Is my WUR working in reverse?!

[belfry]

I have a US sourced 1982 sc with 33,000 miles. I have spent the last few months trying to sort out a high idle problem.

I have replaced the Warm Up Regulator, and the Aux Air Valve, and followed the vacuum hoses with propane but I have an issue where the car will idle at 900 rpm when cold, but will rise to 1,200 after about 5 minutes! So then I adjust the idle down to 950 rpm using the idle adjust screw, but next time I use the car that day the idle is now too low and will stall when coming to a standstill.

Could the WUR be working in reverse?? Or the AAV??

I am wondering whether to try taking the 12v electric plug out of the WUR to see if that helds.

I have had the mixture checked and it is running fine in terms of CO2 and MO2. I have also checked the timing and adjusted the idle.

[Jeff NJ]

Check to see if you have 12V to the AAV and the WUR. Replacing them does no good if the heaters aren't working due to a lack of power to them.

[dhanl82]

A few thoughts,

Even without 12 volts the engine block will eventually warm the wur to what ever psi it is setting for warm control pressure.

If you disconnect the outer hose to the AAR, you can look inside with a flashlight and mirror to see if it is open with cold engine and closed after 4-5 minutes after engine started.

I would strongly suggest that you get some gauges to check your "system" and "control" fuel pressures - until you take a look at those you really will not know what is going on.


There are a lot of great threads on this forum that have addressed similar problems, they will be of great help to you in determining the cause of the problem and in getting educated on CIS.

Dave

[john walker's workshop]

Be sure the frequency valve system is working before messing with adjustments on 80 - 83 SCs.

[Coastr]

Try unplugging the decel valve when it is idling high and see if revs drop. Also is it persistent in every startup or somewhat random?

Also take John walkers advice above.

[T77911S]

check fuse 18

did the person that checked the CO know what they were doing as far as CIS and Porsche goes.

check for power to the WUR.

[RarlyL8]

Eliminate the easy stuff first. There are many vacuum hoses on the US '82 SC, warm the engine then block them off one at a time. If the idle drops back on any of them check the components controlling that path.
If all OK verify fuel pressure.
If Ok go to electronics.
Don't adjust anything, fix the problem.

[wreckah]

if you are sure the AAR (the thing that adds air at cold start) is working, check this out:
CSV flange (911-110-264-00) Alert......
that wrong part will block the whole path to AAV, decel valve, etc, making them not work at all.