dnwong

I know the fuel supply line to the fuel rail is fairly high pressure, but it looks like the return line from the regulator is much lower given the host clamps on both ends. I flipped the regulator around and will need a longer hose. Can I replace the return side with standard fuel hose from either Advance Auto or Autozone?

V2Rocket

Yes. But usually the auto store will sell "fuel line" and "fuel injection line" (high pressure stuff) in the same sizes so you may as well go for high pressure stuff for durability.

tempest411

Additionally, EFI hose is made from a different compound that is more resistant to the alcohol they put in most fuel blends these days. Gates actually makes a low pressure hose that is alcohol resistant, but generally speaking that's not the case.

951Tom

I'd recommend using the same high pressure line for the return. Reason being if a blockage were to happen the pressure spike could burst a lower rated hose.

jjeffries

Don’t take any shortcuts here; prime way our cars get destroyed is by fire from leaking fuel lines. Statement of the obvious: carb-rated hose in an injection system WILL fail.

A replacement set for a 924S/944/951 is eye-wateringly expensive ($600-$800), but what price safety? I’m overhauling an 87 924S from stem to stern and doing all new lines, sourcing then from Len Cummings in New Hampshire (well known to the air-cooled 911 crowd); he has all the correct (metric/DIN) fixtures and tooling. The factory is only offering certain of these nowadays; many are NLA.

For the engine compartment supply and return hoses, Rennbay also makes an excellent kit; whether theirs or Len’s, you have to cut the factory lines where they both go metal <> rubber hose.

if you’re interested, I’m covering this in my thread on Pelican...

http://forums.pelicanparts.com/porsc...itation-6.html

... starting on page 6.

But as said, please don’t pinch pennies and give the whole system a good look over first.

best of luck, John

Legoland951

Yes, fire has destroyed many 944s. I have personally taken apart no less than 10 burnt ones, seen a random 951 on the road burnt down to the ground when it came to a stop sign, and had a friend of mine improperly installed a fuel line to have his car burnt to the point where the front wheels melted around the caliper.

However, factory is not always best. The factory 85.5+ 944/951 uses a short fuel line on the rail that is a common problem that causes these fires. It is a DOT safety recall and Porsche replaced it free (used to at least). Use common sense. There is nothing special about a 944 fuel system that is any different than a modern high pressure FI system. Use FI lines and proper clamps.

tempest411

I'm sure a lot of us would like to hear from the engineers at Porsche at the time why they thought it was a good idea to plumb rubber fuel lines right above a piping hot exhaust manifold. Ferrari did something similar with a crossover hose joining two fuel tanks that right by a catalytic converter on the 308s.

jimbo1111

I recently replaced every single fuel line on the car. Including vent lines. Its a large undertaking, but worth the peace of mind.
I purchased every line that wasn't nla and then used fuel injection hose on the rest.
The return line near the tank is actually a crimp and then connects to the sending unit with a clamp. The crimp can be dremel off and a clamp can be used as a replacement. The return line is usually half the psi of the supply and a clamp will work.
I also used the rennbay kit for the fuel rail with the addition of using the old rubber coverings as an added precaution.

No Lag

I’ve been shopping for these lately for my S2. I’d like to stick to OEM parts, but I thought Porsche didn’t have them available anymore. Well I have found them and was looking for the other small lines to the fuel rail. Are the two lines over the cylinder head the main culprit for fires?

jimbo1111

Yes. The lines are over the headers and probably dry rot over time. Red headers and fuel don't mix well. If you want the original. I believe the supply is available through the dealer now. It was nla for many years. The return is just clamped. So a good fuel injection line will suffice. Rennbay and a few others make a good aftermarket kit.

jpuzas

Hi Guys,
I am doing the same thing with my 1987 944 meaning I am in the process of refurbishing the fuel system with all OEM parts. From the strainer in the tank to refurbishing the fuel injectors with new seals and plastic caps and all new hard and soft lines. My question is regarding the low pressure return line. It is a hard line and yes it is expensive $540 for OEM parts. The new version has a coupler in the middle. The old version spanned the length of the car. The part numbers are: Rear section that connects to a soft line that goes to the tank: 951-356-917-03 Front section that comes up through the wheel well to a soft line: 951-356-917-04 and then there is a "connecting piece" that sits about under the passenger seat to connect the front section to the rear section: 477-209-169.

Here is my question for you all since you seem to have done this already: The rear section routes up over the torsion bar rear suspension between the body and suspension. From my initial attempts, it appears one cannot fish it through that small space. What needs to removed to get that return fuel line routed through that small space? It looks like I can just disconnect the pivot on control arm then there looks like two bolts that hold the whole passenger side of the suspension to body. I am thinking that section could be under quite a bit of pre-load as well. Please share any insights you may have.

Thanks,
Jeff.

jpuzas

Bump due to no response yet.

walfreyydo

Have you seen this? Its a very thorough guide on how to replace your lines from the tank all the way to the engine bay.
https://www.deancent.com/porsche-944...d-and-install/
TLDR - you should use 3/8" cupro nickel hard line over OEM (cheaper and better)

And another great resource:
https://www.arnnworx.com/catalog/ind...d=17&chapter=1

Also, you may want to consider converting lines over to AN - cheaper and more fashionable than OEM lines (unless you are dead set on OEM). Lindsey, Larts Parts, and a guy on FB called Devon Lyons sells AN conversion kits (or you can do your own). Most of the OEM fittings are M16 I believe (see arnworx link), so youll need to put an adapter between the OEM and AN line.

Here is my S2 with AN lines (I put reflective tape around the feed and return for extra protection) including the feed and return from the dampener. At a later date, maybe this winter, I will convert the lines from the tank to the hard line with AN as well (outlined above in the first link). I do not think I will need to replace my hard lines (yet) but if and when I do I will follow the same method.

jpuzas

Thanks Walfreyydo!
I looked at both resources and unfortunately they do not address routing the lines over the torque tube. The first reference used the bendable properties of the AN lines to fish the line up and around the torsion bar. The second reference used the OEM lines but did not discuss the routing over the torsion bars. I have already purchased the OEM lines so I am somewhat committed at this point. I did see on Lindsey Racing that they use braided steel for the return line which easily bends around the torsion bar suspension. So this is a good bump.

So here is my question again for convenience: The rear section routes up over the torsion bar rear suspension between the body and suspension. From my initial attempts, it appears one cannot fish it through that small space. What needs to removed to get that return fuel line routed through that small space? It looks like I can just disconnect the pivot on control arm then there looks like two bolts that hold the whole passenger side of the suspension to body. I am thinking that section could be under quite a bit of pre-load as well. Please share any insights you may have.

Thanks,
Jeff

walfreyydo

It sounds to me like you will need to slightly lower the rear suspension torsion bar tube. This can be done by removing the main bolts and supporting bolts holding the torsion tube carriers as well as the banana arm connections. From there you should be able to pivot the rear suspension down as it hangs from the shocks. You may need a couple of jacks to support. You can only lower it so far before the brake lines need to be disconnected but hopefully youll gain enough clearance before needing to do so. There are many guides out there on how to lower the rear suspension so I wont go into those details. I have circled the connections which need to be removed for you to be able to pivot down the rear suspension while letting it hang from the rear shocks. With the rear of the car lifted it should not be under any pre-load.