Hunting idle
 

Hi all,

I am suffering cold start issues and hunting idle on my '83 SC. When I start the car it stalls and does not hold idle unless I step on the gas pedal. I have also some hot starting issues, although they are less frequent. The car is a stock '83 SC with 160.000 miles on it.

I am thinking the WUR is the main suspect here. What do you think? Any other options besides replacing it ($$$)?

Thanks!!!!! SmileWavy

Idle Control Valve?
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/481223-idle-control-valve-testing-procedure.html

Aside from the above, the WUR is probably the most likely candidate, along w/ vacuum leaks and an incorrect mixture setting.

An idle that hunts rhythmically (like a sin wave) in a CIS engine is usually from a too rich mix. One that drops and then comes quickly back up, holds and then drops is usually from a too lean setting.

You have to determine if the mixture is just set incorrectly, or are there other things wrong that someone has tried to rectify by changing the mix.

A CIS fuel gauge is an important tool in finding out if your WUR is OK. An AF (air/fuel) meter is good for checking the mixture.

I had this exact issue with my car a few years back. It was the WUR. I used the CIS fuel pressure gauge set to prove this out before ordering a new one. The gauges are under $100 and well worth the money if you plan to play with CIS cars. On a side not, after I replaced the WUR I took it apart and found it was full of junk. I cleaned it out and reassembled it. About a year later I sent it to a friend that was having a similar issue with the same part number. It fixed his problem.