injector lines "how to" please

[michael pagano]

I was looking at my fuel injection lines on my 1976 911s CIS car and they look mighty old...In some places they look like they could crack right off. What is the procedure for replacing these and what size tube do i need. Do i just slip a new tube on the existing fitting or do i glue or clamp it? Mine are not clamped or anything but that cant be very strong...Also how much of a pain is it to change my vacuum lines while in around there? Thanks in advance.

[HarryD]

If your plastic CIS lines are ok, DO NOT REPLACE THEM!

It is difficult, if not impossible to get the correct replacement tubing. The Aftermarket Nylon Tubing currently available on the market has too thin of a wall thickness and will result in injector pulsing. Read this thread for more information: CIS misfire

To install, the lines are heated slightly and pressed on. IMHO, the connection is quite strong. My 1973.5 has these lines, which are original with no issues.

[Scott R]

The lines are probably fine, it's the rubber exterior that's most likely falling off. As said above, don't replace them. If you're concerned about the aesthetics of it get a used set of steel lines.

[michael pagano]

good to know, thanks.

[DSouth]

Does anyone have a source for replacement rubber insulation for the plastic lines?

[oneblueyedog]

I took my rotted, crumbly rubber sheaths off in 2000. No problems since then. I would think you would have to redo the nylon lines to slip the sheaths on them. I only replaced one line that a PO has kinked. I don't even think that was a factor. You use a soldering gun to melt the line over the barbed ends, never a knife. You will slit the barbs and risk a leak if you use a knife. The nylon line is pressed on the barbed end. I got the info for the line replacement here. There is a tool to install the nylon to ends. I rigged a set of pliers to do the same thing. It takes a lot of force. It's essential to use the correct ID nylon tube. I have forgotten the ID but you will find it in a search.

I suggest leaving them alone. You can slit some vac tube and hide the seam from sight if you need the protection of the sheath. I have r and rd things past them countless times and the lines have never kinked. I read somewhere that it was to dampen pulses. Only pulse I get is a rise in mine when I go to red line.

[LM3929]

There is a fellow here who sells the correct lines and the tools "unobtainium"


Lorne M.

[E Sully]

No idea how good they are, but found it during a search.


J2 Precision Hose*::*'CIS" Fuel Lines*::*" CIS ' CONTINUOUS INJECTION SYSTEM REPLACEMENT FUEL LINES