Type CIS
 

I have a 1975 911 targa with an 2.7L engine (911S).
I have some starting problems. And I think the warm up regulator (WUR) is not functioning anymore.
The previous owner told me he had replaced the CIS system from an 3.0L.
Can anyone tell me how I can find out if there is an 3.0L or an 2.7L CIS on it?
Thanks.

Post the part number on your WUR.
Some pictures would help too.

There's a great cross-reference of component part numbers listed here:

CIS Primer for the Porsche 911

pete 3799 What good will this pictures doo?
I can post the WUR number 0438140009 this from a 2.7L, but how can I check the rest of the CIS is also an 2.7L or perhaps from an 3.0L?

Dont know if this helps,
0438100004 or 006
Are Fuel distributors numers that fit my 2.7(74)

Alex, I am new to this Porsche cis hand throttle business. Is this a new car for you or have you had the car awhile and familiar with it start up and warm up? I may be off base here but my car started fine just using the throttle lever until the cold weather got here. Now I have to touch the gas peddle just slightly with the lever to get it started my parts are intermixed, 74 car, 78 3.0 litre. And I cis from both. I am not sure if this would be right for your car but when I first got the car I was afraid to hit the peddle until the car warmed up. I do have a pop off valve. Please wait for more advise I am only relaying my experience. Also post pictures. These pelican guys are good they can tell what you have by looking at pics. If you can remove the Air cleaner as well. I forgot the name of the post but they helped me last month. Looking at pictures, amazing.also what makes you think you wur is shot? I was afraid of this to but was just a vacuum leak. Symptom?

The number on my fuel distributor is 0438100006.
Is this probably from a 2.7 CIS?

wur cis
 

p
1. to get you car started you need the cold start valve to work, this works when the throttle lever is pulled up or as on my car ( a 75 has been modified so that the CSV works when the starter is engaged and stops when the starter is not engaged.
so first thing to check is the cold start valve.
How? it is a pain but you can fashion jumpers to fit on the valve solenoid, when you jumper it you will hear the gas being injected (if the fuel pump is running). If the valve works then check voltage at the wiring connector when the key is turned to start. You should have 12 vdc to ground.
If you have 12 volts when the starter is engaged and your cold start valve works then you may be soon on your way to fixing the problem.

2. the ground wire from the CSV goes to a device called a thermal time switch(TTS) If the car is cold the TTS lets the CSV work by grounding the circuit which energizes the CSV if the key is in the starter (active solenoid) position. this device should be closed to ground when the car is cold and open to ground when the engine is warm. If this device is not close to ground when the car is cold then i would guess that it is faulty. The wire from the CSV to the TTS is i believe brown.
3. Get a set of jc whitney cis pressure testing gauges. and fine tune your cis.

4. My 75 has a yelllow wire that is connected to the starter solenoid and goes to the CSV + side. the brown wire goes to the TTS.

If the injection has been replaced with a 3.0L system then you would not want to use any hand throttle! The 3.0L has a cold start injector that should get the car to fire and run with just a click of the key!

You have not listed the acual issues you are having ie cold start, warm start, cold idle problem? FYI 90% of all 3.0L issues are directly related to vacume leaks between the fuel distributor and the throttle body!