Fuel Pressure Question
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From: North of Greenville
Thanks, Tenn.
Since I have the CCK installed, which includes an orifice "bleeder" tee in the cross-connect line, I actually have the option of connecting either there or at the fuel bowl where I installed a tee with a plugged end. In fact, my long term thoughts are to connect the two locations together with a couple of small solenoid switching valves so I can have the in-cab gauge read from either port at the flip of a switch.
I never have removed the stock restrictors, even though I have considered it.
Regarding the gauge, yes, the sender DOES come with the gauge and is included in the price I quoted above.
Since I have the CCK installed, which includes an orifice "bleeder" tee in the cross-connect line, I actually have the option of connecting either there or at the fuel bowl where I installed a tee with a plugged end. In fact, my long term thoughts are to connect the two locations together with a couple of small solenoid switching valves so I can have the in-cab gauge read from either port at the flip of a switch.
I never have removed the stock restrictors, even though I have considered it.
Regarding the gauge, yes, the sender DOES come with the gauge and is included in the price I quoted above.
Fleet Owner
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From: Rio Rico, AZ.
Don't expose that guage to the injector noise that they generate. Put it either in front of the restrictors or put a pressure snubber in the line before the guage.
For an example of what I am talking about, while the engine is idling, lightly touch one of the flex lines on the CCK kit and feel the shock waves that the injectors generate. You DO NOT want to expose your delicate gauge to that sort of thing as it will suffer an early demise or at best the needle will bounce so badly it will be useless.
For an example of what I am talking about, while the engine is idling, lightly touch one of the flex lines on the CCK kit and feel the shock waves that the injectors generate. You DO NOT want to expose your delicate gauge to that sort of thing as it will suffer an early demise or at best the needle will bounce so badly it will be useless.
Post Fiend
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From: Middle Tennessee
Originally Posted by F250_
In fact, my long term thoughts are to connect the two locations together with a couple of small solenoid switching valves so I can have the in-cab gauge read from either port at the flip of a switch.
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From: North of Greenville
Dan, what if I went downstream of the orifice bleeder tee before it ties into the fuel return line that goes from the filter housing back to the tank. IIRC, I think that Jason said that the orifice in that tee is something along the lines of .002-.004", which would take a pretty good pressure drop across the orifice. Only thing I wonder about there is whether or not I would also need to install a check valve so that the discharge pressure from the filter housing could not interfere with the reading.
Another thing is that I've had trouble locating a source for a pressure snubber like you described. Any tips on where to look?
Tenn, I know that a switching valve isn't necessary, but I found a small 3-way, 1/8-inch, 12V Parker valve that is SS and rated for up to 250 psig - it's only about $80 and isn't too large. Installing that would be consistent with my tendency to over-engineer things. The gauge that is already on the bowl is under the hood on a short hose, which means I can't seeit while driving down the road. If I could switch on the run, I could see "street-level" performance issues at either location while driving down the road on test/evaluation runs.
Another thing is that I've had trouble locating a source for a pressure snubber like you described. Any tips on where to look?
Tenn, I know that a switching valve isn't necessary, but I found a small 3-way, 1/8-inch, 12V Parker valve that is SS and rated for up to 250 psig - it's only about $80 and isn't too large. Installing that would be consistent with my tendency to over-engineer things. The gauge that is already on the bowl is under the hood on a short hose, which means I can't seeit while driving down the road. If I could switch on the run, I could see "street-level" performance issues at either location while driving down the road on test/evaluation runs.
Last edited by F250_; Aug 29, 2007 at 10:11 AM.
Post Fiend
Joined: Feb 2006
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From: Middle Tennessee
I know I am not Dan, but orifices are commonly used as a pressure snubber. In this instance, it will not work downstream of your orifice because from there on, there is little pressure as the fuel is simply returning to the tank.
You will want to see what the pressure is before the orifce as that is what you will have at the rail if indeed that is your only return regulating device from the rails. All of this is if I understand your fuel design correctly.
You will want to see what the pressure is before the orifce as that is what you will have at the rail if indeed that is your only return regulating device from the rails. All of this is if I understand your fuel design correctly.
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From: North of Greenville
I understand what you're saying, Tenn, but it is at that point (ahead of the orifice tee) that Dan was saying I needed to stay away from. Kris also has made the same observation by destroying a gauge at that point.
It sounds like I need to tap into the fuel line before it enters the rail. But if I put it there, isn't that the same thing as putting it directly into the tee off the back of the filter housing?
Below is the image of my plumbing setup with the CCK.
It sounds like I need to tap into the fuel line before it enters the rail. But if I put it there, isn't that the same thing as putting it directly into the tee off the back of the filter housing?
Below is the image of my plumbing setup with the CCK.
Post Fiend
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From: Middle Tennessee
[QUOTE=F250_]
Yes, that is my point. Even if you install it off of the bowl, you will see similar pressure except maybe not as much injector noise or gauge bounce. That is why I would use a snubber before the gauge. I believe Kris wrecked a gauge because of no snubber. Ideally, if you could get another orifice T like you have, you could hook the gauge to that and have somewhat of a snubber with the orifice.
It sounds like I need to tap into the fuel line before it enters the rail. But if I put it there, isn't that the same thing as putting it directly into the tee off the back of the filter housing?
Last edited by Tenn01PSD350; Aug 29, 2007 at 12:05 PM.
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Post Fiend
Joined: Feb 2006
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From: Middle Tennessee
Get one from Jason, just like you have. Stand by, I have edited your pic, I will edit it in here in a few once I upload it.
Here you go:
Here you go:
Last edited by Tenn01PSD350; Aug 29, 2007 at 12:10 PM.
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From: North of Greenville
Thanks, Tenn. I have searched before and never been able to find any of these snubbers, but I guess I changed my search phrase a few minutes ago to just the right thing and found them for <$10 from Grainger (local). Only question I have is whether I should get one for a range of 1500 psi, 3000 psi, or 5000 psi.
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From: New York
Pete - Just thought I would chime in on what I would recomend. For fuel pressure I myself use an electric 100psi Autometer oil pressure gage with an electric sending unit. This is able to snub out the shockwaves electrically and give a true (average) reading at the gage without all the pulsations, or having to worry about an isolator, snubber, or fuel in the cab. I have had mine connected directly to the rails for 3 years now with no issues. The easiest way to tie it in would be to remove the T with the orifice in it and drill and tap a 1/8npt hole in the side, then you can connect your sending unit straight to the T, or run a hose to a remote mount location. Once I burn through my current inventory, I will include a T that already has a spare 1/8npt plug. Just some ideas. BTW, your fuel system should read on average between 55-65. Your High pressure oil system will read between 500-3000. Although fuel and high pressure oil are required for the injjectors, they are two completely seperate and isolated systems.
Post Fiend
Joined: Feb 2006
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From: Middle Tennessee
Now I am getting beyond my technical expertise level. I would think any gauge/sender designed to handle up to 100psi would be good except for the noise or pulsations in the fuel rails from the injectors. I don't know if a 1500psi or greater snubber will provide an adequate signal or not.
Perhaps Jason or Dan or someone else will chime in because I do not know. I do know when I use my cheapie gauge on the dead end bleed of mine, it bounces a good 5psi. If I kink the gauge, it settles down to a steady reading meaning a flow restrictor ought to do the trick. What size that is I cannot say. Good luck.
Edit. there you go.
Perhaps Jason or Dan or someone else will chime in because I do not know. I do know when I use my cheapie gauge on the dead end bleed of mine, it bounces a good 5psi. If I kink the gauge, it settles down to a steady reading meaning a flow restrictor ought to do the trick. What size that is I cannot say. Good luck.
Edit. there you go.
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From: North of Greenville
Thanks, Jason and Tenn (and Dan).
Sounds like what I am planning to install, then, will take care of giving me the pressure I want without problems from pulsations. I just wasn't sure if the sender would physically handle the pressure pulsations. I appreciate you guys being so patient with what feels like endless questions in my mind.
Now I can't wait for the gauge to get here and get it installed. If my wild hair takes over, I'll go ahead and put the flip-switch and 3-way solenoid valve in at the same time.
Sounds like what I am planning to install, then, will take care of giving me the pressure I want without problems from pulsations. I just wasn't sure if the sender would physically handle the pressure pulsations. I appreciate you guys being so patient with what feels like endless questions in my mind.
Now I can't wait for the gauge to get here and get it installed. If my wild hair takes over, I'll go ahead and put the flip-switch and 3-way solenoid valve in at the same time.
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After thinking about that 3-way valve and flip switch discussion from yesterday, I've realized that it will be cheaper to use two different sending units and switch between them. Less fuel plumbing (and engine clutter) to go that way too. I think I've almost talked myself into it, now.
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