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Equivalent of warm up regulator (WUR)?

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My car (2002 C4S, RoW, tip) always struggles on cold starts.  By struggle, I mean that the revs tend to drop below idle and that when I press the accelerator, it behaves as if it had carbs with too much fuel being dumped into the engine (not much of a response, but after a few seconds, it takes off and works fine).  Besides the odd RPMs when coming to a stop and the lack of throttle response for 10 seconds after being pressed, I have noticed an extremely strong odor coming off the mufflers, something that does not happen when the car is warm. This behavior completely goes away after 5-10 minutes of driving.  It only happens when the car has been sitting for hours (8+).  The behavior is the same regardless if the car has been parked for a day or a week.


On older 911s, a failing warm up regulator, often called WUR, could be the explanation for this kind of behavior, but I have yet to find if we have an equivalent part on our cars.  I asked my local indy and he says that it is a common problem with these models here in Panama, and that the factory mechanics never figured out what was going on.  The local dealer, with their relatively new and inexperienced mechanics don't have any idea either.  I find it very odd, specially taking into account that temperatures here rarely drop below 25ºC (77ºF).


Any ideas?

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if your idle is dropping below spec (no HVAC) then you likely have carbon build-up in the throttle body and on the throttle butterfly.

Try cleaning the throttle body and butterfly with throttle body cleaner (CRC makes a good one).

Chances are that is all that is needed.

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Thanks Loren.  Will take a look at it again as I replaced the K&N air filter the PO had on the car with the factory one and back then, the throttle body looked clean.  I also cleaned the MAF sensor when I swapped out the filters.  Now that I recall, this behavior happened with both the K&N filter as well as the factory intake.

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Also do a throttle calibration by turning the key to the last position before crank with foot off the gas pedal and leave the key there for 60s. You should hear the throttle plate moving. Remove key afterwards and you're done.

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