Testing fuel pressure
Post Fiend
Joined: Sep 2006
Posts: 7,426
Likes: 6
From: Sioux Falls, SD
They eventually leak and stop working. Sometimes they kind of melt/deform. Always covered by warranty but a hassle. I have a plug in the glovebox. The thing is, my sender is in a port in the head, because I have deleted the fuel bowl. So its a more inconvenient to remove.
The same setup in the Excursion just failed after about 15 months. Electrical in-cab gauge reads 80-85 psi while the mechanical under the hood gauge reads 65.
In both vehicles the sending units are in the fuel bowl.
Kirkharrod - any idea how long the warranty is good for?
Hotshot
Joined: Nov 2006
Posts: 11,286
Likes: 263
From: North of Greenville
I'm not a fan of tubing up fuel lines all over the place, but for those of you who are experiencing multiple failures, would it be worth considering running either a small diameter hard tube or SS flex line over to an open location on the fender wall under the hood, and re-mount the sender there with a shutoff valve for easy access and isolation in the event of any future leaks/failures?
Just a thought.
I do know from experience that an under the hood gauge gives you no troubleshooting opportunity except at idle conditions with the hood open (unless you want to also mount a lighted monitoring camera under the hood as well so you can see the camera display in the cab, but that seems like overkill to me).
Just a thought.
I do know from experience that an under the hood gauge gives you no troubleshooting opportunity except at idle conditions with the hood open (unless you want to also mount a lighted monitoring camera under the hood as well so you can see the camera display in the cab, but that seems like overkill to me).
Fleet Mechanic
Joined: Dec 2010
Posts: 1,546
Likes: 9
From: Wellington, Co
Sorry I am just now catching this. I have had GS for 3 years. Sensor started acting up late last year, got a new one, and mounted remotely with a GS kit. Nice steel braided line. Works great, should work with any under hood sensor. Supposed to dampen vibration which kills sensors mounted on the engine. My sensor gets pressure from the pre filter side of the bowl.
Which is why I was searching. Just installed FRX, with gold spring, supposed to be 62-65 psi. Getting consistent 70-75. How much psi difference is there/should there be between pre filter side and post filter side of bowl?
Thanks.
Tom.
Which is why I was searching. Just installed FRX, with gold spring, supposed to be 62-65 psi. Getting consistent 70-75. How much psi difference is there/should there be between pre filter side and post filter side of bowl?
Thanks.
Tom.
Elder User
Joined: Aug 2013
Posts: 588
Likes: 13
So, the pressure would be less as the filter material becomes contaminated with debris.
The only real way to know is to use a mechanical gauge and check both the supply side and the return side without disturbing the filter.
The actual pressure used by the Injectors via the rail is more like 35 psig at the injector. This number increases with a clean filter and decreases as it becomes contaminated.
While the "Gold Spring" should maintain a given pressure, several things affect the actual pressure. I would think you would receive the same answer from the manufacturer.
70-75 is right at the top limit for the OEM System. So long as the residual measurement does not fall below 42 psig. I would just drive it.
Post Fiend
Joined: Sep 2006
Posts: 7,426
Likes: 6
From: Sioux Falls, SD
On my Excursion the the mechanical fuel pressure gauge on the regulated return shows 63 psi, and the in cab electrical fuel pressure gauge installed on the top passenger side port of the fuel bowl shows 66-67 psi. So I have a 3-4 psi difference between pre & post filter on this setup.
Post Fiend
Joined: Sep 2006
Posts: 7,426
Likes: 6
From: Sioux Falls, SD
when my fuel filter was getting clogged I watched the in cab fuel pressure gauge climb to 70-75 psi. I never had this situation happen before so I assumed it was my electrical gauge sending unit malfunctioning. ISSPRO sent me another sending unit but it read the same - I was wrong, it was my fuel filter getting dirty. Put in a new fuel filter and I was good to go! I must have got some crappy fuel along the way somewhere -..................
Posting Guru
Joined: Jan 2013
Posts: 2,215
Likes: 2
From: North Lake Tahoe
My Isspro sending unit was on its way out just before I pulled the motor, installed it in 2012. I called Isspro and talked with Mike (good dude, just busy and hard to get a hold of sometimes) He replaced my sensor and also gave me a snubber to help with vibration issues. Will see how well it works soon I hope. I do like the idea of moving the sensor to the fender with a braided line though. Might be something I need to do.
Fleet Mechanic
Joined: Dec 2010
Posts: 1,546
Likes: 9
From: Wellington, Co
Thanks all. Just got a reply back from Bob (Orings guy), should not have over 70. Check with a mechanical, maybe try stock spring. I did put a new filter in it at the time.
Might be a week or so before I feel like diving in again.
Will post results.
Might be a week or so before I feel like diving in again.
Will post results.
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Fleet Mechanic
Joined: Dec 2010
Posts: 1,546
Likes: 9
From: Wellington, Co
Dug out my Snap On mechanical gauge, hooked up to the line where my sending unit gets pressure, 65 at idle. I am calling electrical off by about 10%. As long as things stay consistent I am okay with it.
Thanks for the replies. I always learn something.
Tom.
Thanks for the replies. I always learn something.
Tom.
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