7.3 PSD Fuel Bowl Test Ports
#17
05-02-2013, 09:34 AM
Cargo Master
I have an early 99. Where are these shrader valves located? Ive looked all over the bowl and rail
https://www.ford-trucks.com/forums/2...-location.html
http://www.thedieselstop.com/forums/...-valve-295499/
#19
05-02-2013, 09:03 PM
Mountain Pass
Join Date: May 2013
Location: Garden City, Mi
Posts: 205
Likes: 0
Received 0 Likes
on
0 Posts
#20
05-03-2013, 01:00 AM
quick question about Fuel Bowl
The filter element actually has two parts. The main filter media filters the fuel going to the injectors and makes up the majority of the unit. The umbrella screen filters out any large particles from the fuel that travels to the regulator on it's way back to the tank.
The upper test port is "pre-filter" but "post screen". The lower test port is "post-filter", so on a stock system this is the best place to take fuel pressure readings if you want to see what the injectors are seeing. If you suspect a restriction with the fuel filter element, then you can compare the pressure readings from the upper and lower ports to make a diagnosis. (It is best to measure the fuel pressure under load to highlight any delta between the two ports.)
Neither port will tell you what pressure your fuel pump is putting out because it's regulated at the bowl. If you want to measure fuel pump pressure you will need to connect your gauge to the output of the pump or block the FPR while taking a reading from the upper port. If you decide to block the FPR, then you don't want to do that for too long because the bowl will be exposed to 100 psi +- and it could cause other problems.
There is no way to adjust pump pressure. However there are a few ways to adjust the bowl pressure if you desire. One method is to shim the spring in the FPR which will increase pressure. You can also get an assortment of springs from vendors such as Diesel O Rings or Riffraff Diesel. Depending on which spring you install in the FPR...the pressure will be raised or lowered inside the bowl. Factory specs for bowl pressure is about 55 psi +- (if I remember correctly...).
If your fuel system is modified in any way, then everything I just said is null and void depending on what changes have been made.
Hope this helps.
The upper test port is "pre-filter" but "post screen". The lower test port is "post-filter", so on a stock system this is the best place to take fuel pressure readings if you want to see what the injectors are seeing. If you suspect a restriction with the fuel filter element, then you can compare the pressure readings from the upper and lower ports to make a diagnosis. (It is best to measure the fuel pressure under load to highlight any delta between the two ports.)
Neither port will tell you what pressure your fuel pump is putting out because it's regulated at the bowl. If you want to measure fuel pump pressure you will need to connect your gauge to the output of the pump or block the FPR while taking a reading from the upper port. If you decide to block the FPR, then you don't want to do that for too long because the bowl will be exposed to 100 psi +- and it could cause other problems.
There is no way to adjust pump pressure. However there are a few ways to adjust the bowl pressure if you desire. One method is to shim the spring in the FPR which will increase pressure. You can also get an assortment of springs from vendors such as Diesel O Rings or Riffraff Diesel. Depending on which spring you install in the FPR...the pressure will be raised or lowered inside the bowl. Factory specs for bowl pressure is about 55 psi +- (if I remember correctly...).
If your fuel system is modified in any way, then everything I just said is null and void depending on what changes have been made.
Hope this helps.
#22
05-03-2013, 02:23 PM
The fuel lines are rigid steel tubing that run from the fuel bowl to each cylinder head. The left side is a short run while the right side runs all the way back towards #7 cylinder. The rigid steel lines have Parker sleeves which seal up against the fittings. This allows the lines some flexibility so they don't break when the engine twists.
Here is a diagram.
(I don't remember where I found this...it's possible I stole it from someone else's previous post....)
#23
03-21-2014, 09:09 AM
further bowl questions
I know its an older thread, but am wondering if any of you fuel bowl pros can tell me if the bowl can handle this plan.
I plan on adding a second fuel system (wvo) and using the deadhead approach. I have splitshot injectors on a 2003 e350, which means high pressure spikes that will ultimately cause failure in the small check valves I'd need to install in the head to make the dual fuel deadhead approach work.
Plan B is to install a larger more robust check valve between the diesel tank and the fuel filter/bowl....and to add a fuel selector/solenoid valve on the return line between the bowl and the tank. This valve would be open during diesel function and closed during veg oil function. It would essentially work to prevent backflow of veggie oil into the diesel system.
Is this going to be additional and potentially detrimental pressure to the bowl? Or can it handle it? It seems that if these fuel systems normally have pressure spikes of 150 psi than this plan wouldn't be a problem, but I've been wrong so many times about these things that I thought I'd ask.
Thanks guys
I plan on adding a second fuel system (wvo) and using the deadhead approach. I have splitshot injectors on a 2003 e350, which means high pressure spikes that will ultimately cause failure in the small check valves I'd need to install in the head to make the dual fuel deadhead approach work.
Plan B is to install a larger more robust check valve between the diesel tank and the fuel filter/bowl....and to add a fuel selector/solenoid valve on the return line between the bowl and the tank. This valve would be open during diesel function and closed during veg oil function. It would essentially work to prevent backflow of veggie oil into the diesel system.
Is this going to be additional and potentially detrimental pressure to the bowl? Or can it handle it? It seems that if these fuel systems normally have pressure spikes of 150 psi than this plan wouldn't be a problem, but I've been wrong so many times about these things that I thought I'd ask.
Thanks guys
#24
04-24-2014, 07:40 PM
Pressure
I'm new to diesel and did some reading on a fuel pressure gauge and some one said if your running pretty much stock can use the post filter port witch I did. But no one said what the pressure should be. Does anyone know what it should be? Right now it at 49 at idle. On load it's about 40. All I have done is dp tuner, riff raff plenum boots, riff raff hpx, and some gauges to keep a eye on things. Any help will be great.
#25
04-24-2014, 08:03 PM
I'm new to diesel and did some reading on a fuel pressure gauge and some one said if your running pretty much stock can use the post filter port witch I did. But no one said what the pressure should be. Does anyone know what it should be? Right now it at 49 at idle. On load it's about 40. All I have done is dp tuner, riff raff plenum boots, riff raff hpx, and some gauges to keep a eye on things. Any help will be great.
#26
04-25-2014, 11:26 AM
I'm new to diesel and did some reading on a fuel pressure gauge and some one said if your running pretty much stock can use the post filter port witch I did. But no one said what the pressure should be. Does anyone know what it should be? Right now it at 49 at idle. On load it's about 40. All I have done is dp tuner, riff raff plenum boots, riff raff hpx, and some gauges to keep a eye on things. Any help will be great.
#27
04-25-2014, 04:04 PM
Your reading is a little lower than what Ford recommends but not by much. 50-55 psi is considered to be the normal range for a stock vehicle. In stock tune, you shouldn't drop below 45 psi at WOT so a 20% in fuel pressure at WOT (down to 40 psi) might indicate a possible fuel flow issue. You might consider trying a new fuel filter and/or possibly running some grey bottle Diesel Kleen in your next tank. I have personally seen a truck with 30 psi at idle (my wife's truck)... a bottle of Diesel Kleen restored the pressure back to 55-58 psi range. My best guess is the DK might have helped clean some of the screens inside the mixing chamber in the fuel pickup assembly in the tank. Seems to run fine now...
Ok I'll give diesel Kleen a try. I did just replace the fuel filter. I use the filters from diesel oring. Thankx
Thread
Thread Starter
Forum
Replies
Last Post
Tom Callan
1987 - 1996 F150 & Larger F-Series Trucks
6
03-04-2014 12:00 PM
86lx
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
6
05-02-2005 10:03 PM
