Generaly speaking why is it that so many small displacement 4's idle SO HIGH for so long until warmed up? The EVO and the previous WRX i had were the ONLY cars out of like 30 that ive had that did this. Is it b/c it takes so long for the cars to enter closed loop mode?

 

I could be way off here but I think it has everything to do with the "automatic choke" function in the ecu and thats it. I don't believe open/closed loop mode is applicable in the this situation. My understanding is that it has everything to do with how the ecu was programmed to run during a cold start.

 

Ok thats not a bad explanation. It may very well be that.

 

I'm almost certain it is. Sorry if you already know all this stuff, essentially during colds starts much more fuel is necessary for a combustion. From what I understand, nearly 2-3 times as much fuel to keep it going during a cold start than if everything is warmed up. Essentially, automatic choke controlled by the ecu. If you more accustomed to just the bigger v-6/v-8's they do the same thing they just don't sound as high pitched. Again, I want to stress this is just my understanding of things and I welcome the correct info if this is not it.

 

That is a great explanation, I checked with a friend who is an ASE certified master tech and he said that is correct. Great explanation. Thanks

 

Only reason why i was asking was b/c my POS taurus SHO starts up then almost IMMEDIATLY drops to a perfect idle. Even when its cold out. I know some guys tried messing with their warmup cycle in the ECU Flash and some said it did nothing when they changed the values

 

In my experience the smaller the engine and the lighter the flywheel the worse they idle especially when cold, the computer is just setup to compensate for this.