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Discussion Starter · #1 ·
For the record, this was the cause of my Fault Code 84 (limp mode), P0101 (Mass Air Flow) and Check Engine light....:angry::eek:hmy::shocked:

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Holy over boost batman!

You gotta find out whats hanging up the blow off.
I've heard of this….never seen one, till today.

Looking forward to the rest of the story.

Rob
 

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Holy over boost batman!

You gotta find out whats hanging up the blow off.
I've heard of this….never seen one, till today.

Looking forward to the rest of the story.

Rob
Hopefully, this is only an Australian intercooler/boost problem and does not affect the U.S. Cruze diesel models.
 

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Have not heard of this on any US diesels to date
 

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Discussion Starter · #5 ·
Where is the blow off on the diesel ?

Now with the new intercooler, the full throttle acceleration is awesome and it pulls hard from 1500 rpm until about 3800 rpm, then it suddenly looses boost and you can hear something like a blow off.
Boost pressure on the OBD2 App shows max boost at full throttle around 20 PSI. Sounds pretty high to me...
Is this normal ?

Interestingly, if I just gently squeeze the accelerator, it will rev cleanly (but slower of course) past the 3800 rpm mark all the way to the 4500 rpm redline before the rev limiter kicks in.
Boost pressure when accelerating like this shows around 14-16 PSI.

Not sure if I still have a problem or is this normal... I don't want to blow out the intercooler again !!

Check out the video, you can't hear the blow off but you can see the tacho needle stop at 3800 rpm before I shift into second gear.

 

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There is no "blow off" in our turbo-diesels, they use variable-vane technology to adjust the pressure, wikipedia link https://en.wikipedia.org/wiki/Variable-geometry_turbocharger

Looking at the video, something, somewhere, is opening up under pressure.

Is it a JG (Korean) or JH (Oz) Diesel? It might have been instructive if the instantaneous fuel economy had been up displayed on the DIC.

Anyway, it's a job for a mac that understands small turbo-diesel engines!
 

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Discussion Starter · #7 ·
It sure is. With no blow off on the turbo diesels, I'll have a closer look today for a boost control valve or some other mechanism on the turbo or in the charge air pipes that controls the boost.


I suspect the ECU senses the high turbo pressure then cuts off fuel and triggers a release valve somewhere...

Good idea with the instantaneous fuel economy display. I'll check that out too.

It's a JG model.
 

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Something fishy going on……your going to billow the new intercooler in short order…….I think 20 psi is way high.

The intercooler failure was a result of something else that took it well beyond design pressure.

Rob
 

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My North American Diesel with a Trifecta Tune will regularly boost to over 30 PSI. With the factory tune it would consistently push 23 PSI into the intake. It seems the 20 PSI that you are seeing is normal operation.
 

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Discussion Starter · #10 ·
I thought 20 PSI would be pretty much normal for a diesel.

Just need to figure out why and where it's releasing the pressure from and get it sorted otherwise the boost is wasted at higher rpm.

Brad, do you know if the Trifecta tuners made any adjustments to a boost control valve or anything like that when they did the tune ?
 

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The engine in the US diesel is different to the engine in the JG diesel. (Which is different to the JH diesel.)

They aren't directly comparable. Our JG has an older Opel designed and Daewoo tweaked engine.
 

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I thought 20 PSI would be pretty much normal for a diesel.

Just need to figure out why and where it's releasing the pressure from and get it sorted otherwise the boost is wasted at higher rpm.

Brad, do you know if the Trifecta tuners made any adjustments to a boost control valve or anything like that when they did the tune ?
I do not have the technical data to answer the question accurately. I do know that that before the tune my boost gage would bounce up to the low 20's during aggressive acceleration. After the tune i would regularly see 30 psi under moderate acceleration. The tune was strictly a PCM reflash, there were no mechanical changes to the boost control linkage.
 

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For the record, this was the cause of my Fault Code 84 (limp mode), P0101 (Mass Air Flow) and Check Engine light....?:eek:hmy::shocked:

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Hi.. my Euro spec Cruze 2.0 diesel just did this code 84 P0101 and engine check light.... goes into limp mode at speed and cuts power..... stop car and all lights go out including code and i get normal power back again?
Is this radiator or Oil cooler... sorry I am new to all this! had Jap stuff before and never suffered these issues.
Can you help me please? I order MAF sensor already!
Thanks in advance.

Paul
 

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Discussion Starter · #14 ·
Sounds familiar Paul. You need to have a good look at the inter-cooler for dis-formation like in the photos of mine from a few years back in this post. Also check the rubber hose on the turbo intake as they can perish and become cracked and if not properly sealed from pipe to turbo can cause the issue you have under higher revs or load.
 
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