Fast idle immediately after start

[andyrooski17]

Happened to me a few times over the last 2 days. Upon starting the car, even after a long period of driving shortly before (i.e. pretty sure a regen wasn't interrupted), the idle would be around 1000 rpm. Typically the idle is 800 when not in the middle of a regen. If I then drove a few miles and hit a stop light, the idle would be back to normal 800. This similar thing happened a couple times, but I never noticed it before.

Has anyone else experienced this? The car may have been sitting in hot sun before each start, but that's the only commonality I can think of. Toggling the AC seemed to have no effect.

Doesn't seem a big deal, just curious for some simple explanation from the crowd!

 

[WiszMaster]

If it's not a regen, any chance it's power draw, possibly low battery the alternator is trying to charge up?
Obviously much different chassis, but my '03 Eurovan did that extensively, if the rear blower would kick in high due to heat load, engine would rev for alternator and power demands.

 

[Southalabama84]

A couple of us mentioned noticing the same thing in another thread. Seems to be related with the AC usage. I never noticed it until warmer weather.

http://forums.tdiclub.com/showthread.php?t=440487

 

[andyrooski17]

A couple of us mentioned noticing the same thing in another thread. Seems to be related with the AC usage. I never noticed it until warmer weather.

http://forums.tdiclub.com/showthread.php?t=440487

Thanks! Now I remember reading that. It sounds almost exactly like what I experienced. One of the times i noticed it, I tried toggling the AC on and off, but it didn't seem to change. Perhaps when it's very hot, the compressor is doing something else regardless of whether you have the cabin AC on or off, or maybe the idle speed just doesn't react instantly to the AC button.

Anyhow, comforting to know others see it, and I haven't noticed it now that it's been cooler the last few days, so it's definitely something to do with heat.

 

[Ruso Turisto]

Mine did the same thin the other day, it was sitting in the sun all day +31C, must be related to a/c usage

 

[WildChild]

Mine always does that when the engine is cold. The RPM drops after a few minutes.