A little help with a little/big problem...

[stevowmt]

Afternoon all. So after your help and doing some digging, I'm getting deeper into the problem with my Audi A3 2003 TDI Sport. And I can tell you, it's been very fun learning! The problem with the car:

Car goes in to limp mode - Emission Control System light is on - code came up as P0234 (over boost) (another code also came up, see below) - car shudders when idle.

The two codes are:

16785/P0401/001025 - Exhaust Gas Recirculation (EGR) System: Insufficient Flow Detected

Possible Symptoms
Malfunction Indicator Light (MIL) ON
Reduced Exhaust Gas Recirculation (EGR)
Reduced Power Output/Engine running rough
Increased Emissions
Possible Causes
Exhaust Gas Recirculation (EGR) Flow restricted/clogged
Exhaust Gas Recirculation (EGR) Valve stuck closed/leaking/faulty
Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve faulty
Exhaust Gas Recirculation (EGR) System faulty
Possible Solutions
Check/Clean Exhaust Gas Recirculation (EGR) System
Check/Replace Exhaust Gas Recirculation (EGR) Valve
Check Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve
Special Notes
Some TDI-CR engines have a filter for the EGR that can become restricted and cause a "Insufficient Flow" code.

With the above, a) is it something to worry about, and if so what could it be and b) could sorting out that problem help sort the following code...

16618/P0234/000564 - Boost Pressure Regulation: Limit Exceeded (Over boost Condition)
Possible Symptoms
Malfunction Indicator Light (MIL) ON
Boost Pressure too high
Reduced Power Output
Possible Causes
Hoses incorrectly connected, disconnected, blocked or leaking
Boost Pressure Control Valve (N75) faulty
Boost Pressure Sensor (G31) faulty
Turbo Charger stuck/faulty
Possible Solutions
Check Charge Pressure Control System
Perform Output Test (to check the Turbo Charger)
Perform Basic Setting (to check the Charge Pressure Control)
Perform Pressure Test to locate Leaks
Check/Replace Boost Pressure Control Valve (N75)
Check/Replace Boost Pressure Sensor (G31)
Check/Replace Turbo Charger

Now, if they are 2 unrelated problems, with the over boost, I've done some research and come up with some solutions. It would be great to see what you guys think...

1. Could try the 'Mr Muscle' technique to see if this helps (Un-Sticking Your TDi VNT Turbo Vanes.....). Would, if this worked, the veins clog back up again and the problem happen again? If so, over what time frame?

2. I've found a really good post that gives a couple of options as to what it could be, and said that on quite a lot of occasions turbos are replaced unnecessarily. See here > Diagnosing and Fixing Limp mode for A4 1.9TDI - TDIClub Forums

But to summarise, it says it could be:

Bad Maf (Oxygen Sensor)
Leak in the vacuum system
Faulty N75
Bad actuator
Dirty gummed up turbo causing variable vanes to jam or stick

What do you guys think to the above?

3. In another article I read (A3 TDI 140, HELP Overboosting, Limp Mode!) the chap had his turbo reconed but it still didn't work. He was then told it could be a problem with the EGR (blocked?) or Mass Air Flow sensor. A potential problem with the cylinder headwas also mentioned... Thoughts?

So, to summarise, if anyone could rule out/elaborate on the above, it would a huge help. I am a novice, but learning all the time. So thank you! here are the key problems again...

Car goes in to limp mode - Emission Control System light is on - code came up as P0234 (over boost) - car shudders when idle.

Thank you!

PS I have no warranty, would it be worth getting one!?

 

[smurfworth]

Over boost - almost definately caused by clogged turbo
EGR system- EGR valve probably just needs a clean.

 

[stevowmt]

Thank you! Can a garage 'un clog' a turbo. I'm a novice haha... Thanks smurfworth

 

[smurfworth]

Well, I had some diesel cleaner sprayed through the maf on mine while it was running. Cured the over boost and limp mode for around a month, problem came back again and a recon turbo was fitted. Been fine ever since.

 

[stevowmt]

Hmm, thanks. how much was your reconded turbo? thanks

 

[hollows wife]

yes a garage can strip and clean the turbo properly the cleaning part takes a few hours ,that's why most dont want to do it as its faster to just swap turbo's .

 

[stevowmt]

Thanks Hollow. Any idea of cost? I suppose its money wasted if that doesn't actually fix the problem though. hmmm

 

[hollows wife]

price wise not too sure at a guess should be around £200 , it definately cures the overboost problem ,and it wont return within a month either , turbo gets removed, stripped completely ,vanes get stripped from turbo ,all carbon gets stripped from the internals completely and vanes get filed on edge to allow smoother movement for much longer . rest of turbo gets cleaned of contaminents .I f turbo gets removed to find excess play etc ,then owner should get notified and be able to decide to either carry on with clean and rebuild or replace turbo.

 

[stevowmt]

Great, thanks for your help Hollow, I'll give that a try!

 

[hollows wife]

where are you located ?

 

[stevowmt]

Car is in Cornwall. Do you think, looking at the 2 fault codes, that if I fixed the first, the turbo would be okay again? Or are they unrelated for sure? Steve

 

[hollows wife]

egr is probably clogged with crap like the turbo is . id be inclined to remove the egr and clean it . you cant make it any worse . but turbo is unrelated even if even is cleaned and fault clears overboost will still be a problem till turbo is stripped and cleaned.

 

[stevowmt]

nice thank you. would cleaning the egr perhaps sort the turbo problem? Just want to know before i spend £££ on the turbo!

 

[southylad]

Recon turbo and either delete or blank and map out egr job sorted

 

[stevowmt]

thanks southylad. is reconing the turbo the same as de clogging it?

 

[hollows wife]

nice thank you. would cleaning the egr perhaps sort the turbo problem? Just want to know before i spend £££ on the turbo!

no turbo would want cleaning as well , both jobs could be done on same day .

 

[hollows wife]

thanks southylad. is reconing the turbo the same as de clogging it?

recon turbo is basically a remanufactured turbo , you usually swap out a turbo for a recon one then send yours in and get the surcharge on the recon one back.

 

[southylad]

Reconditioned mate but at a reputable place

 

[stevowmt]

.

 

[stevowmt]

sorry about my previous post, mates at work thought it was a laugh!

So, my plans are...

A. Clean the EGR (can a garage do this or is it simple to follow some of the youtube videos I've seen)
B. See if that effects the turbo problem (I don't think it will) if not,
C. I may try the Mr Muscle approach, although I'm not sure about putting that through my engine :/
D. If I do that and it fails, I'll get the turbo stripped and cleaned.
£. If all that fails, looks like it's new turbo time. Recon or new? Thoughts?

Thanks all for your help, I'll keep you updated...

 

[stevowmt]

Hi All - quick update.

First of all, I tried Revive (Home) and it didn't work. Okay, it's cleaned out the engine, but I'm down £100...

Anyway, when doing the Revive, the mechanic noticed the a gauge/switch was set to full power (from what I can remember) on the turbo and had corroded there. On later inspection, a lot of the turbo was corroded. The labour to take the turbo out was £120.

So I'm £220 down but now know the problem. The solution? A new turbo...

The new turbo has been ordered and fitted tomorrow. The total cost for new turbo, Revive and labour plus an oil and filter change (which the mechanic advised) is £800.

Steve