Engine Start in Higher altitudes

[MUgolf2008]

I have a 2015 Ram (only 42k miles) and seems that when it sits for a couple days without being ran, it doesn’t start up super smooth. When we go to higher altitudes (Northern Arizona) to camp and it sits for a day, the next day it really struggles to start… almost doesn’t start.

Anyone know what would cause this? Hard to recreate at a repair shop to show them and been happening for a long time now…

Thanks!

 

[Burla]

Your truck adapts to environment, adds more air when needed and adjusts fuel air ratio. It should normalize within day or two. As for sitting in normal conditions, it should start. Battery and air cleaner I'd check first, 2015 if it is original battery, I'd get it checked for cold crank amps or whatever they check for at a tire shop.

Think about it, you need o2 and fuel to have combustion in your engine, but if you are in low o2 environment, the truck has to adjust or it dont work. It takes a little while for sensors to figure it out. How close to the mountain is your house, do you drive for hours on your elevation before getting home?

 

[Burla]

You always use 89 octane?

 

[kurek]

I have a 2015 5.7 that I bought new in Flagstaff and lived in Phoenix until the end of 2019, visited Flagstaff, Utah, Colorado, etc regularly and never had difficulty with starting at altitude, summer or winter.

Sorry that isn't much help I only wanted to illustrate that it's not a necessary characteristic of the engine so you're right to look for a fix.

 

[Benji85225]

Your truck adapts to environment, adds more air when needed and adjusts fuel air ratio. It should normalize within day or two. As for sitting in normal conditions, it should start. Battery and air cleaner I'd check first, 2015 if it is original battery, I'd get it checked for cold crank amps or whatever they check for at a tire shop.

Think about it, you need o2 and fuel to have combustion in your engine, but if you are in low o2 environment, the truck has to adjust or it dont work. It takes a little while for sensors to figure it out. How close to the mountain is your house, do you drive for hours on your elevation before getting home?

Mine just did the same thing in Williams (7000 ft) both mornings we we were there - after hitting the start button the engine back fired twice, had a 1 second pause , then proceeded to fire up like it had a very heavy cam with a fuel shortage for 6-8 seconds , then went to 1400 rpms and hung there for 40-45 seconds before slowly descending to normal idle . It would start up normally for the rest of the day , then happens again the second morning. It was crazy - at first I thought it dropped a valve/broke a valve spring due to the sound , but sounded normal once it calmed down and we started driving. It does have a AfE magnum Force stage 2 cold air and borla atak cat back exhaust . No other mods. Engine was replaced due to lifter failure/hemi tick 7k miles ago .

 

[Bigskyroadglide]

I was just at the canyon, in my 2024 warlock 5.7 hemi. No issues starting. I'd follow @Burla advice. Air fuel spark

 

[Burla]

Mine just did the same thing in Williams (7000 ft) both mornings we we were there - after hitting the start button the engine back fired twice, had a 1 second pause , then proceeded to fire up like it had a very heavy cam with a fuel shortage for 6-8 seconds , then went to 1400 rpms and hung there for 40-45 seconds before slowly descending to normal idle . It would start up normally for the rest of the day , then happens again the second morning. It was crazy - at first I thought it dropped a valve/broke a valve spring due to the sound , but sounded normal once it calmed down and we started driving. It does have a AfE magnum Force stage 2 cold air and borla atak cat back exhaust . No other mods. Engine was replaced due to lifter failure/hemi tick 7k miles ago .

That needs to be addressed, from this seat that sounds like perhaps a slow fuel issue where too much fuel is slowly getting in cylinder, but only due to overnight leaking, so slow, because the rest of day it is ok. It doesn't sound like timing or even air, this sounds like fuel is my first thought. Did you run codes?

 

[Burla]

Open throttle, press gas pedal to the floor before start, hold the pedal to the floor, then crank engine shouldn't start. Then try starting it like normal. Look up clear flood mode.