08 4.2FSI Q7 Multiple cyl misfire. ROUGH running/ barely idles -at wits end....

   #41  

Larry Manton

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Noted in a Toyota specific class, highly specific on how you apply the sealant on front timing cover, and do it wrong and it is hosed.

As Jack says Read the Fine print, not fun but Important.
 
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   #42  

PIVOT

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waveforms > engine R+R. Call me lazy, i'd rather take a few minutes to grab a waveform before i remove an engine.
 
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Larry Manton

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Pivot, that is just stupid.

LARIMORE
 
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Jack@European_Parts

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Jack, I know the VAG is some kind of sweet tool. And I know that is what this forum is about not scopes.

And also I know a guy like you and the team from Ross tech can probably tell what is wrong before opening the hood, I call this empirical studies, experience, just is what it is.

But with an engine as complex as this, would have done a relative compression and compression wave form back about page one before buying a butt load of parts. As. You note all the lines might look sweet but what if a keyway or other is compromised now what do we trust.

As you stated with no codes has somebody played with it?., I hate it, makes it really tough for the garage guy when trying to trust the scanner data.

Again great stuff, have a great new year.

LARIMORE
Scopes and scanners like all tools are great and have a place. In today's day in age and the incestuous pervasive FOD are warranting the original approach to diagnostics.

It's called basic mechanical/electronic tests!

Think about it here, the industry as a whole has lost their way. We have an instructor & who doesn't follow them either. I sure hope he is teaching them or will consider the reinforcement of that procedure for his pupils now!
 
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Jack@European_Parts

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waveforms > engine R+R. Call me lazy, i'd rather take a few minutes to grab a waveform before i remove an engine
Must be a ton of damaged induced harness's in your shop area huh?
So you would rather run an engine knowing it is in full on misfire and do potential damage, from fuel contamination etc. versus do an actual compression check and get a real analysis of the situation?

Better Pivot and rethink your over complex process huh?
Here is a KISS! Yes indeed you are lazy!
 
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imquattro

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I believe the left bank's exhaust cam had skipped some teeth. We heard some additional clicks as we were turning the motor (CW) over to access torque converter bolts. We were using the front pulley to turn the motor over.
Came to a hard stop just shy of the final two bolts.
Found #6 cylinder's exhaust cam trying to open valves while piston was coming up.
Had to remove cam adjuster with cam rolled back in safe position to allow motor to turn over to access final TC bolts.
Will check cyl #6.
Removed tranny
Removed cover and here we are.
Tools still haven't arrived for timing service (expected today). Good time to clean up and take notes.

https://drive.google.com/open?id=0B235pkx1LKL8N1hsdG5KYWJJYllpZWVXZDlLaHliOVhHR1Jv

https://drive.google.com/open?id=0B235pkx1LKL8QUpwMnZvU0s0ZHFoSFVVaWtNSVNUbl9vYUtV
 
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imquattro

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What is the procedure to check the cam sprocket adjusters.
They don't appear keyed to camshaft's
additionally, I've watched this in regards to a similar design but in contacting the company, they stated the Q7's 4.2FSI motor doesn't use this system.

Timing componenets ordered....

**Sump is in process of being checked**
 
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Jack@European_Parts

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   #52  

Jack@European_Parts

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Yes, I noted that guide was missing a piece when I pulled the left upper cover. I removed it entirely before it dropped any more.

Am I referencing a chain guide here, I think not?

Did you see the possible pins that can break "inside" the adjusters themselves to permit a hydraulic freewheel and rely on nothing but oil PSI to hold a base/max position being negated?
 
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imquattro

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Am I referencing a chain guide here, I think not?
Thought you were...

Did you see the possible pins that can break "inside" the adjusters themselves to permit a hydraulic freewheel and rely on nothing but oil PSI to hold a base/max position being negated?
Simple answer. no, I don't think so. I honestly don't understand what you're referring to. Are you talking about the "pins" that were referenced in that video link I posted earlier or something else? I don't currently have a penta-star socket (seems different than a Torx) to disassemble the cam adjuster -if THAT is where this pin is you're referring to.
 
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PIVOT

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Take a look at the JHM motorsport video about the old adjusters, it'll give you a good visualization of the aforementioned pins
 
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Zenerdiode

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Sometimes things are posted to show what not to do, huh?
Definitely. :)

We heard some additional clicks as we were turning the motor (CW) over...
Eeergh... :eek:

Found #6 cylinder's exhaust cam trying to open valves while piston was coming up.
I’m cringing. But it’s great to find the root cause.

I had a turbo let go on a 1.8T years ago. It first sounded like a screeching bird when trying to boost. So in my diagnosis, I pulled the inlet hose to the turbo; and the compressor impeller looked intact and spun freely. I nearly started looking elsewhere, but something in my gut told me it’s definitely the turbo - and just get the thing off for a proper look.

Well, turbo had sheared it’s shaft; and the turbine was free to move in an x, y and z axis. :facepalm: The oil feed pipe on those 1.8Ts ran round the rear of the engine then under a heat shield above the exhaust manifold. The oil was so caked in that pipe I couldn’t budge it with 100 bar hydraulic pressure from our test rig.

Feels satisfying when you’re done and it’s ticking over smoothly as you’re tidying up and doing your final check for leaks.
 
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Jack@European_Parts

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The oil was so caked in that pipe I couldn’t budge it with 100 bar hydraulic pressure from our test rig.
Again why I think all turbo cars should have a bifurcated sump, pump and after cooler to operate when shut down with water circulation.

Engines would be far better off!
 
   #60  

imquattro

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Because there is a complete vacuum of information on these newer camshaft adjusters to support NOT taking them apart to check their operation and literally found NO pictures of the insides, I disassembled mine to investigate/clean.
Looks like Audi fixed their earlier cam adjuster style issues -note the hardened ring for the pin to lock into.
https://drive.google.com/open?id=0B235pkx1LKL8aXREaUxYYjRJOHdFR01QUlZ4YXM1OFF6Qlo0

https://drive.google.com/open?id=0B235pkx1LKL8a3lIdGFCRkVFQnYtRENjdFpvNW55dmpIeHpv

https://drive.google.com/open?id=0B235pkx1LKL8d1N6Sy1RRzhCWTcxcjViV1hQX0k0NVlVd29n

Now we all know why there's nothing notable mentioned about them.
---no news is sometimes good news---
 
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