Identifying this cap screw

[RANGermanGuy]

Hi,

I just purchased a 1999 Ranger 3.0 2WD
Can anyone help me identify what this little plastic cap screw is called and what it does. I believe mine is leaking.

 

[Roert42]

That’s a cap for a shrader? valve.

Looks like it is on the fuel rail, but hard to tell.

The cap doesn’t seal anything, just to keep dirt out of the valve. If something is leaking you an issue with the valve.

 

[Uncle Gump]

Looks like the fuel pressure service port.

 

[Bgunner]

That cap is to cover the Schreuder ( <-- may have misspelled that) valve on the fuel rail. The valve is used to check fuel pressure in the fuel rail. That valve works the same way as a valve stem on a wheel.

 

[Uncle Gump]

I was having a hard time with location too...

It's either fuel pressure or an a/C service port.

 

[Roert42]

The more I look at it the more on positive that it’s on the fuel rail. You can see the valve cover just below and you can see the pipe that crosses over in front of the intake.

 

[Bgunner]

It is for sure the fuel pressure service valve. I have the same one on my 3.0L, even the cap is the same. You can see the FPR (fuel pressure regulator) just to the left of it.

 

[RANGermanGuy]

Thanks for all of the reply’s, very helpful! The man I purchased the truck from said I’d need to replace that valve as it was leaking. If it “was” broke, would I have a leak coming from that valve?

 

[Bgunner]

If the valve goes bad it will leak while the engine is running OR after the pump runs for the 2 seconds right after key on engine off. (edit: if this leaks it is usually accompanied with a hard to start symptom after the vehicle has sat for 8+ hours.)

To check if it is leaking remove the plastic cap and look to see if it is wet or fuel is dribbling out while engine is running. IF these signs are not there then the valve is fine.

 

[dvdswan]

I asked the cap what it wanted to identify as and it told me it want to identify as a Schrader cap.

 

[Ranger850]

I asked the cap what it wanted to identify as and it told me it want to identify as a Schrader cap.

I'm not sure you can call them "caps" anymore. I think the term is "threaded lid" or " Twist-on Cover".
Apparently they want to separate themselves from these guys