How to replace an entire fuel line system front to back.
The existing fuel lines in the Porsche 944 Turbo were old, ratty, and even damaged. The rubber hoses, being over 30 years old, have a tendency to crack and leak as well. So it’s a good idea to replace it all, front to back. Check out the video below to see how we did it, or scroll further down for a quick step-by-step guide with full parts list and installation diagrams.
Part 1 of How to Build & Install Fuel Lines in The Porsche 944 Turbo
Part 2 of How to Build & Install Fuel Lines in The Porsche 944 Turbo
Multiple Issues in the Fuel System
We had multiple issues with the fuel system in our ’89 Porsche 944 Turbo, from clogged injectors, faulty fuel pump, bad gas, cut fuel pump power line (thanks to the previous owners DME relay bypass technique) and even a pinched return line which caused a high pressure issue.
Changes to the Stock Fuel System
We made several changes to the fuel system in our Porsche 944 Turbo. First, we installed a larger, more powerful Bosch fuel pump to meet the demands of future modifications. Additionally, we added modern Bosch injectors, which provide atomized fuel rather than a waterfall of fuel, and they fit seamlessly without requiring modifications to the fuel rail or wiring harness. However, these injectors require a 0.5 bar boost in fuel pressure, so we added an adjustable fuel pressure regulator for flexibility with future modifications. Speaking of the fuel rail, we found globe seal fuel rail adaptors that allow you to retain the stock fuel rail, so you don’t have to drop $350+/- on a new fuel rail.
Furthermore, we decided to remove the fuel damper, a modification many others have made. In the six months we’ve driven our Porsche 944 Turbo, we have not experienced any negative effects without it. This simplifies the fuel system by eliminating two connectors, one hose, and the damper itself.
Time to Get Started
We started by getting all of the correct parts and fittings. Note: The hardline adapter may not slide over your existing fuel lines if you choose not to replace the hard lines under the car. You can overcome this by filing the outer coating off of the existing hard lines so you have bare steel exposed. The hardline adapters should then compress properly. Carefully check afterward to ensure there are no leaks.
Here is a picture showing most of parts and fittings used in this install.
Products Used:
Products used in these videos:
| QTY. | Product |
| 1 | Injector Extension |
| 1 | 6AN Fuel Rail Adapter |
| 1 | 1/8″ x 2″ Aluminum Stock |
The Setup
After getting all of the parts needed for the job, we set up the old fuel pump and filter, we measured out the distance and relation between the pump and filter.
Once we had the measurements, we installed the adapters and fittings required on the fuel filter and fuel pump. We then mimicked the old fuel pump and fuel filter relation with the new Bosch 044 pump and filter. From there we were able to measure the length of the new 6an hose required for the fuel line assembly. More info on how we measured this in the video above.
We used a grinder to cut the hose as it melts the nylon while cutting; this prevents the nylon from fraying, which makes installing the fitting much easier. We highly recommend ensuring you get a quality hose, as the cheaper hoses, specifically cheap off-brand Chinese hoses found on Amazon, are likely to fail. This is one area you do not want to skimp on.
The End Result
This is what it should look like after the new lines are built and installed.
Fuel Line Diagrams
If you have any questions or comments drop them below!
Disclaimer! This is provided for information purposes only. We are not responsible for damages or injury incurred from following these instructions or diagrams.
Thanks for the great detail on the specs. Is there a reason you chose cupro over running the braided lines front to back?
Hey Chris, glad you found it helpful. Yes, I went with cupro as it is significantly more durable than any rubber hose braided or not. My thinking was these cars had metal lines from the factory that have easily lasted 35 years+, so why not replace them with a similar line that has even better corrosion resistance properties and similar durability to the factory lines. These lines will likely last my lifetime and is one thing I should never have to worry about. Rubber hoses, including braided won’t be nearly as durable as metal and are more suspectible to wear… Read more »