Low boost/power at altitude - Diesel Forum

SuperDutyDoug · 08-17-2006, 10:21 PM

Hello all,

I've encountered a problem with my '03 PSD. I am running the original flash from May '03, and the truck runs fine at sea level. I have just returned from an Oregon vacation, and had a problem climbing a grade near Klamath Falls. Here are the particulars:

~6% grade @ 5000 ft.
No trailer or payload to speak of.
85 degree day.
engine is stock, except for a 4" cat back.

I had a tough time maintaing 60 mph up this grade! My foot was nearly to the floor, but all I could muster was 15 lb of boost. The EGT was about 900 degrees, with no black smoke out the tailpipe. Even with about 2600 rpm, the engine was flat.

I checked the air filter - no problem there, as it was clean and recently changed. Also, I cleaned the EGR valve about a month ago. Fuel filters recently changed. Mileage on the truck is 50K. The next day, I ran the truck at about the same elevation and the problem was gone. Accelerate up the freeway onramp, hammer down, no problem reaching 25 lbs of boost.

What might account for this? Could it be turbo vanes sticking? I know I don't run the truck as hard as I should. I seldom haul with it, so the only thing I can do is periodically stand on it.

I have made an appointment to have it checked at Ford next Tuesday. I really don't want it reflashed unless there is no other way to get it running right. But I sure don't want it laying down on me like it did the other day. Thanks in advance for any ideas or reports of similar problems.

Doug

FamilyRide · 08-17-2006, 11:21 PM

Altitude =less dense air = less oxygen.

Boost will be less unless the ECM can accound for the change.

But, I don't ever recall having that issue, but the times I've been at 5000-11000 feet it was cold which = denser air. [img]/ubbthreads/images/graemlins/shrug.gif[/img]

Skweeker · 08-18-2006, 08:40 AM

Exhaust Back Pressure sensor??

drwoodchopper · 08-18-2006, 12:17 PM

I am sure the altitude was a coincidence. It is probably one of the problems suggested stuck vanes or ebp sensor not likly egr either. I live at a higher altitude than that and can still esily hit over 25lb of boost over 8000ft.

SuperDutyDoug · 08-23-2006, 11:37 AM

Hello all,

Thanks for your inputs regarding the problem I posted last week. Yesterday I took the truck into Ford for a diagnosis. They found no trouble codes stored, and the turbo boost checked out OK @ 27 lbs stock. After much debating, I allowed them to reflash it. They did the 06E17 flash, and another one that preceded it (can't remember the designation). Well, it hasn't been very long since the reflash, but so far so good. The PI is gone, but I don't care about that. I like the clatter at idle. Tow/haul is a bit less harsh, but still works OK for me (previously it would sometimes slam the 2-1 downshift very hard). Power seems the same, but I can't comment on fuel mileage yet. The truck is bone stock, except for a 4" catback. I have heard that folks get better a outcome with stock trucks versus ones with more extensive intake/exhaust mods.

One thing the truck had also been doing was rough idle + smoke on startup. This is gone - so far. Thanks again for your responses.

Doug

Rich807 · 08-23-2006, 02:27 PM

[ QUOTE ]

They did the 06E17 flash, and another one that preceded it (can't remember the designation).

[/ QUOTE ]

I thought I've read from some technicians posting that flashes are not cumulative i.e. they don't "stack" on top of each other? In other words when a flash is done it is an up to date package that replaces all previous information.

Just curious.

DieselDocFX4 · 08-23-2006, 02:33 PM

Changing altitude all the time or ever so often your truck gets custom to the altitude that it is drivin at and then it take a couple of days or maybe a week to get use to different altitudes. My brother and I have the same trucks 06's he lives in Florida I live in Wy he came to visit and pulles a trail only wieghing about 3k and couldn't hold 70 mph on flat ground. I was pulling a 25ft toy hauler and could keep climbing up the speedo. He was mad and wanted to get ride of the truck. After being in Wy for a week his truck was running like a grape ape and could smoke me pulling the same setup. [img]/ubbthreads/images/graemlins/smokin.gif[/img]

blakerj10 · 08-23-2006, 05:31 PM

Mine recently started the same problem. I live in Laramie, WY at about 7500 feet. I can only get 15 psi of boost in my 05. I used to be able to hit 28 all the time. I brought it to the dealer, and they say everything looks fine. Anyway I can check the EBP or turbo vanes myself. I hate trying to convince the dealer that something is wrong.

dvtech · 08-23-2006, 08:04 PM

[img]/ubbthreads/images/graemlins/wink.gif[/img]if some of you guys are encountering turbo veins sticking only at high altitudes then you definately have other concerns. if the veins are sticking then they are going to stick at any level regardless. i would recommend all to when taken into your dealer, insist they pull the iat2 sensor & clean it. this is a big overlook from alot of dealers. this sensor will hardly ever set a code but on rare instances. i've had customers come in that were traveling & said they were having this problem & it was from a underboost. leaking cac hose or separated cooler radiator. most of them had this sensor plugged up & they would email me back & said it fixed there power problem. but it was egr related. not turbo related. [img]/ubbthreads/images/graemlins/smokin.gif[/img]