Cold Start Excess Revving Incident

[FRSBRZGT86FAN]

Originally Posted by go_a_way1

^ This hahaha!!

I have a remote start for a reason

Originally Posted by Tcoat

In the real cold start world:

Start it
Let it drop from high to mid idle
Put in gear and drive it away
Take it easy for 5 minutes or so of driving to bring cats, bearings, oil and fluids up to semblance of earth like temperatures
Let er rip


The only reason I would let it sit and idle for 5 minutes or more is to allow the heater to come to temperature and blow through the defroster before tackling 1/2 an inch of solid ice all over the car.

Tcoats idea is better than remote start, two years ago we had record cold in PA getting to below 0 Degrees Fahrenheit on multiple occasions and way colder with wind chill. I did a little experiment and timed how long it took to get my 2014 Rogue to proper engine and oil temp levels as is displayed on the multi controllable display in the gauge cluster. Around 13.5 minutes at idle to get coolant and oil to temp on idle, and literally 6 minutes to get coolant and oil to temp by driving around and less mpg wasted because I was driving off in the morning to work/school rather than idling away.

[go_a_way1]

Originally Posted by FRSBRZGT86FAN

Tcoats idea is better than remote start, two years ago we had record cold in PA getting to below 0 Degrees Fahrenheit on multiple occasions and way colder with wind chill. I did a little experiment and timed how long it took to get my 2014 Rogue to proper engine and oil temp levels as is displayed on the multi controllable display in the gauge cluster. Around 13.5 minutes at idle to get coolant and oil to temp on idle, and literally 6 minutes to get coolant and oil to temp by driving around and less mpg wasted because I was driving off in the morning to work/school rather than idling away.

My car will see -35C without windchill a number of times each winter so I let it idle lots and my gas milage is completely crap but I don't care as it is still crap in the summer hahaha. I didnt buy the FRS for fuel economy

But you are right it warms up much faster if you drive it

[FRSBRZGT86FAN]

Originally Posted by go_a_way1

My car will see -35C without windchill a number of times each winter so I let it idle lots and my gas milage is completely crap but I don't care as it is still crap in the summer hahaha. I didnt buy the FRS for fuel economy

But you are right it warms up much faster if you drive it

Lol wasn't directly referring to this car mpg wise anywho I get 17 MPG because I constantly push it in even the slightest curvy situation lol

[Manic]

Originally Posted by steve99

Heaps of stuff happens at initial cold startup

Different compensations are applied on hot start

see diagram below

On Cold start

Fueling is enriched to heat cats, fast idle and retarded timing (thats the noisy bark at startup)

Different offsets to MAF (fueling) are applied depending if in neutral or in gear.

Different idle depending on coolant temps.

If you load the engine so it drops below its idle target of say 1800 rpm in initial phase the eCU applies more compensation to try to hold the idle at 1800, so if you then depress the clutch it will idle above 1800 for a bit , before settling back to its target idle speed. It a bit like anti-stall.

Idle targets A through to I are applied throughout the startup/warmup phase depending upon time since startup I suspect and coolant temps ,probably other factors as well

Best let it idle for a minute or so till idle settles to about 1200.

Awesome information! Thanks for the write up, really helpful. I'll just give it a bit more time to warm up while these temps stay the way they are.

[Tcoat]

Originally Posted by go_a_way1

My car will see -35C without windchill a number of times each winter so I let it idle lots and my gas milage is completely crap but I don't care as it is still crap in the summer hahaha. I didnt buy the FRS for fuel economy

But you are right it warms up much faster if you drive it

If I read yours right you do that to warm up the passenger compartment not the engine anyway. It is the difference between warming up the car and warming up the drive train.

[go_a_way1]

Originally Posted by Tcoat

If I read yours right you do that to warm up the passenger compartment not the engine anyway. It is the difference between warming up the car and warming up the drive train.

Your right its mainly to get the heater to start working sooner. I do find that my oil temps are close to 100F when I start to drive though so thats better then it being really cold right

[Tcoat]

Originally Posted by go_a_way1

Your right its mainly to get the heater to start working sooner. I do find that my oil temps are close to 100F when I start to drive though so thats better then it being really cold right

Every little bit helps.