. But I understand the logic behind the design.

Now I am not trying to be a d!ck or anything just saying that air in the system is better than dropping a tank on the side of the road.
The mixing chamber was designed as a cold weather fuel gel prevention system, returning warmed fuel to the mixing chamber to keep warmer fuel flowing through the lines. It works well for that purpose, but returning air is an unfortunate side effect.
 
Reply
Old Oct 15, 2009 | 07:43 PM
  #13  
ernesteugene's Avatar
ernesteugene
Postmaster
Joined: Jun 2006
Posts: 2,647
Likes: 0
From: Fulltime RVer
Club FTE Gold Member
Here's the diagram for a second time and hopefully it'll stay around this time around...

 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ExPACamper
1999 - 2003 7.3L Power Stroke Diesel
11
Jun 16, 2017 12:02 PM
Justus6.0L
6.0L Power Stroke Diesel
4
Feb 15, 2017 03:37 PM
brendo613
1968-Present E-Series Van/Cutaway/Chassis
9
Jun 17, 2016 05:50 AM
lee00
1994.5 - 1997 7.3L Power Stroke Diesel
9
Oct 8, 2015 08:45 AM
ob_one
Exhaust Systems
4
Jun 1, 2012 12:15 AM




All times are GMT -5. The time now is 10:10 PM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE