Alright folks, let's see if you can figure this one out.

About the truck...
6.0l w/ 190K miles
bulletproof EGR and oil cooler, ARP studs, PowerMax turbo, Banks exhaust, Edge tuner (currently running towing tune but have same issue with no tune.

I'm pulling a 9K trailer from AZ to MO. Started out getting 13.5 MPG and that is usually what I get when pulling, usually get 17.5 with no trailer. Half way through the trip my MPG went down to 7.5 and EGTs would climb over 1400 pretty consistently (normal EGTs for this load would be 1200). I understand that the high EGTs correspond with the fuel mileage. Other than the fuel/EGT issue, the truck isn't pulling as well as normal and I've experienced about 3 events of sudden severe loss of power but the truck will quickly get back on it, acts like a loss of fuel pressure.

Boost and EBP seems normal, boost has no problem with 25-30 lbs and EBP is a little less than double boost, which I'm thinking is normal so I have eliminated the turbo as an issue.

I replace the fuel filter every 10K mi along with oil (rotella T6).

Coolant and oil temps are ok over heavy load (ECT reading between 205-225, EOT reading between 205-230).

The truck appears to be blowing healthy black smoke.

Other than poor MPG/high EGTs and sudden loss of power, the engine runs fine. I'm at a loss, please help.

 

Assuming you are confident of the turbo, boost, EBP, MAP, etc (We would prefer numbers though)...
First check for codes
Second, check for something dragging (brake, belt pulley, tensioner, A/C compressor, etc).
Third, check tire pressure
Fourth, check fuel pressure if you suspect it being an issue

 

With boost at 16, EBP was at 24 and MAP at 29. There was never a code, I checked like a mad man because that would be a start at least. Not seeing anything out of place underneath.

 

Tire pressure is spot on. The Edge tuner doesn't have a fuel pressure gauge but it does have an injector pressure, that reads 2500-3000

 

After you check the items Bismic listed, how bad were the winds? A good head wind can destroy your mpg's.

 

I don't believe wind is a factor because these numbers have been constant. I've had to fuel up every 200 miles for the last 800 miles and I have a stock 26 gal tank. I'd understand if it happened once while we were driving on a windy day.

 

Wind is a killer for sure, but I would think that you would have realized/accounted for it as well.

The EBP number looks off to me.

What are EBP, MAP, and Baro at KOEO?

 

Thanks for the quick replies.

KOEO numbers...
MAP 14psi
Baro 14.3
EBP 0

 

Your monitoring system is probably reporting EBP in "gauge" pressure. IMO you should set it to absolute pressure. By setting it to absolute pressure, you can verify it is the same as MAP and Baro at KOEO.

 

Just some numbers to play with if you want:

RPM............3300.......3000.......2800........2 600........2400
VGTDC#...32-42%...35-45%...36-46%...38-48%....40-50%

VGT % duty cycle:
low idle......73%
high idle.....43%
cruise........55%
light accel ..67%
hard accel ..38%
coast.........57%

• EBP_DES should be 25-35 psi from 3300 to 2400 RPM under full load.
• EBP_G should be within 2 PSI of the EBP_DES.
• MGP should be 22-27 psi from 3300 to 2400 RPM under full load.

No-Load Boost Pressure Test
RPM..........VGTDC#............EBP_G............MG P
Idle...........60-82%............0-6 psi..........0-1 psi
WOT..........30-45%...........4-18 psi........2-9 psi

 

Following: I'm having the same issues but it seems that it is a over boost at lower rpms. I disco's the ebp and it leveled out a little but I had a spare and it returned. This has been on going since I have done the STC fitting and the delete. Maybe a turbo relearn would help.

 

• High fuel usage
• High EGT
• Good Boost
• Poor power
• Black smoke

SWAG - fuel injector pushing excessive fuel

I'd be doing a contribution test.

 

I agree Jack. Unfortunately most of us have to pay money for that! AND - I hate taking my truck into the dealership. Several around here are not trustworthy IMO. Last thing I would want is to have the PCM flashed!

 

Just some numbers to play with if you want:

RPM............3300.......3000.......2800........2 600........2400
VGTDC#...32-42%...35-45%...36-46%...38-48%....40-50%

VGT % duty cycle:
low idle......73%
high idle.....43%
cruise........55%
light accel ..67%
hard accel ..38%
coast.........57%

• EBP_DES should be 25-35 psi from 3300 to 2400 RPM under full load.
• EBP_G should be within 2 PSI of the EBP_DES.
• MGP should be 22-27 psi from 3300 to 2400 RPM under full load.

No-Load Boost Pressure Test
RPM..........VGTDC#............EBP_G............MG P
Idle...........60-82%............0-6 psi..........0-1 psi
WOT..........30-45%...........4-18 psi........2-9 psi

bismic, so I ran a no-load boost pressure test and everything appears to match up with your above numbers. Something came to light though... called bulletproof and explained the issues. The tech asked me if I was running a PowerMax turbo which I am, he said that's the issue. Bulletproof quit selling the powermax about 3 years back due to similar issues that came about while towing. That's a bummer since this turbo is only about two months old. The turbo works great and adds a ton of juice when around town but isn't sufficient when pulling.

 

Interesting. Thanks for posting.