[Vwdiesel] Limp Mode Frustration

[Dave Cook]

I did clean the manifold, and it didn't have a very thick layer anyway.  


I can reach down and move the actuator rod, and when I had the head off I also checked and it seemed to move appropriately then too.  I do intend to set it side by side to my Golf and see if they feel similar.  But it does move, and I can attest that no one has tried adjusting anything since before when it drove well.

 
Dave Cook


________________________________
 From: "dieseltdi at verizon.net" <dieseltdi at verizon.net>
To: Dave Cook <davevw at yahoo.com> 
Cc: vw fans <vwdiesel at vwfans.com> 
Sent: Saturday, March 3, 2012 10:04 PM
Subject: Re: [Vwdiesel] Limp Mode Frustration
 
Just off the top of my head, it sounds like the VNT vanes are stuck causing an over pressure situation.  If the vanes are stuck they can't modulate the boost pressure.  Another possibility could be a really clogged intake manifold.  When you fixed the other stuff, did you remove and clean the intake?  I also had this problem when I installed the hoses on the N75 wrong.  You might want to closely look at that also.  Just a few things off the top of my head.  I will kick it around a bit more and think about it to see if anything else comes to mind.  Hayden

On Mar 3, 2012, at 9:43 PM, Dave Cook wrote:

> This is a friend's '01 Jetta TDI.  Keeps going into limp mode, sometimes with a check engine light, sometimes without.  Has been this way for a 
> long time.
> 
> Last spring, I replaced all the vacuum lines while replacing the head 
> gasket, timing belt, and a few other bits in hopes of fixing this.  Also
> replaced the N75 at that time.
> 
> Still goes in limp, and does it more often than not at this point.
> 
> I decided to try some more troubleshooting today.  In doing some 
> driving, I found that the ECU would show two different codes after going
> "limp".
> 
> They were:
> 
> 16618 - Boost Pressure Regulation 
>             P0234 -
> 35-00 - Limit Exceeded (Overboost Condition)
> 16492 - Manifold / Barometric Pressure Sensor (G71) / (F96) 
>             P0108 -
> 35-00 - Signal too High
> 
> They were showing up sort of alternatively, maybe a couple times one of 
> them and a couple times the other.  Or a couple one, then the other, 
> then back to the one.
> 
> Once, both popped up at the same time.
> 
> I was romping on it going up hills during this testing.  It only took a 
> couple seconds of heavy acceleration to cause limp to come up after 
> having shut down the car and clearing the codes.  
> 
> I then pulled the MAP sensor from the intercooler.  I noted a oily 
> coating on it, so I cleaned it off with air flow sensor cleaner.  No 
> change on reinstallation.
> 
> I'm thinking the problem might be the MAP sensor, but my friend doesn't 
> want to throw money at the car hoping something fixes it.  
> 
> Any other thoughts?
>  
> Dave Cook
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