Fuel pressure gauge install(with no Schraeder)?

fishEH

Well-known member
Jan 26, 2009
6,927
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Lake Villa, IL
Best way to install a fuel pressure gauge on my '94 D1 with no schraeder valve?
I know I can cut the flexible line and install a Tee, but I thought it'd be cleaner to thread a Tee right into the stock fitting?
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
Unfortunately both of those options require use of the schraeder valve which my truck does not have.
Anybody know the size or thread/pitch of the compression nut in my above picture?

I would think something like the below would be the way to go. Theoretically, you should be able to screw it in between the fuel line and fuel rail.


https://www.summitracing.com/parts/cei-102071

This doesn't answer the question but it's an option that you could work into the mix.


https://discoweb.org/showthread.php?t=61690


As the owner of a RRC sans fuel rail valve I would also be curious to know of a modification to install a port to test for fuel pressure.
 

fishEH

Well-known member
Jan 26, 2009
6,927
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Lake Villa, IL
Can you just swap in a fuel rail with a Schrader valve?

Yeah. But if I'm going to go through that effort I may as well just replace the engine. :D
I have a loose fuel rail. Maybe I'll take it to the hardware store and see if I can match the thread.
 

robertf

Well-known member
Jan 22, 2006
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I know the 3.9 and 4.0 disco is interchangeable. I may have done the swap to get the schrader valve on my 95. It has one now

Should take less than an hour to change
 

fishEH

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Jan 26, 2009
6,927
201
Lake Villa, IL
There's a bit of a difference in the level of effort, unless I am missing something badly. Especially on a 14CUX truck.
I know, I'm just exaggerating. I have a 4.6 14CUX in my garage that my plan is to rebuildand drop in this truck, so my level of dedication to fixing the current engine is not high.

I know the 3.9 and 4.0 disco is interchangeable. I may have done the swap to get the schrader valve on my 95. It has one now

Should take less than an hour to change
I've got a 3.9 and 4.6, both 14CUX, in my garage. I was hoping for a thread on solution. :/
 

WaltNYC

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Mar 3, 2010
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NYC
I think Agent's post makes sense. In this case you are ADDING a schrader between the fuel line and the rail.

It looks like the top of the T goes between the fuel line and the fuel rail while the bottom of the T is a schrader. Maybe I'm reading it incorrectly though.
 

fishEH

Well-known member
Jan 26, 2009
6,927
201
Lake Villa, IL
I think Agent's post makes sense. In this case you are ADDING a schrader between the fuel line and the rail.

It looks like the top of the T goes between the fuel line and the fuel rail while the bottom of the T is a schrader. Maybe I'm reading it incorrectly though.

That's not how I read it....
"Description: Caspers Electronics fuel line tap Schrader tee fittings attach to the fuel rail and allow the addition of a fuel pressure gauge, while also allowing access to the fuel port. They are designed to depress the valve in the fuel rail, eliminating the need to remove the valve for fuel pressure measurement."
 

mearstrae

Well-known member
Mar 15, 2017
143
18
Pennsylvania
I have seen "Saddle Taps" used by air conditioning techs with various size Schrader valves, to allow for use of a gauge, or charging of a system. Maybe a HVAC supplier would have something that would work on a fuel rail. If there's one available, you could install it where ever the best access is. These things just clamp around the pipe and presto you have a Schrader.



'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S
 

Agent

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Jun 20, 2007
669
3
WV
I think Agent's post makes sense. In this case you are ADDING a schrader between the fuel line and the rail.

It looks like the top of the T goes between the fuel line and the fuel rail while the bottom of the T is a schrader. Maybe I'm reading it incorrectly though.

That was my though too, but the discription doesn't seem to match with what it looks like in the picture.
 

WaltNYC

Well-known member
Mar 3, 2010
707
135
NYC
Yeah, it appears to be different. It looks like a solid idea if the right type of T can be found.