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'06 6.0L Low RPM Turbo Boost loss.

11K views 5 replies 3 participants last post by  bismic 
#1 ·
All,
New to the thread and to Engine Monitoring systems.
Just hooked up an Insight CTS2 and started looking at numbers to try and find a clue as to my potential issue.

The rig is an 06, 2WD Super Duty Longbed with 5-speed automatic transmition (with Tow Haul mode which doesn't seem to lock like it used to / different concern). ~130k miles
I have done all recommended upgrades except the Head Bolts (Waiting for the next explosion to pay for that upgrade).
The only After market hardware is a Bullet Proof Diesel Oil Cooler system with relocated oil Filter and BPD EGT cooler (bigger water coolant tubes).
I did have a BPD Water pump put in too.

The issue.
I can't get more than 5-10psi boost until I hit 2000 RPM or so.
Very difficult to get moving from a complete stop.

I used to be able to Power Break and get 25psi on the dash mounted Boost Indicator.
I could give it 3/4 Throttle, Full Breaks, Not Moving and spool up the turbo to at least 25psi.
When towing a trailer, it's useful for crossing highways to be full power before letting off the break.

I'm on my 4th Turbo. Maybe I'm hard on turbo's, but I doubt it.
The factory turbo shredded and launched metal parts into the exhaust system (23k miles). Ford said it was "known issue"
The Second turbo worked well until about 65k miles when the VGT would get stock closed (Over Boosting).
The Third turbo had the this problem (low boost) so ford replaced it with my now fourth turbo.
Ford replaced the Piston thingy, after putting the 4th turbo didn't fix the problem.
still have the problem.

Now I have my CTS2 Insight and am looking for what to check and look for.
I have been reading your threads, and checking my numbers, but decided to just ask you guys your thoughts.

Mass Air Flow maxes out around 340 under full load and full throttle. Normal or possible intake restriction?
Exhaust Back Pressure is 2psi to 15psi (Idle to Max Power). Possible Exhaust leaks or restrictions?
Variable Geometric Turbo duty cycle is 65-70% at Idle when warmed up (180f Coolant and Oil temp).
VGT duty Cycle is around 20% at full load, full power
Note: It is rare for me to see 28 pounds of boost these days, unless I'm towing up-hill with a 30 minute warm up.
Manifold Air Pressure appears to match my factory boost Gauge (+15psi or so for Sea Level pressure).
Engine Load is 25% at Idle in neutral (no A/C, No Fans, No Stereo).
Engine Load is 35% when in Drive, stopped, Idle (WITH A/C, Fans, Stereo on)
Engine load goes to 100% Real Easy, like way before I hit 15psi on the Boost Gauge.
I do not have the Exhaust Gas Temp sensor installed so I don't know what's going on there.

Not sure if any of these are indicators, or if they are even within tolerance.

Any advice on what to look for next, would be helpful.

Thanks,
 
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#3 ·
(with Tow Haul mode which doesn't seem to lock like it used to / different concern)

I can tell you that IF you have a transmission issue, that the PCM will do its best to not further the damage and hold back the boost, you may not have an illuminated check engine light, but there could be codes stored for a transmission issue
 
#4 ·
Thanks for the response.

I have not had an Engine Tool Light come on, or any alarms.
I pulled a P0500 from the CTS2.
"Forums" say it's a speed sensor.
<<<snip>>>
P0500 - Vehicle Speed Sensor ADescription: Indicates the powertrain control module (PCM) detected an error in the vehicle speed
information.
Possible Causes: • Open in the VSS harness circuit
• Short to GND in the VSS harness circuit
• Short to PWR in the VSS harness circuit
• Damaged wheel speed sensors
• Damaged wheel speed sensor harness circuits
• Damaged ABS module
• Damaged PCM
Diagnostic Aids: Monitor the VSS PID while driving the vehicle. This DTC is set when the PCM detects a
sudden loss of vehicle speed signal over a period of time. If vehicle speed data is lost, check
the source of the vehicle speed input.
<<<End of Snip>>>

Speedometer is accurate, not sure if this is a real code or not.
I'll clear it and see if the code comes back up.

Thanks again for the response.
I set an appointment and will have my Transmission checked.
Sometimes it feels like it won't lock into gear at 55mph. RPM's go from 1200 to 2200 based on throttle position. I'm pretty sure it's suposed to be locked in to 4th at 55, 5th kicks in at 60-62mph (With Tow Haul enabled, of course).

Back to the Original Low RMP, low Boost Issue.
I noticed today, after starting the engine (80 degree EOT), VGT is 85% Once I touch the Brake Pedal for the first time (waited for 120Degrees), it drops to 65% or so and never reach's 85% again.
So it's capable of 85%, but chooses not to close down that much.
 
#5 ·
Got the Diagnosis from Ford today on the Low Boost at Low RPM issue.

VCT Actuator is not responding properly.
Only reads 1.4 Ohms instead of 2.x Ohms.
The Part is still under warranty from the last time it was replaced (11 months and 15 days ago).

When I took it in, I also let them know the engine was missing when I tried to hold 2000 RPM.
That came back as 4 "Weak" Injectors (#3,4,6,8) and $2600.

I'm hearing that Injector failure in inevitable.
Would an after market Fuel Recirculation system help increase the life of the Injectors?

I'm also reading that long periods of Idling is not good (as with life).
Messes up the EGT valves and builds up soot.
I guess the Diesel engines of my Fathers age are a completely different animal.

Time to re-think how I use the motor.
Maybe after all this is done, I'll get a little better than 9mpg?
 
#6 ·
You might have low fuel pressure (several ways to solve it if you do - not just immediately going aftermarket). You really should measure the fuel pressure.
 
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