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Discussion Starter · #1 ·
I am driving home from lunch today and some jerk in a Duracrap is tailgating me while I am getting on the highway. I put the go pedal down and nothing. Boost goes to MAYBE 5 pounds and truck can't get out of his own way. So, back it off, slow down a little more and give it fuel, nothing. Now the boost gauge is at zero. Come up to a stop light and go to take off, nothing. Zero boost, feels like my 1985 Subaru. Pull into shopping center, shut off, go in to get a sandwhich. Come out in less than 5 minutes, take off and the boost shoots up to 20+ and the back end feels loose. Power is back. Truck sounded like it was knocking when there was no boost (but hard to hear at driving speed because it is so quiet) and no turbo noise. Was idling fine when I shut it down. No lights came on. Dealer says Regen shouldn't cause anything close to this. What the heck is going on?
 

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Discussion Starter · #3 · (Edited)
There was issue with Urea system. But if it was in limp mode, why did it go back after it was shut off and why no code? I don't know what is typical for how these things work like that.
 

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Doubt it is a bearing issue in turbo. But the cool down makes me wonder. But I would think if it locked up, it woulda stayed locked up.I can't ever hear my turbo,
 

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I just got thru boost issues on 2001 my two cents..

Even with leaking stock up-pipes my turbo would make 8-10 lbs of boost WOT ...after my IH up-pipes were replaced I replaced my wastegate actuator and tried runnign truck with wastegate linkage off = wide open wastegate ....turbo still made 10-14 lbs of boost on mid to top end ....I don't know if new strokers and turbos function identically I know they are more complex ect

Stories like this make me glad i hung on to my truck even in tough times/ high fuel prices / and my past engine and current tranny issues the 6.0's and up scare the crap out of me with the prices and then all the recalls and issues people are having ....I faced my own demons thanks to the diode and up pipes once tranny is done right I will be happy with diesel POWER again :) I have 4 payments left on the truck!
 

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Gotta love electronics! I hate little glitches like that but as long as it is good now and no dummy lights then go on with it until it starts to do it regularly enough to figure out what is wrong so they can fix it. Remember this is the first year for this engine and you are a ginny pig so gotta expect things like this.
 

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....I don't know if new strokers and turbos function identically I know they are more complex ect
No wastegate on this turbo, it uses variable vanes to control turbo speed.
 

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Discussion Starter · #8 ·
Gotta love electronics! I hate little glitches like that but as long as it is good now and no dummy lights then go on with it until it starts to do it regularly enough to figure out what is wrong so they can fix it. Remember this is the first year for this engine and you are a ginny pig so gotta expect things like this.
Totally agree, just didn't want to screw the thing up. Dealer said the same thing, if it does it again, bring it in.
 

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Hey honeydew,

That thing top center is a vacuum controlled waste gate.

The turbo on the pickup is billed as a variable nozzle-twin compressor-waste gated turbo. The CC is a variable nozzle-single compressor-non waste gated turbo.
 

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Just currious here as my 7.3 does not do regen (that I know of :icon_confused: ) and I still don't have a VIN on my truck, no less my truck to read the manual to find out what regen is/does, but from what I have read here about when it is regening you loose MPG and power. With the short duration that the regen light flashes, could it be you were in regen just as you decided to jump on it and dust that duracrap? Just a thought because I would think you might loose some boost too during regen? And possibly the regen was complete before you parked it and that was why it seemed fine when you restarted. Like I said, I don't understand regen yet so this is just my wild guess.....
 

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Thom12. No regen does not affect it. It is just dumping more fuel to get dpf hotter to burn off soot. Mine runs like a scolded dog during Regen.
 

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Discussion Starter · #12 ·
Just currious here as my 7.3 does not do regen (that I know of :icon_confused: ) and I still don't have a VIN on my truck, no less my truck to read the manual to find out what regen is/does, but from what I have read here about when it is regening you loose MPG and power. With the short duration that the regen light flashes, could it be you were in regen just as you decided to jump on it and dust that duracrap? Just a thought because I would think you might loose some boost too during regen? And possibly the regen was complete before you parked it and that was why it seemed fine when you restarted. Like I said, I don't understand regen yet so this is just my wild guess.....
I thought that too, but Ford's official stance is "possibly a mild reduction in power" but nothing like zero boost. Hasn't done it since, so I am hoping it was a one time glitch. Let me tell you, going from the 7.3 to this is a kick in the pants. You are going to love it.
 

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Hey honeydew,

That thing top center is a vacuum controlled waste gate.

The turbo on the pickup is billed as a variable nozzle-twin compressor-waste gated turbo. The CC is a variable nozzle-single compressor-non waste gated turbo.
Looks like you are correct and it has both variable vanes and a wastegate. Very cool.
 

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Hey honeydew,

That thing top center is a vacuum controlled waste gate.

The turbo on the pickup is billed as a variable nozzle-twin compressor-waste gated turbo. The CC is a variable nozzle-single compressor-non waste gated turbo.
I believe you are incorrect, I should consult the 6.7 bible first but I won't.

Due to there being only one valve connected to one bank and the EGR runs off one bank, the purpose of that valve is to produce enough back pressure to open the EGR valve under certain conditions.

The VGT handles all of the remaining exhaust with no use of a wastegate. I would strongly suspect this back pressure valve is nothing more than a common wastegate doing a different job.
 

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I am a rookie to automobile diesels – but have been following posts in this and other threads and I am trying to learn. I must say, there is a great deal of technical know-how on these threads to learn from – thanks for sharing.

I am not sure how all the sensors are arranged for the DEF levels and their interaction with limiting engine output – and was wondering if the following could be applicable.

It may be possible that the DEF experienced damage while the vehicle was in transit to the dealer. (as was the case with other owners) If there is partial blockage from that damage in the line, the exhaust may become DEF starved when the engine’s increase in power is called for. – would this limit power if a DEF flow sensor was present at the exhaust?

I apologize for my ignorance shown here – just trying to help
 

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Discussion Starter · #16 ·
That is exactly what originally happened to my truck. DEF line was crushed and when engine called for DEF, not enough got through. It threw a check engine code for DEF issues. Line was replaced and codes were cleared. This happened about a week after the DEF line was replaced, but you are spot on with your assessment of the original issue.
 

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One should take the time to check out facts before trying to act like an expert, see page 45 of the 6.7 diesel information book.

Wastegate Solenoid and Actuator The wastegate on the DualBoost
VGT is vacuum controlled through a solenoid that is controlled by the PCM.
The wastegate is only used on the DualBoost turbocharger.
The wastegate opens to relieve excessive exhaust pressure at higher
RPMs.
When the VGT cannot react quickly enough to reduce MAP pressure, the
wastegate will open to reduce EP to slow down the turbo.
 

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That is exactly what originally happened to my truck. DEF line was crushed and when engine called for DEF, not enough got through. It threw a check engine code for DEF issues. Line was replaced and codes were cleared. This happened about a week after the DEF line was replaced, but you are spot on with your assessment of the original issue.

I may well be wrong but my understanding was that once the engine went into a DEF-inspired limp mode, it stayed that way until the issue was resolved (adding DEF to the tank, etc), and could only go down the power curve (less and less power, until the engine only idles).
 

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Discussion Starter · #19 ·
Dealer thought that it might have still been getting some fluid, just not enough. Or the line continued to degrade. I have no idea what the ramifications are for that on the limp mode. It also could have had ice in it as I was driving through cold conditions and the heating coil around the line was broken when the line was crushed. There appeared to be some drop off in power when the light was on, but nothing like the zero boost that I had a week later.
 

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I believe you are incorrect, I should consult the 6.7 bible first but I won't.

Due to there being only one valve connected to one bank and the EGR runs off one bank, the purpose of that valve is to produce enough back pressure to open the EGR valve under certain conditions.

The VGT handles all of the remaining exhaust with no use of a wastegate. I would strongly suspect this back pressure valve is nothing more than a common wastegate doing a different job.
Wastegate has absolutely nothing to do with egr operation...it acts just as any other wastegate...to slow the compressor wheel to limit boost.
 
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