Tow power / boost issue
2013 CCLB, 33,500 miles, stock emissions
While towing a 9000 pound trailer at interstate speeds (75 to 80 in Wyoming), when pulling a hill, the truck downshifts to 4th gear, boost is about 18psi, eng and transmission temps in the 230F range, EGTs around 500C or 935F. RPM increases normally to 3000 then the turbo gets very loud and boost drops to about 10psi. The truck shifts to 5th gear, noise decreases but is still present, shifts to 6th and noise goes to normal after a couple seconds and boost builds normally.
This just started today. I have about 8000 miles towing this trailer and never had this before.
Ideas? I have about 350 miles until I'm home so I'm headed back out. Will play around with manual mode and see what it does.
I also took a video of the gauges while this happens. Audio is difficult to discern. I will try to get better audio and post when I get home.
Thanks,
Bob
80 mph uphill is pretty harsh
The loud noise is not your turbo - it is probably your coolant fan coming on full blast
Your boost drops because your oil is hot and the engine temporarily derates to save itself
I am assuming your truck is probably chipped?
(On edit - if the maximum boost your truck can make is 18 lbs you have a turbo problem or a loose connection to your charge air cooler)
a 2011 truck won't boost over 20psi. The 2015+ will max out at about 24.
It's possible you have a turbo struggling but may have to wait until it gets worse.
Personally, I think you should put the trans in 5th gear, climb the grade, and just accept that you can't have 80+ mph. Don't forget, you're rolling at almost 20k combined.
80 mph uphill is pretty harsh
The loud noise is not your turbo - it is probably your coolant fan coming on full blast
Your boost drops because your oil is hot and the engine temporarily derates to save itself
I am assuming your truck is probably chipped?
(On edit - if the maximum boost your truck can make is 18 lbs you have a turbo problem or a loose connection to your charge air cooler)
Boost should not drop off even when engine oil temp maxes out at 246F. The system pulls fuel to cool not boost. Boost (air flow) cools the pistons.
OP I suggest you data log with ODB/Torque app or equivalent. You can later evaluate fan rpm, temps, ect at the time when boost drops off.
The trailer is 11 feet tall so yes, there is a lot of wind resistance.
Yes I was running her hard. Had been running 75+ all day but the oil temps, coolant temp, etc were all good. I do need to record more data from TorquePro. Need to look at what I did capture.
The truck is all stock.
Max boost is about 19psi.
I made a short run without the trailer and the turbo worked fine producing max boost up to nearly 4000 rpm with the transmission in manual to force the rpm to climb. I won't be traveling again for a while and don't have any large hills with a high enough speed limit nearby to do any testing.
My guess is that the turbo is trying to die. Don't want it to go while I'm on the road but since there are no codes and I don't have the terrain that will allow me to duplicate for the local dealer, I guess I'm stuck waiting for it to die.










