How to Rebuild CIS Fuel Injection Porsche 911S! Teardown & Modification, Projekt Airkult Episode 24

Join me and learn how to assemble the fuel/intake system of a Porsche 911 with CIS/K Jetronic fuel injection. This is the third video of the CIS system:

Initial Teardown:
Airbox Inspection:

Vacuum Line Routing Diagram:

CIS stands for Continuous Injection System, and unlike modern EFI where the injectors pulse a mist of fuel at a specific time, this system just sort of mists fuel constantly into the intake runners, so the fuel vapor builds up on top of the intake valve, and gets sucked in on the intake stroke.

My system was functioning properly, so my goal was to document the CIS system, tear it down to inspect everything, and slap it back together. I also modified the intake runners by removing some extra bosses and mounting flanges, which should clean up appearance and help shed a tiny, insignificant amount of weight (I weighed it, 5 ounces!! lol).

Best Source of CIS Info on the Internet:

Resources I found Helpful:

Airbox Runner O Rings:

EGR Airbox Plug:

The BEST Engine Rebuilding Book for 911s

The BEST 911 Projects Book for 911s

The BEST source for information on 911 technical questions:

Music:
Song: Chaël - Sparks (Vlog No Copyright Music)
Music promoted by Vlog No Copyright Music.

#porscheCIS #cisfuelinjection #howtorebuildCISFuelInjection

[alexgross]

Dude these videos are awesome. I'm finishing a 75 911S rebuild right now! I tore apart the CIS almost 5 years ago so this video is an awesome cross-reference for my reassembly....so many hoses.

[davidpengilly]

Great video, looks like you are nearly there. Guessing you put the gasket between the input pipe and the cylinder head as that is crucial.

[TimeLapsesBaudet]

Video increible para quien quiera tratar paso a paso el CIS! Yo lo tengo desmontado y con este video quizas me anime a dejarla bien... Cuanto presupuesto se ha llevado en mangueras, etc?

[blackfish]

Great job! What sizes of hoses did you buy? I need all new. Also any layout on where the hoses go? love the Old Mulwalki

[Clubracer]

Great video, thanks. Did you replace the fuel lines from the fuel distributor? If so, where did you get them?

[ChrisMeirose]

It's like mating with an octopus...

[bertrandliang]

Nicely done. I am really considering getting rid of the CIS - seems to be causing issues with cold start that changing out the WUR and cold start valve haven't solved. Before you took your 911 off the road, how was the cold start?

[davidpengilly]

Also most will agree that cheap fuel hoses on a 911 is probably the No1 mistake to make. You cannot see if they are perished once the engine is in so you need them marine grade, maybe original Porsche parts is best.

[rogerjohnson]

Deff replace the plastic fuel lines, they make cheap braided stainless ones if cost is a concern; but those will burn the car in a heartbeat.

[udok.]

hi! nice Video. I have a '75 2.7s US finished. Motor starts well..work well...but... its a kind of spitting.... running out of round. i can upload a video. maybe anyone has an idea? Bosch injjection valves are new (maybe stored for some years!!!) quantity distributor is reworked as well...

[kedrickreddsr]

Great Video as always. I will be taking the engine/trans out of my 79 in a month or so. I may definitely have some questions for you 😎