I currently have an AutoMeter Sport Comp electric fuel pressure gauge working nicely in my '86 951. I have the sender connected to the front of the fuel rail.

My concern is that several fittings were required to fit the sender (without tapping the stock nut and trying to seal it with teflon tape or fiber gasket), and I'm worried about potential leaks and fire hazzard (which is why I didn't want to use the tapped nut set-up).

The fittings used, which all have proerly sealing seats, are (ordered from rail to sender):
1. 12mm x 1.5 globeseal (female thread) X 4-an male.
2. 4-an female X 4-an male 90 degree elbow.
3. & 4. 4-an female X 4-an male 45 degree elbow.
5. 4-an female X 1/8 NPT female.

These put the sender toward the passenger side of the fuel rail, pointing slightly toward the strut tower (but close to the rail). Since these are all swivel fittings, I can place them all in the best possible position and tighten them down. To prevent loosening, I applied some blue threadlock to all of the threads.

So, I feel that I'm tempting fate, as I would using the tapped rail nut.



The alternatives:
1. Use the existing 12mm x 1.5 globeseal X 4-an male fitting on the end of the rail, along with a 4-an 180 degree (u-shaped) tubular hose fitting with a length of braided hose running along the rail to the back of the engine, curving toward the battery box area, and ending with a 4-an bulkhead fitting supported by a fabbed bracket attached to the firewall or strut tower, followed by the 4-an to 1/8 NPT female fitting.

Still several connections, but without the weight of the sender/fitting assembly trying to loosen it.


2. Drill and tap the fuel rail (or drill and weld on a 1/8 NPT female fitting), attaching the sender directly to the rail. Not sure if there's room anywhere for this to work. Possibly at the back end of the rail, with a single 90 degree fitting (pointing toward the passenger side so that its own weight would tighten the connection, rather than loosen it).

Does anyone know if it's okay to drill the rail at the back, or anywhere else? Any problem with doing so?


3. Is it possible to take the pressure reading from the pressure line before it gets to the rail? For instance, from the hard line in the passenger wheel well? My thought here is that, since I'm about to replace the fuel lines (using braided lines and compression fittings to fit them to the hard lines in the wheel well), I could put the sender here using a tee fitting between the hard line and the braided line. Again, several fittings, but they wouldn't be affected by their own weight, and they'd be in the wheel well instead of in the engine bay above the exhaust manifold.

If this is a useable location to get an accurate reading, it seems to be the best option.



My preference is for #3, if that is feasible. #2 is my second choice, again if feasible. I know #1 would work, but I'd rather not have the extra clutter of the braided hose and bracket set-up. Any advice?

 

Here's what I've done.



I used a 12mm globe fitting for the rail and had an NPT fitting swaged onto a section of -4 teflon line. Installed an NPT tee fitting for the electronic pressure sensor and gauge and fastened it to the cam cover.