High Idle just after Ignition

Hey guys. Looking for a little troubleshooting advice. recently when I turn the engine over the RPMs rev up like usual but drop down only to 1500. It will sit there until I pull out of park, essentially until I allow the engine to have some gas or what not. It then drops down to about 900 - 1000 rpms.

 

I recently had this issue with my jeep. I took out the throttle body, cleaned the MAP and TPS, then 'Seafoam'ed the lines. The High Idle disappeared but now I am dealing with a separate issue. Jeep now likes to accelerate on its own:eek:.

 

But I digress. TLDR = Subaru idles at 1500 RPMs after ignition. Any idea why?

Warmup

Normal.

 

Invar posted the attached picture in another thread, and from my experience I think it's probably pretty accurate.

 

You live in Texas where the temperatures don't get that cold. You shouldn't be as low as 500 though.

 

Here's what a stock idle table looks like:

I believe the top table is a "high load" table when AC/blower and other things are on. Bottom table is a "normal load" table.

http://legacygt.com/forums/showthread.php/high-idle-cold-p4253190.html#post4253190

Seems so odd that its normal, just sounds loud and obnoxious. Thanks guys.

Are you saying it happens even after the car has been driven, shut off for a short while and started back up, like when you put gas in the tank...or run into a store for a few minutes ?

Honestly I've only noticed this when I start it up for the first time. After that I am usually running through the checklist of what I left the house for so a quick shut off, run in the store, start back up goes unchecked by me.

 

I will make a note to listen and look for this same "warm up" after a short down time.

Sorry, how old are you ?

 

All cars rev high for a few minutes until they warm up, its called the automatic choke.

sorry, how old are you ?

lol

Yea because my age has a lot to do with my question.

 

I asked because it sounds odd after it turns over. I also noted in the OP how I just went through a High Idle issue with my Jeep. It too rev'd at 1500 constantly and the CEL came on returning a High Idle error code.

 

My apologies if that same symptom causes concern in my daily vehicle.

 

 

 

Thank you everyone else for alleviating my concerns.

I asked about age becuase I have seen young drivers ask about white smoke coming out of the exhaust pipe in the morning. That's normal, the same as the car idles at 1500rpm while its warming up.

 

Seems not every parent teaches there children what is normal as the car starts up.

 

Oh, is your name Dick, I didn't realize that.

It seems to me if one really had an issue with a high idle, one would pay more attention to when it happens, but as you posted earlier, you don't pay attention to it unless its the first start of the day.

 

You could have answered your own question.

 

 

 

 

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Chances are subaru is doing it for emissions purposes to heat up the catalytic converter quicker, since they are not very efficient when cold.

^This. And, if you have your HVAC system is in the "on" state, with the AC compressor running, then initial idle is going to be even higher. See table above. In order to achieve PZEV or even LEV status, those catalytic converters need to get hot and quick. Higher RPM, initially, does that. Once the ECU senses that the OP Temp is where it should be, then Idle will drop back to normal position/condition.