Altitude and high ambient temps occurred during my road trip last month and I noticed a lot more black smoke at the tailpipe under speed. Here's the conditions: Altitudes up to 8000' ASL, Air temps above 95F to 118F, towing approx 4500 lbs (double axle uhaul, cab hi, fully enclosed trailer, EZ set on power level 1. Route was direct, freeway and highway, speeds approx. 70 mph open road.
I traveled 3,504 miles on 224 gallons of diesel for an avg 15.64 mpg and started and finished at sea level. My truck ran flawlessly except for popping the blower motor resistor and having the a/c needing to cycle frequently, losing cooling efficiency for 10 or 15 minutes til regaining full efficiency. I only had "HI" blower speed.

Should I be concerned about the excessive black smoke, or is this normal for my conditions?

Thanks, Kurt

 

Quite normal. Density altitude was very high, so you have less air mass per volume.
I attribute the smoke to the Edge chip that allows more low boost fueling. Without the chip you would have noticed a loss of power, but no smoke.
If you expect conditions like these make absolutely sure to have a fresh air filter. Even long before the filter minder tells you to change it the amount of air can be too little under these conditions.
(We have that a lot over here with excavators and the like in the mountains in summer, filter minders calibrated to show that you choke the engine at sea level in cool temps)

 

Thanks for the reply Alpine. I run a NAPA Gold BHAF and just changed it out last Fall, my filterminder didn't really show any restriction on the old one from '07....

Truck ran great, just noticed a smoky tailpipe with that uhaul. I'm still sitting on a set of rv275's and studs, gonna rebuild my drivers seat and upgrade to Sport headlights right now and get the parking brake figured out...

Kurt

 

As someone who lives at 6700’ and routinely go 10k+ what you describe is normal. Wait until you are pulling 10-15k + pounds and you stop at a stoplight on an uphill at 9k elevation on a warm summer day. Sudden eclipse of the sun is entirely possible with an edge box and 275 injectors

 

Thanks for the replies, I only see about 4000' around here thru the passes to MT and the ski area and hadn't noticed much smoke unless I summon it!