schraeder adapter for fuel pressure

dgr

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Anyone know where to get an adapter for there to barb or pipe thread? I was about to cut up my bicycle pump last night whentheneighbor handed me a core tool so I could check my pressure
 

icanfixall

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I think that the fitting threads in the aluminum housing is 1/8x27 national pipe threads. BTW that takes a drill size "R" to drill it out so you can cut those threads in the hole... Just some added info for others reading this... We can never get too much onformation...
 

gandalf

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Its a bit hard to tell exactly what you're asking, but I'll take a stab at an answer. I think you're asking about checking the fuel pressure. I'll address that.

I have my fuel filter header set up to read fuel pressure coming out of the filter, going to the IP. I have a cheap pressure gauge permanently installed, as you can see in the attached picture. I also have the schraeder valve unmolested, in case I need to bleed the filter head.

Based on the picture, what are you trying to do?


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dgr

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Ken,
The Schraeder valve will give me an accurate pressure reading,right? I am looking for an item that I can screw onto it and put a piece of hose in the other end and connect that to a pressure gauge. I have no need our desire to either disassemble it our permanently mount a gauge. Every fuel pressure test kit i have seen has adapters to screw onto various test Ports. I am looking for just the one for our style valve. I don't need a whole kit
 

icanfixall

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The picture Ken posted is a great pic of the filter housing ports. I can tll you what they are to. The first port with the tire cap on it is the schrader valve. ?Almost the same thing as any tire valve. Its location is on the inlet side of the filter to purge out the air thats entering the filter. The nest port with the clear hose on it is the air purge on top of the filter. It is open only when there is air trapped in the filter. When that brass fitting sees diesel the small spring in it pushes closed the port. Nice when it actually workes. Now the last port where Ken has the gauge and vacuum fitting. Thats the outlet to the injection punp. Thats where you want a pressure reading. Actually you want a pressure fitting on the inlet and the outlet side of any filter. That way you will see the drop in pressure when the filter gets dirty. The outlet will be much lower than the inlet side.. That sender on the outlet side is actuall a vacuum sender. When the filter gets dirty and the injection pump draws more fuel than the filter can pass it turns into a vacuum on the injection pump side of the filter. Then the dash filter lite turns on... hopefully. I have seen mine turn on only once in over 300,0oo miles and thats the filter that came with the truck when I bought it. The truck had 34,000 miles on it... Yeah, sure... Filters get dirty in that amount of time.... I guess it could happen but I still wonder about it...
 

dgr

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That is a great picture. It is also for a 7.3. My 6.9 doesn't have all those connections.
 

gandalf

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That is a great picture. It is also for a 7.3. My 6.9 doesn't have all those connections.


Okay, the 6.9 filter head doesn't have all three ports. It does not have the last one, the one I have used for the gauge. In that case, I would place the gauge on the port where the schraeder valve is, and always remember that I am measuring pressure from the lift pump, but not pressure coming out of the filter, not necessarily the pressure going into the IP.

The first time I put the pressure gauge on I had it on the schraeder valve port. It worked well there. Then I realized I was measuring pre-filter pressure rather than post-filter pressure. With a clean filter the two should be virtually the same, but with a clogged filter the post-filter pressure will be lower. That's what I wanted to guard against, that lower pressure coming out of the filter. As long as I know pretty closely what the pressure should be and can see what the pressure actually is coming out of the filter, I have a pretty good idea about the condition of the filter.
 

dgr

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Ken,
That's exactly what I an wanting to do. Measure the lift pump pressure as part of a diagnostic routine. Your picture does helpmegreatly. You have a tire cap on there. I should be able to find something for an air shock that will thread on and have a barb on the other end to hook to my hand held pressure gauge. I'm just not having much luck with my google fu in this search
 

Bashby

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Just remove the valve core, slip a hose over it and a hose clamp.
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riotwarrior

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ANY common FI test gauge available at parts stores for 35-50 bucks will have the proper connection you are seeking. Gassers use a schrader valve to on fuel rails. The nice thing about a proper kit, they usually have a bleed off line that drains the fuel off instead of leaving it under pressure when you disconnect it thus spraying fuel all over the place.

I'd suggest you pick up the correct tool and add it to you collection...who knows when you'll need to diagnose an issue with a gasser that has the same port, but if/when you do...well you can deal with it.

An inexpensive kit like this can save you or friends or family a lot of headache and costs associated with diagnosing a fuel problem

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Or for those who are tool ******...:rolleyes: NOT ME:sly:backoff...Something like this may find it's way home....

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But for the average Joe/Josephine...that first one's all a guy needs...
 
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cbarm

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If I was gonna mount a permenant dash gauge for this then can I juat plug it into the tire valve?
 

riotwarrior

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If I was gonna mount a permenant dash gauge for this then can I juat plug it into the tire valve?
If electric that's a safe method if mechanical you will need an isolator to isolate the fuel from the gauge so no fuel comes INTO the cabin of the vehicle.

I guess you could install it on the schrader, however, this would subsequently remove the option of bleeding air from that location. Better to T in as gandalf has shown.

Isolater with MECHANICAL gauge shown here

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icanfixall

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Great idea with the pressure gauges posted above. The part about using an isolater so no fuel enters the cab is really important. Fuel in the cab scares me. Its so easy to install an isolater to keep people safe and the fuel off the carpet...
 

cbarm

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OK cool...thanks for that!! I will check into it. As for safety, arnt we disregarding safety everytime we mingle with all the other idiots who cant handle their rig at highway speed?? haha
 

dgr

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Just remove the valve core, slip a hose over it and a hose clamp.
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That is exactly what I did do, without the hose clamp. It's just a silly way to get there. Opening the fuel system to check the pressure is a poor design. And being that as there is an auto-bleeder (at least on the later filter heads), probably not the way it was intended to be used.
ANY common FI test gauge available at parts stores for 35-50 bucks will have the proper connection you are seeking. Gassers use a schrader valve to on fuel rails. The nice thing about a proper kit, they usually have a bleed off line that drains the fuel off instead of leaving it under pressure when you disconnect it thus spraying fuel all over the place.

I'd suggest you pick up the correct tool and add it to you collection...who knows when you'll need to diagnose an issue with a gasser that has the same port, but if/when you do...well you can deal with it.

An inexpensive kit like this can save you or friends or family a lot of headache and costs associated with diagnosing a fuel problem

You must be registered for see images

....

That Actron kit actually comes with an adapter to go from our schrader to the larger schrader in the kit. Too bad the fuel pressure testing kits all seem to come with a 100 psi gauge. Makes them about useless for reading our lift pump pressure. Yup, I've got pressure. Can't really say how much because the sweep on the gauge is too small.

I'm going to look for either 1) A hose with schrader on one end and pipe on the other which is easy to find on European websites for bike pumps, "Flexible Connection with Metal End Schrader", 2) A presta to schrader adapter at the local bike shop or 3) The hose off a can of fix-a-flat.

This has become a mission. Maybe I'll replace my lathe and just make my own. Oh wait. Looks like a schrader tap is about impossible to find.

Maybe I'm just too damn stubborn. I know what I want. I can't believe that this isn't something that is off the shelf in some industry. I want an easy to use fuel pressure tester that doesn't require me to open my fuel system and provides an accurate measurement. Seems simple to me. I'm not going to install a permanent gauge under the hood. I think that's a really bad idea. Diesels sorta vibrate and the only thing stopping a significant fuel leak is a thin little soldered copper tube that's designed to flex.

I do appreciate all the optional ways you guys are throwing out. But does anyone know where the adapter I am looking for can be sourced?
 

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