im wondering if anyone can describe the cold startup sequence that controls idle speed and help me pin point the sensor or issue on a 2013 3.5L EcoBoost
i live in PA so cold startups are a daily routine how ever the truck has developed an issue where it doesnt always start and go thru the high idle process
some times it does and some times it wont
but normally upon ignition the engine would initiate a high idle startup and tach to maybe 1500 -1600 rpm and spool up the turbos for say 15-20 seconds and then start to idle back down
this high idle has been coming and going at random lately even when the temps have been cold every time the truck was started
when it starts and does not go into a high idle it just sorta fires up and idles at around 1100 - 1200 rpm and doesnt spool up the turbos
i tried replacing the MAP sensor and thought maybe that was the issue because i do have 85,000 miles and have seen the oil residue inside the intake tubes and intercooler
i have sprayed the throttle body with seafoam several times because i do the regular intake cleaning that needs to be done to prevent the valves getting all gummed up
im looking for suggestions on what other sensor or sensors would effect the idle speed at startup so i have something to look at as i can watch most of the sensors
thanks in advance for any input
Brian

 

Not an expert but possibly the coolant temp sensor. My idle stays high until I begin to feel warm air from the vents. I let the engine warm for about 10 minutes or until the Transmission oil temperature has reached 90 degrees. By then, the idle has dropped to 1100 rpms.

let me ask this: Do you keep your foot off the gas pedal when starting it and while it's warming up?

I'm assuming it hasn't thrown out any visable warnings or codes since you didn't mention it.

 

Yes this is without any input from the pedal
most of the time i am remote starting
however if there is any input to the pedal the high idle is interrupted
also your correct there are no codes nor has there been
i doubt the issue pertains to a coolant temp sensor because the normal high idle doesnt last long enough to reflect any change in coolant temp
but like i said at thos point im looking for any and all suggestions so i will add i have not watched coolant temp and i will look at that over the weekend
i can watch most sensors right on my cellularized mobile smart device

 

A computer algorithm determines idle speed using information received from multiple sensor inputs. High idle is intended to get the engine up to temp as quickly as possible for the fluids and emissions but it will also adjust idle speed for electrical load and battery state of charge. You're trying to fix something that isn't broken.