So I have been running down an issue with my 96 Discovery not liking to stay running on hot days. There is a list of things I need to do. Fuel pressure check, etc. It is coding for P0441, which, you know, seems related.

Glaring though is the fact that when I remove the cap off the fuel rail test port gasoline pours out pretty liberally. Seems like the Schrader valve is failing Can I just replace that valve or is this indicative of a more sinister problem with the rail?

 

Replace the valve, the fuel rail is just tubing.
The valve keeps pressure to the injectors, not relying on the fuel pump to be the only source of fuel pressure.

 

Dumb question.... does anyone know the 'official' designation of the type/size of schrader valve on the fuel rail?

IIRC it is a different size than say the schrader valve on the tires (or your kid's bike tires).

Knock on wood I haven't needed one, but someday I bet I will.

 

I don't know which one it takes, but there are alot of variations(I won't post who I work for, legalities), but it's automotive. These are just a few of the ac and fuel valves. They're cheap and easy to replace.

 

Thanks Sixpack. Yes, there are different types. I was hopeful that someone would know which type is in on our fuel rails and what that type/size is known as in the industry. Such that I could do a search for those key words and have some luck finding the right gauge without a bunch of trial and error.

 

@Sixpack, yes thank you! Followup question. Do you think this could be causing my stalling issues? I hadn't considered that before, but what you said about making the pump work harder..... and given it's only really a problem when it's hot not warm and only when there is a static load on the engine (like being in drive stopped at a light) but is fine under acceleration. I was getting set to check CPS, and IAC, and the evap, etc.....

 

It could be several things, but yes, a bad fuel rail valve could be the problem. Cheap and easy to replace.

I'll do some digging and see what I can find out, as far as which valve it needs, thread pitch, opening pressure, etc.

 

Can anyone confirm if there is a difference in the 3.9 and 4.0/4.6 fuel rail?
I can check and see which valve core is in my 4.6 fuel rail, as the upper intake is still off.

 

Basically, most auto fuel rails use a standard core size, the same as a tire valve. The difference being the seal material.
Put a tire valve in a fuel rail, and it'll work fine...for a little while, until the gas eats the seals.
The opening pressure is much the same, and low.
The valve core is really just a check valve, to keep the fuel rail pressurized(which is why a bad one could cause your problem zer0point).
LR does some strange things, but I can't see the D1 fuel rail valve core be any different than the D2.
Any auto parts store should have them, just ask for a valve core for fuel, same size as a tire core, just make sure it's for fuel.
zer0point and Walt, if you can't find what you need, pm me, and I'll get a couple headed your way.
I have some at home, I just needed to double check a couple things before I posted this.

 

I'll make the rounds tonight and see what I can find! Thanks @Sixpack577