urslo4n8

iTrader: (5)

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?

boozeup&riot

iTrader: (12)

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.

urslo4n8

iTrader: (5)

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

boozeup&riot

iTrader: (12)

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.

KeithD

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

urslo4n8

iTrader: (5)

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

cfdfireman1

iTrader: (11)

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.