16618 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)

**paul b** · 24-12-2008,06:18 PM

I think I've sorted it...

The air inlet pipe connecting to the EGR valve had come away (not on the EGR side) and was leaking air out of the connection. The metal lugs on both sides were worn, so the pipe keeps coming away, and for the first time it came away completely today... and with a horrendous noise!

Its really weird considering, that right next to where the pipe connects, is some sort of sensor. I'm surprised as to why that didn't have some odd readings.

There was no fault codes at all left on VAG-COM, after fitting the turbo the van thought it was fine again.

However, I'm now thinking I had two failiures, as when I first lost power, flicking the ignition on/off bought back the boost. Then after putting up with it for a while I lost the boost for good, and the turbo must have only ever been working at say 25%.

Maybe the overboost increased the wear on the lugs on this connector?

The turbo I took off was filthy, but there wasn't any play in it whatsoever, although it did feel a bit tight in places. I'll certainly keep hold of it, give it a good clean, as it may just be a bit coked up. Definitely not like the turbo I took out of the Skoda, that was definitely due for the dustbin!

I'll get to VW when they are back in following Christmas. I'll update here when I've fitted the new pipe.

Many thanks for your help Paul!

Paul

Originally Posted by elPaulio

Hi Paul,

Yeah, mines is still running hunky dorey!! Not checked for any codes lately, but still pulling well.
Have you checked that you've not damaged any vacuum hoses when re-installing the turbo? No boost sounds like it could be something really silly!!
I can't see the EGR cooler affecting it, my coolant loss was down to a faulty water pump not the EGR cooler at the end of that day. Still not sure why they replaced that!!
I would definatly step back and then check every single wire, hose connector around the turbo side and see if you can see anything that looks untoward.

Are you getting any codes at all??

Can you hear the turbo spooling up? I keep thinking this has to be a piping issue as the turbo should spool if the wastegate isn't open, and if the wastegate is open then you've got some sort of vacuum issue. I think!!

Let me know how you get on buddy!!

Paul

**elPaulio** · 27-12-2008,10:16 PM

Woohoo!!

A good ol' christmas present to yourself there!!

I'll keep my fingers crossed that was the problem!

Let us know bud, and as always, your welcome

Paul

**cavalier740** · 29-12-2008,06:31 PM

My mate has a garage/mot place and he's got the contract for the local taxi company who use Skoda Octavia Diesels. He changed 2 of my vaccuum hoses because they had worn holes in them and guess what?? My Bora diesel has never run better!! I was amazed at how well it pulled. He has a reel of the hose on the wall and changes the vaccuum hoses every time a taxi comes in with overboost problems. I was quoted £650 for a recon turbo and all he charged me was £5 for a length of hose.

**martin1810** · 30-12-2008,07:22 PM

I know it's a bit late to say this but turbo faults often turn out to be damaged pipes or leaks where pipes connect. A simple vacuum test will often find the leaks but most garages just rely on computer fault finding. It's often worth getting someone to gently rev the engine whilst you pull and push the vacuum pipes. If by luck you hit the right spot you will hear the engine note change.

**paul b** · 30-12-2008,11:39 PM

Originally Posted by martin1810

If by luck you hit the right spot you will hear the engine note change.

You certainly will. On my first checks, I couldn't see or feel any loose connections at all. It was a costly miss, I'm 500-and-a-bit-quid down now.

Paul

**cavalier740** · 31-12-2008,02:17 PM

Its probably worth investing in a length of hose and changing them before anything else. Its the kind of job a DIY Tech can do.

**paul b** · 01-01-2009,10:29 PM

Originally Posted by cavalier740

Its probably worth investing in a length of hose and changing them before anything else. Its the kind of job a DIY Tech can do.

Haha! I'm a an ex qualified Toyota mechanic and still missed it... I'll definitely be into VW soon for a new pipe.

Paul

**martin1810** · 05-01-2009,05:38 PM

Paul do you remember the last of the carb fitted cars, covered in little vacuum pipes. Thats what started me looking at diesel vacuum pipes closely. The pipes would often perish or work loose and make a car run rough.

**paul b** · 05-01-2009,05:45 PM

Originally Posted by martin1810

Paul do you remember the last of the carb fitted cars, covered in little vacuum pipes. Thats what started me looking at diesel vacuum pipes closely. The pipes would often perish or work loose and make a car run rough.

Indeed I do. Worked on many, many carb Toyotas.

It is amazing how bad they run when this pipe has fallen off, it leads to a sensor, only there wasn't any problems with a sensor according to VAG-COM, so I didn't really think of it as a problem.

After the experience with the Octavia, I got drawn in to needlessly replacing another turbo.

EDIT: And by the way the new pipe is fitted now, at a cost of nearly £50 from VW! At least the van runs perfectly now.

Paul

**elPaulio** · 28-08-2009,01:04 PM

Hi Paul,

I know this post is a long time gone, but one of my mates at work is now getting the same code on his A3 2.0 140 TDI and I was wondering if you could give me a bit more info on which hose you replaced so I can have a look at his?

Any pics would be ideal, but a description will be fine too

Cheers in advance

Paul