Since your fuel pressure does not change from cold to warm, you clearly have a problem with the wur, as you suspected, and yes, the wur should still "work" from the heat of the engine.

Now, I'm not experienced on the setting of the air/fuel mixture in the fuel distributor but given your pressure is so low--1.4 bar--I'd suspect someone adjusted the fuel mixture screw to lean out the air/fuel ratio during warm running. Running an engine at 1.4 bar while warm would certainly provide an overly rich fuel delivery that likely show up as bogging down or black, sooty exhaust if all other components were in spec. If the fuel a/f ratio was set to lean the warm engine, the result would be the car runs well warm but the mix is overly lean during cold start. This could be in addition to an air leak or faulty component that you may have.

Again, this is just my interpretation of a possible problem. Perhaps someone like Tony or Paul can confirm or correct the possibility as I'm not sure if the mixture screw air/fuel setting is independent of the control pressure.

We need closure, are you getting closer to solving the cold start issue? Make sure you have a WUR with internals. :)

New airbox and no vaccume leaks!! big improvement but not quite right. New check valve also.

The warm up regulator that I bought here in the classifieds had no internals so that is why the pressures did not change. $125.00 down the drain.

I put another regulator on and the pressures are now were they should be cold and warm. I did tap the pin to get a little lower presure , but within the temp range.

Still stumbles for about 10 seconds then starts to find it way to 900 rpms then after a minute or so the RPM's come up to around 1200.

I am starting to give the AAV the stink eye. I'll stick it in the frige next.
Thats the update.

Ron,

I have the exact same year car as you, and the exact SAME PROBLEM! This thread is very timely :)

Can I ask you one question - how is driveability once the car warms up? I am fighting an issue that I'm thinking may be related to this start up problem. After the car begins to warm up, say 10 or 15 minutes or so, and when I start getting on it, I seem to have a power loss and the motor seems to DRAG when I let off the gas. This happens intermittingly. It's like the parking brake goes on, that's how drastic it feels.

I have a pinched oil line and thought it may be a oil cooling issue, but last night I nearly burned myself on my trombone oil cooler, so I know the oil is getting to it and being cooled. Plus my oil temp gauge is normal, builds normally, nowhere near the red in these temps (15 deg C).

I'll stay subscribed to this thread and let you know if I find something that caused my start-up issue. I have a stainless steal airbox that a PO put in. Very interesting device. I'm just starting to look for leaks now as the car is new to me. Removing my oil filler cap barely affects idle. Still need to check my WUR and CPs, etc.

Cheers,
Dan

If your oil cap barely effects RPMS you have a air leak some where. It should drop a couple hundred RPMS. My car did the same as yours with a bad air box.

My car ran very well after the cold start issue. Starts right away when warmer than stone cold.
No power loss at all.
Just installed a new air box because as I and everyone else suspected it was cracked. Along the bottom three intake port openings were it can't be seen installed.

Ron,

I think we are fighting the same fight.

http://forums.pelicanparts.com/porsche-911-technical-forum/668088-cold-control-pressure-wur-hard-stop-cis-experts-3.html#post6687440

Michel