A6 C5 2.5TDi No power and White Smoke

[dfh44]

Hi and help
Just bought above car and plugged in VAG com.
6 Pcodes present
P00523
P00532
P00550
P00575
P00667
P01376

All appear to point to wiring.
Also Noticed that coolant temp was low at 41 deg and gauge showing 90 deg.
All terminals on coolant sensor were corroded and full of water, Have swapped it and now seems to read senseable values. Power seems to have improved but still white smoke.
Appear to be lacking in boost, if you flor the throttle there is a big flat spot at 3250rpm

Will investigate further to any loose fitting turbo hoses and will check MAF sensor

Think the engine is ABF.

When sorted how do I get more power?
At a sensable cost.
Please help and thanks for looking

 

[Mudplugger]

Hi, and welcome to the forum.

If your car is in any way mechanically imperfect, as you say it is, I'd strongly advise that you start off by giving it a good service and get it back to where Audi intended before you start trying to modify it away from that position. Two main reasons: firstly you may find it's then quick enough anyway; and secondly, many power increases come from eroding some of the safety margins that Audi built in to protect the engine, and it sounds as though yours is already suffering in that department. If you already think you may have a loose turbo hose, then increasing the boost before fixing it isn't the best plan...

With your car safelt returned to good working order, a search of this forum (using the box towards the top right) will reveal a substantial number of previous discussions on the subject of chipping. That's the simple and cheap solution. If you want a lot more power from your 2.5Tdi then look at a mega-thread started by fjtwelve and read what he's done to his car. It's impressive, although far from cheap.

Personally though, as somebody who's currently commuting 200 miles daily, right now I'd prefer a chip that gives me an extra couple of MPG on the motorway...

 

[dfh44]

Thanks Mudplugger.
Intention was to get to good original runnig order, Wanted to know if I struggled towing my Caravan where and how to uprate the power.

Good advice well taken

Any Ideas what and where to start?

 

[fjtwelve]

ABF engine code not familiar, do you mean AFB ? In which case you have the 148bhp 229ftlb version. See here for more info List of discontinued Volkswagen Group diesel engines - Wikipedia, the free encyclopedia.

As far as white smoke is concerned, try this thread http://www.audi-sport.net/vb/diesel-forum/19757-00-2-5tdi-clouds-white-smoke.html

Essential engine and brakes are back to standard before you do anything to tune up. You have to make sure all those servicing items and replacements that should have been done at the last "services" that turned out to be oil changes are now done. I have spent a lot of money replacing bits that have turned out to be worn out or defective, once they were fixed the tuning suddenly started to work. The actual tuning work is only about half of what i have spent.

Tuning begins with a tuning box, simple to fit, immediate change, this forum has opinions on a number of them. Tunit will give you 180bhp/267ftlb for instance. You can take your box from car to car. Secondhand ones are regularly on ebay. The more expensive ones are at the bottom of the generic remap price range, which will give you more power and torque again, and improved spread and smoothness. Celtic will take you to 190bhp/270ftlb for instance. Choose the word of mouth/forum recommended best local tuner, if theres a problem you don't want a long drive/tow to get it fixed. Next you can start replacing bolt on parts like nozzles and turbos with a customised remap which is where i am. Finally you start taking the engine to bits and modifying the internals, not seen much in the UK for the 2.5 but the Finns in particular seem to like this and get big improvements.

As far as economy is concerned, in theory having the increased torque and power means you stay in a higher gear at lower speed and thereby increase economy, and mapping will refine the universal setting that Audi use to be more efficient. Mine feels like its standing still at 70 on a whiff of throttle. If i can persuade myself to do this the economy makes a bolt for the high 30s. The fact that i am getting maybe 29 might indicate that once you have that extra power and torque its difficult not to use it. My last complaint was that its not pulling past 120 as quick as it did on the first pass at the remap.....

Publish what you do, people are always interested and in this case, there is little info around on tuning this engine

 

[Mudplugger]

fjtwelve has just told you more about tuning your specific engine than I ever could, so I'll say no more on that subject.

I will however say that the A6 Allroad 2.5 Tdi has won the Camping & Caravan Club's towcar of the year award (in it's class, which is just below the big 4x4s) on more that one occasion, as subsequently has the 3.0 Tdi, suggesting that it should be capable enough unless you have a truly huge caravan. I think the only reason it didn't win this year was on price grounds or similar, but the A4 Allroad 2.0 Tdi won the next class down I think. If I stumble over the magazine, I'll come back and edit this comment with accurate fact rather than memory!

My point however (as in previous posts, so sorry to repeat) is that you should definitely get your car back to top standard spec, as Audi intended it to be, and then see how well it copes before you worry about trying to "improve" it. If your car's 10 years old, and suffering a huge list of faults (as you suggest), then your single biggest "improvement" is likely to be restoring it to factory standard condition!

If you do end up making modifications beyond that, and they work well, then I for one will be very interested to learn about them in this forum because heavy towing is one of the reasons that I bought my Allroad...

 

[dfh44]

Hi Guys
Many thanks for repiles.

Further investigation has show that extra fuel being added as boost pressure not reached, it does this to keep the required torque demand of the speed of the engine.
EGR Valve has been removed and sonic cleaned, All intake system has had the same treatment, so all as new.

But did find minimiul movement on the wastegate acuator, disconnected the link rod and accuator does move free and responds to throttle demand, but the waste gate lever was stuck, very stuck, It has been removed and sent away for service and refurb great place CR Turbos, have a look at their site, would be worth keeping address.
Just waiting for it to be returned and will update after refitting.

 

[dfh44]

FYI Guys
White smoke emmitted from the exhaust is more common to being unburnt Fuel,But could be confussed with water leaking into the combustion chamber and exits as steam, usual tell tale sign could be bubbles and excessive pressure in the header tank
Black smoke is excessively overrich fuelling and burnt, hence the soot,BURNT PRODUCT.
Hope this will clear up some questions regarding the type os smoke emmitted via the exhaust.

 

[adamss24]

If its an AFB then the crankcase breather might be plugged and overpressurising the engine- hence the smoke. Do a search on that as there are a few how to on the net...