[Monkey Wrench]

what you can see by driving your car with the fuel pressure gauge connected is any dip in pressure. lets say your fuel line or the screen in your tank or your filter is partially blocked

under that condition you may find that because the fuel pressure regulator is doing its job, you get a satisfactory reading as compared to whats expected. now if you drive the car flat out up a hill and see the fuel pressure drop then you would know the fuel delivery rate is lacking and as a result could see a drop in fuel pressure..

I do not think you are seeing any of that so I'd say you are done checking that. That's not to say you couldn't have some other issue like a air leak or a dirty or plugged up injector. the injectors each have a little gasoline screen and can be back-flushed. you can also look at the spray pattern or check if it has a leak or is stuck closed.

you can do that if you pull the fuel rail and watch but many will not recommend it as you are then atomizing gasoline and could cause a fire or explosion.

a stuck open injector will cause fuel pressure to drop quickly but your gauge seems to be holding pressure over some duration of time. if it did leak, the fuel in the fuel rail would continue to flow into a cylinder, and then when you started you'd get a bunch of white smoke , excess fuel in the the cylinder clears itself.

with a leaky injector, you'd see the gauge drop in pressure due to the leak so the gauge is a safer way to see if the injectors are able to close properly.

if the injector sticks closed it basically won't fire in that cylinder and youd be running around with an engine that lacks power, won't idle well, but probably still runs.

when you pull the plugs do a side by side comparison , if you ever see any drastic differences you can look for why that is. if they all look tan colored and OK then I wouldn't suspect a fatal issue with the injectors


an injector could spray but maybe with a bad spray pattern, much like a old spray can with a half plugged nozzle. that may be harder to pick up on

Im just replacing the 6 injectors in my ford van, it was running terrible so I put a bunch of parts in.. access is not good, I had to spend a lot of time removing the throttle body and upper manifold.. Its not so hard to gain access to in a porsche.

i'm hoping that installing reconditioned injectors will help my van run better. I chose not to clean them myself because access is very time consuming , otherwise I'd check then and clean them myself.

I think what surprises me most is that they seldom actually fail, there are lots of 30 year old cars running around with no new injectors.
My 944 sat so long the gas was basically turned into goo so I wont crank it and I will clean them and flush the fuel system before I even try to crank the engine..

I have a new filter pump ready and may take the fuel lines out and replace most of that..

the OEM fuel lines can be expensive, and there are aftermarket parts that will fit. some use a type of anodized aluminum fittings, some buy OEM or there is a guy on this forum that can make them up to look OEM,

I have a hydraulics shop that i take hydraulic lines to and have them crimped, I believe these are metric lines. I called and they told me they wont work on fuel lines, only hydraulics.

someone here did a nice write up with all the part numbers to convert to anodized aluminum fittings and there is a marine fuel hose. I bought some samples. it is a really thick heavy rubber fuel rated hose with an inner plastic core where the fuel runs. I think those are perfectly adequate. I do not believe it is metric line but may fit the type of fittings youstd need to convert it.

if the car is very original you may want OEM. I'm swaying to replacing mine with the aluminum fittings and marine grade fuel like. I contacted a local fittings place. I was planing to remove all the fuel lines and let them help me order them so I can get all the correct parts.

the diagram with the part numbers is a good start, most will be identical parts, bear in mind there were some changes, so you want the correct stuff.

on some cars the fuel lines run above the hot exhaust manifold, on mine they do not , you can consider relocating them. the problem is , that if there is a fuel leak. it can cause a big nasty gasoline fire and wreck your whole day. this has happened with other 944's


I think if you put a tap in the line before the dampener, when you closed it you may sense some noise emanating from the fuel line. I don't think you'd see any difference at a gauge or see much difference in performance..

over time fuel line vibrations could possibly cause some undesirable metal fatigue.. whether you'd ever see a problem with that I dont know, but when things vibrate there is stress upon the metal. repeated fatigue could possibly cause metal hardening and cracking like what happens with airplanes. It might be unlikely to see a failure, perhaps you'd hear the noise and it may be slightly annoying.

I suggest keeping yours if it hasn't failed. a new one might look better cosmetically

my 66 volvo has a similar part in it's braking system, its a piston with a spring behind it that can move somewhat if I stomp on the brakes and it is mounted underneath the car.. In its' lifetime, no leaks, no failures. single circuit braking system too.