CIS trouble - low idle during warm up
 

Hi guys,

I have a friend who have some problems with his car.

On cold start, the car is doing some yoyo during the first 2 minutes. After that, the iddle gows down to 500 RPM and slowly reaching 950 RPM.
When the car is hot, it works preaty well.

Here is the car configuration :
- it's a 3.2 with a 3.0 SC european engine
- the fuel distributor came from a 188 HP engine
- the Wur came from a 204 HP engine
- the auxiliary air valve closes within 8 min
- the engine was recently rebuild with 964 cams and Malhe 97 mm pistons
- all the CIS parts were rebuild and setup correctly and or tested separately
- the mixture was setup to 2.7
- all the ignition parts are also new

We sticks with this problem for a while and couldn't figured out was causes the issue.

I hope I made myself clear enought :).

Thanks a lots for your help.

cheers

CIS troubleshooting.........
 

I like to help you but your information is too vague. Please provide the following:

FD ID Bosch number
WUR ID number
AAR ID number
What do you mean mixture set @ 2.7?
What are your fuel pressures readings (cold, warm, and system)?
How is the integrity of the vacuum system? Did you test it?

Keep us posted. Thanks.

Tony

Hi Tony,

Thanks for your help.

here is the information you asked :

FD ID Bosch number : 0438 100 031
WUR ID number : 0438 140 089
AAR ID number : 0280 140 201
What do you mean mixture set @ 2.7? 2,7% measured with a gunson gastester
What are your fuel pressures readings (cold, warm, and system)? Cold = 1b @7° celsius, Warm = 3,1b without vaccum (3,8b with vaccum), System = 4,5b
How is the integrity of the vacuum system? Did you test it? Yes, everything seems to be fine

Thanks :).

Hi guys,

After few research, I foudn something that my be our problem :

http://forums.pelicanparts.com/porsche-911-technical-forum/893455-1981-sc-cis-low-idle-wrong-wur-6.html

I'll keep you in touch if it's that.

Cheers :)

You also need to check the AAR and make certain that it is opening and closing properly.

Actually, He already tested it. When it's cold, the TAA is open and i took 8 min to close.

Have the timeline for the FP as well ?