Mark R.

Does anyone know where I can procure one of these adapter fittings (see pic below).
It’s a machined adapter piece that makes the proper connection to our fuel rail access port.

I have no desire to leave a fuel pressure gauge permanently installed on any of my cars.
But I do need one periodically for checking the integrity of the system and troubleshooting.
And I already own a couple of really nice fuel pressure gauges in my tool arsenal.
They both came with Shraeder valve connections on them, but I know I can adapt them.
So this little machined hex shaped adapter piece is EXACTLY what I need for that.

Anyone..? Thanks!


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Mark in Atlanta

87 S4 Grandprixweiss Auto w/LSD (Daily Driver Since 2004).
88 S4 Silbermetallic 5 speed w/LSD (Weekend Driver Since 2003).
84 S Schwarz Auto w/LSD (Sold in 2007 - Daily Driver 1997-2004).
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kmascotto

Hi Mark, I picked mine up at Lindsay racing and it looks just like your pic.
http://www.lindseyracing.com/LR/Pors...-FPGK-944.html

Eplebnista

What is the size/thread pitch of the fitting?

kmascotto

don't know...but it fits the 928 fuel rail.

davek9

im sure one of our known parts vendors would have these on hand, I always try them first.

Mark R.

One would certainly think that, but be careful about being "so sure"...
I've checked and come up empty so far. Someone please correct me...

It appears the thread is a fairly standard M12x1.5.
But it's the internal ball shaped feature that is the key.

The link posted by kmascotto includes the correct fitting (pic below).
I will check to see if they will sell just the fitting...

Mark R.

OK, so Porsche placed this fitting on the end of our fuel rails specifically for the purpose of giving access to the fuel system.
I think we would all agree on that. And based on that, here are the questions I have:

1 – Is there a Porsche specific tool part number for whatever pressure gauge Porsche intended to be connected and used?

2 – Is there anyone that knows the proper industrial designation for this particular type of fitting?
That information alone would help immensely in the effort to research and source the correct components to interface with it.
I’ve searched (both this site, and others), and have yet to be able to locate any designation (like SAE, JIC, DIN, BSP, ISO, etc.).
I believe both of the pictures I posted above are examples where people have machined their own version of the needed fitting.
It seems incredible to me (and I’m not giving up yet) that there’s not a standard fitting we can procure to use for this purpose.

Eplebnista

I sent Lindsey Racing an email inquiring about the cost for the adapter alone.

Here is what they sent back: This is so very typical - about 2.5 to 5 times what it should cost but still cheap enough to tempt you to say WTF I will pay the high price.

Mark R.

Yes. I received the same answer. And you're right. I will probably just pay their price and move on.



But I really just can't imagine that Porsche wouldn't have had something more standard in mind...

jcorenman

Check with Roger- he had a bunch made at one point.

I am sure that Porsche offers a fuel-pressure test kit with the appropriate fittings (and an appropriate price tag).

Rob Edwards

The Porsche factory tools list contains P378, which is for L-jet cars. I've never seen mention of an official fuel pressure gauge for S3+ cars.

Arnworx sells a fuel pressure gauge with (I think) the proper fitting on it. $30, but the gauge is included for free:

http://www.arnnworx.com/catalog/inde...1#.U0XCGvn0d8E

Eplebnista

Very nice Rob, thanks.

Arnworx also has an adapter for the test port for $16:http://www.arnnworx.com/catalog/inde...roducts_id=197

If I can finagle a way to connect this adapter to a GM test port schrader valve, I will be in business. Of course, its pretty hard to walk away from a dedicated fuel pressure gauge for $30...

ROG100

I stopped selling them so I could sleep at night - after one of the gauges capillary tubes burst and caused a fire on Randy's car. After that we sold them with a caveat that they must be only used for test purposes - then I saw them permanently attached to a couple of cars - end of that.

Mark R.

I started with Roger first as usual. He currently has none available...
(as a matter of fact, that's his picture in the original post above).

Thanks Rob! That's an excellent lead.
So digging further, it looks like it utilizes an AN fitting that's referred to as a "globe seal".
Outstanding! Thats exactly what I needed. Thank you!

Rob Edwards

Although the P378 is listed specifically for the L-jet cars, the picture on page 24-8 of the WSM shows it attached attached to the fuel rail of an '80 (or so). The cap nut 928 110 475 04 used on L-jet rails is the same all the way up through the GTSs, so I'm guessing it would work on the fuel rail on any '80-95 car.