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

   #21  

Jack@European_Parts

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I have full access to ShopKeyPro for my service manual.
I'm a former auto technician with 25yrs experience, now teaching automotive tech, so not my first rodeo.
Appreciate the suggestions, but looking for some corners to cut, avoiding IF POSSIBLE -(please Lord) motor out timing component replacement.
Having no codes relating to timing issues frustrates me going down this timing colored road...

You mean "LostKeyPro" right?

Is the ECU possibly FOD and maybe not reporting all the faults it should?

Have you read your compression gauge correctly and has it been cross checked with another?

As an instructor you should know better than to seek to take shortcuts, like not doing the aforementioned & before changing an extensive amount of all these parts.

When setting up the timing with RTFB, you can indeed create such a cheat sheet & with use of a dial indicator of piston overall depth at rock point/TDC/BDC and with protractor degree wheel of each of the cams and lobe offsets to check chain slack, base timing and key or virtual key-way or press fits, no?


Call me crazy, however, nope asshole is fine, was not work history indicating that someone was already in there and FUBAR FOD something? :rolleyes:

(oddly only the right bank was dirty, left bank was very clean??)






FOR SHAME NEGATING JPPSG ............



Mechanical tests will always indeed win!
 
   #22  

imquattro

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SlapMeyPro isn't always correct (there are documented occasions the Bentley is wrong too for that matter), very good point, and I've shared that with my students as we encounter it.

Neither ECU's reported any timing issues.

Asking for help is one of the last things I ever do. I always try to figure out a solution using the resources at hand first.

Short cuts tips are always welcomed as long as they provide useful results. There are some that are detrimental for sure.

Yes, I've encountered defective equipment in the past. Not thinking this is the case this time. My compression tester is a new MV5532 Mighty Vac Digital comp tester, has proven trustworthy in past couple uses.
My other trusted Snap-On tester does not read above 225 and gets maxed out.

Definite signs of other hands in the mix.
 
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   #24  

imquattro

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Many thoughts into this over the weekend.
High compression would result from carbonization of combustion chamber -will investigate today -but not sold on this causing the extreme misfires and undrivable nature of the engine.

Looked all weekend for the "how to" set this 4.2FSI engine TDC to check cam alignment WHILE IN THE ENGINE BAY.

There is a mark on the front balancer pulley but when aligned with mark on block, neither bank of cylinders camshafts -which have what I believe are the bolt holes for the alignment tools mentioned in RM- close to level to accept a tool. Right bank is rotated (from the front of the motor) CW too far and the left bank is WAY CW off. And I'M CERTAIN its on the compression stroke and not 180 off.

Now, before anyone says "WELL THERE'S your answer" -I need to know if that's the procedure to set this TDC motor in situ. IF so, then I'll start dropping the motor.
 
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   #26  

imquattro

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Well, doing my best to understand the TDC procedure... the front crank mark is lined up but the cams are off on both banks. Right bank is close, but the left bank is way off. They were just so off that I figured I was misunderstanding the procedure or doing it wrong or both lol.
Will finish dropping motor today.
 
   #27  

Jack@European_Parts

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   #28  

PIVOT

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If you don't feel like finishing that motor drop, i can easily get you a cam crank waveform for you to compare. I've got an 08 4.2 in today that i could quickly get a waveform from (if you have a scope).
 
   #29  

Jack@European_Parts

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If you don't feel like finishing that motor drop, i can easily get you a cam crank waveform for you to compare. I've got an 08 4.2 in today that i could quickly get a waveform from (if you have a scope).
Yeah I'm not so sure the high compression on one bank will change with this data of the scope or will help in a huge way here, huh? :rolleyes:
 
   #30  

imquattro

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Thanks PIVOT, motor and tranny assembly already out.
Jack, thanks, already the entire SSP dl'd ;)
Next: separation.....
 
   #31  

Jack@European_Parts

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Thanks PIVOT, motor and tranny assembly already out.
Jack, thanks, already the entire SSP dl'd ;)
Next: separation.....
...............YAY!

Pictures!

Vehicle Identification No.WA1BV74L78D048214
Modelaudi q7 qu. 4.2
AQ7
Date of production31.01.2008
Model year2008
Sales type4LB4EL
Engine CodeBAR
Transmission CodeJXS

Did you use brass bunches and plastic wedged/hammers for separating covers?.......NOT steel pry bars!

Did you verify all key pins on adjusters?

 
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   #34  

imquattro

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Jack your definition of cool is definitely different than mine. Students are enjoying it though.
If I had a dollar for every "LS it" comment.....
Like the Sealube suggestion... never heard of that stuff. I'll check it out.
We'll be gentle prying stuff apart...
 
   #35  

Jack@European_Parts

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Jack your definition of cool is definitely different than mine. Students are enjoying it though.
If I had a dollar for every "LS it" comment.....
Like the Sealube suggestion... never heard of that stuff. I'll check it out.
We'll be gentle prying stuff apart...

Before you pry anything get the hidden bolts on bottom of timing covers, please don't forget them okay?

Do you have all the special tools to lock everything down?
 
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imquattro

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   #37  

Jack@European_Parts

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Pivoting in another direction, so much for the scope idea huh?

Holy sludge FOD apparent in that thing, did you inspect sump pickup yet and take off adjusters to verify all pins or keyways?


 
   #38  

Larry Manton

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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
 
   #39  

Zenerdiode

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Watched that video ‘till the end. Was going so well until he squidged that sealant on like toothpaste from the tube. The whole idea is that the bead of sealant just fills the width of the channel. Well, I suppose it gets them business, as the customer will be back with an ‘unrelated issue’ of oil starvation wrecking the engine - after a snotty string of that sealant blocks an oil way later down the road.

I’m not a Master Technician, though...
 
   #40  

Jack@European_Parts

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Dr. Z. Knows.......
Sometimes things are posted to show what not to do, huh?
Seal lube or engines die, you want it on that aluminum wall, you need it on that wall?

 
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